MANUFACTURING METALLIC ARTICLES USING ROTATIONAL TOOLS

FIELD OF THE INVENTION

One or more implementations relate to the formation of articles from a material disposed in a die using a rotational tool.

BACKGROUND

Manufactured articles can be formed using a number of processes. In some cases, articles can be produced using dies and molds. In these situations, a material is heated and/or pressed to conform to the shape of a die or mold. Additive manufacturing and subtractive manufacturing can also be used to manufacture articles according to a given shape or design. Machining processes can also be implemented to manufacture articles. For example, roughing and finishing operations can be performed in the manufacturing process for a number of articles. Existing techniques for manufacturing articles can be limited in the types of articles that can be produced that have particular shapes and that also possess physical properties that are suitable for an intended application. Many article manufacturing processes can also specify that multiple steps are to be performed and can be inefficient with respect to use of resources and/or machinery.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a process to manufacture an article using a die and a rotational tool, in accordance with one or more example implementations.

FIG. 2 illustrates a framework to manufacture an article using a die and a threaded tool, in accordance with one or more example implementations.

FIG. 3 illustrates a framework to produce an article using a die and a tool without threads, in accordance with one or more example implementations.

FIG. 4 illustrates a first rotational tool having a section that is fully threaded and a second rotational tool having a section that is partially threaded, in accordance with one or more example implementations.

FIG. 5 illustrates a third rotational tool including a section in which no threads are present and illustrates an example die, in accordance with one or more example implementations.

FIG. 6 includes a schematic of a step-by-step friction stir forging process and images of example starting materials and formed articles.

FIG. 7 includes an optical micrograph of a 14-tooth AZ31 magnesium gear and a magnified view of two teeth of the gear indicating the radial flow of material during the manufacturing process for the gear.

FIG. 8 includes smoothed particle hydrodynamics (SPH) simulations showing strain rate and temperature for a 14-tooth gear produced in accordance with one or more implementations described herein.

FIG. 9 includes electron backscatter diffraction (EBSD) images for an A231 magnesium gear including images showing grain size distributions near the tooth edge manufactured in accordance with one or more examples described herein.

FIG. 10 includes (0001) pole figures of a tip of a tooth, a mid-section of the tooth, and a base section of the tooth.

FIG. 11 includes EBSD maps taken in the longitudinal through-thickness direction of the tools, inverse pole figure (IPF) maps, and high angle grain boundary (HAGB) and low angle grain boundary (LAGB) maps for an AZ31 magnesium gear tooth.

FIG. 12 includes images related to SPH modeling of temperature and strain rate distribution of a gear tooth made in accordance with one or more implementations described herein.

FIG. 13 includes images corresponding to SPH simulations of an AA 7075-T6 gear showing strain rate distribution and temperature distributions for the whole gear as well as magnified versions of the simulations for two teeth of the gear.

FIG. 14 includes EBSD maps including IPF maps, and HAGB and low angle grain boundary LAGB maps for an AA7075-T6 gear.

FIG. 15 includes EBSD maps in the longitudinal through-thickness direction of the core region including IPF maps, and HAGB and low angle grain boundary LAGB maps for an AA7075-T6 gear.

FIG. 16 is a schematic diagram of the core of a gear used for SPH models including particle distribution, temperature, and strain rate distribution.

FIG. 17 includes a schematic for steps of manufacturing gears from powder then friction consolidation followed by friction stir forging as well as scanning electron microscopy (SEM) images of different portions of an AA5083 and 10% by volume titanium diboride composite gear.

DETAILED DESCRIPTION

The following description includes a preferred best mode of implementations of the present disclosure. It will be clear from this description of the disclosure that the disclosure is not limited to these illustrated implementations but that the disclosure also includes a variety of modifications and embodiments thereto. Therefore, the present description should be seen as illustrative and not limiting. While the disclosure is susceptible of various modifications and alternative constructions, it should be understood, that there is no intention to limit the disclosure to the specific form disclosed, but, on the contrary, the disclosure is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the disclosure.

In various examples, industrial processes can be used to manufacture metallic articles. In at least some examples, the metallic articles can be used in transportation vehicles, motors, generators, transformers, and other machines. For example, industrial processes can be used to produce gears, rotors, stators, magnetic articles, and the like that are components of vehicles or machine. Typically, the metallic materials can be relatively heavy and can reduce the performance of the vehicle or machine in which the articles formed from the metallic materials are located. In many situations, replacing articles in the vehicles and machines having the relatively heavy articles with articles having a lighter weight can improve the efficiency of the vehicles and machines. However, in various situations, articles formed from lighter weight materials may not possess mechanical properties that are suitable for the intended use of the articles.

In at least some examples, manufacturing processes implemented to produce articles from relatively light weight materials can include forming processes. The forming processes can include at least one of casting, sintering, injection molding, extruding, cold drawing, stamping, preforming, or forging. Additionally, processes used to manufacture articles from relatively lightweight materials can include one or more machining processes. The one or more machining process can include at least one of one or more roughing processes or one or more finishing processes. The one or more roughing processes can include form milling, rack generation, gear shaping and/or hobbing. The one or more finishing processes can include shaving, grinding, burnishing, lapping, and/or honing. Often, manufacturing articles from relatively lightweight materials can include performing several of these processes using different pieces of machinery, which can be a time-consuming procedure.

The implementations herein can manufacture axis symmetrical shapes such as gears, rotors, stators, magnets, and so forth from relatively lightweight materials. In one or more examples, the implementations described herein can be used to produce articles from aluminum and alloys of magnesium, metal matrix composite alloys and soft and hard magnets. The articles produced according to implementations herein can have physical properties that are improved with respect to existing lightweight components that have been produced to replace heavier versions of the components.

In various examples, existing melt based additive techniques to produce relatively lightweight articles for use in vehicles or machinery can rely on at least one of diffusion processes or particle sizes of the materials used to form the articles. The implementations described herein provide greater flexibility in the materials that can be used to manufacture articles for use in vehicles or machinery because the implementations do not rely on diffusion characteristics or particle size of metallic materials to achieve suitable mechanical properties of the articles being produced. Instead, the implementations herein utilize a tool that contacts metallic material disposed in a die. The tool and protocols for using the tool are configured to cause compaction of the metallic material in the die as well as cause shearing of the metallic material disposed in the die. In this way, boundaries of the metallic particles can break down and bond to provide improved physical properties of the finally formed articles. Additionally, the protocols implemented to form the articles can cause temperatures of the metallic material to increase. In at least some examples, the protocols implemented to form the articles can cause temperatures to remain below a melting point of the metallic material. Further, the implementations described herein can be performed with fewer steps and fewer pieces of machinery than existing processes. That is, rather than moving an article from station to station and performing a number of different processes to form articles from relatively lightweight materials, the implementations described herein can form an article within a die using a single tool.

FIG. 1 illustrates a process 100 to manufacture an article using a die and a rotational tool, in accordance with one or more example implementations. The process 100 can include, at 102, providing material for forming an article. In one or more examples, the material can include a preformed object 104. The preformed object 104 can have a given shape. For example, the preformed object 104 can have the shape of a cylinder, a block, and the like. The material can also include a powder 106. The preformed object 104 and the powder 106 can be comprised of one or more metallic materials. To illustrate, the preformed object 104 can be comprised of at least one of aluminum, silicon, iron, copper, manganese, magnesium, chromium, calcium, iron, zinc, or titanium. In addition, the preformed object 104 and the powder 106 can be comprised of one or more ceramic materials. In various examples, the preformed object 104 and the powder 106 can be comprised of a mixture of one or more metallic materials and one or more ceramic materials. The materials comprising the preformed object 104 and the powder 106 can have physical properties and mechanical properties that are suitable for the intended purpose of the article being formed from the preformed object 104 or the powder 106.

At 104, the process 100 can include disposing the material to be used on forming the article into a die 110. For example, the preformed object 104 or the powder 106 can be placed into the die 110 using one or more manual techniques and/or one or more mechanical techniques. In one or more illustrative examples, the preformed object 104 or the powder 106 can be placed in the die 110 using one or more automated processes. In various examples, the preformed object 104 or the powder 106 can be placed in the die 110 using one or more robotic devices.

The die 110 can be formed from one or more metallic materials. For example, the die 110 can be formed from at least one of carbon steel, tool steel, stainless steel, galvanized steel, or nickel-chromium alloys. The die 110 can be formed in a pattern 112 that correspond to a shape of the article to be formed using the die 110. In scenarios where the preformed object 104 is used to produce an article, the preformed object 104 can have dimensions that correspond to the dimensions of the die 110. To illustrate, the preformed object 104 can have a diameter or a width that corresponds to an inner diameter or inner width of the die 110. Additionally, a height of the preformed object 104 can correspond to a height of the die 110. In one or more illustrative examples, the die 110 can be used to produce axis symmetrical shapes. In various examples, the die 110 can be used to produce gears, rotors, stators, magnets, vehicle motor components, and so forth.

In addition, the process 100 can include, at 114, contacting the material 118 disposed in the die 110 with a rotational tool 116. In one or more examples, the rotational tool 116 can include a threaded end that contacts the material 118. In one or more additional examples, the rotational tool 116 can include a partially threaded end that contacts the material 118. In one or more further examples, the end of the rotational tool 116 that contacts the material 118 can be free from threads. The rotational tool 116 can be comprised of one or more metallic materials. To illustrate, the rotational tool 116 can be comprised of at least one of carbon steel, tool steel, stainless steel, galvanized steel, nickel-chromium alloys, aluminum, or aluminum alloys.

The rotational tool 116 can contact the material 118 according to a protocol. The protocol can specify a vertical speed of the rotational tool 116 and a rotational speed of the rotational tool 116. The protocol can also specify a rotational direction of the rotational tool 116. The protocol implemented with respect to the rotational tool 116 can indicate changes to at least one of vertical speeds or rotational speeds of the rotational tool 116 at different depths of the die. For example, the protocol implemented with respect to the rotational tool can indicate a first vertical speed and a first rotational speed when the rotational tool 116 is located at a first range of depths of the die. As the rotational tool 116 moves through the die 110, the protocol can indicate that in response to the rotational tool 116 being located at a threshold depth, the vertical speed of the rotational tool 116 is modified to a second vertical speed and the rotational speed of the rotational tool 116 is modified to a second rotational speed. In various examples, the protocol implemented with respect to the rotational tool 116 can be based on a composition of the material 118 disposed in the die 110. In addition, the protocol implemented with respect to the rotational tool 116 can be based on the pattern 112 of the die 110.

Further, at 120, the process 100 can include producing a formed article 122. After the protocol of the rotational tool 116 has been implemented, the formed article 118 can be removed from the die 110. In one or more examples, the formed article 122 can remain in the die 110 for a period of time before being removed from the die 110. In various examples, the formed article 122 can remain in the die 110 as part of a cooling operation before being removed from the die 122. In addition, although the illustrative example of FIG. 1 shows a formed article 122 with a circular or elliptical shape, in other implementations, the formed article 122 can have different shapes. In various examples, the formed article 122 can have a shape including a number of protrusions.

The formed article 122 can have dimensions, such as a diameter, width, and/or height, from about 1 millimeter (mm) to about 15 centimeter (cm), from about 5 mm to about 10 cm, from about 10 mm to about 5 cm, from about 5 mm to about 25 mm, from about 10 mm to about 10 cm, from 1 cm to about 8 cm, from about 0.5 cm to about 5 cm, from about 5 cm to about 10 cm, from about 2 cm to about 4, from about 4 cm to about 6 cm, from about 6 cm to about 8 cm, or from about 1 cm to about 4 cm.

FIG. 2 illustrates a framework 200 to manufacture an article using a die and a threaded tool, in accordance with one or more example implementations. The framework 200 can include, at 202, placing a preformed object 204 into a die 206. In one or more examples, the preformed object 204 can include at least one of one or more metallic materials or one or more ceramic materials. In at least some examples, the preformed object 204 can be comprised of aluminum. In various examples, the preformed object 204 can be comprised of an alloy of aluminum. For example, the preformed object 204 can be comprised of aluminum and at least one of silicon, iron, copper, manganese, magnesium, chromium, zinc, or titanium. In still other examples, the preformed object 204 can be comprised of an alloy of magnesium. To illustrate, the preformed object 204 can be comprised of magnesium and at least one of aluminum, zinc, manganese, silicon, copper, calcium, iron, or nickel. In one or more illustrative examples, the preformed object 204 can comprise a billet.

In situations where the preformed object 204 includes a mixture of one or more metallic materials and one or more ceramic materials, the preformed object 204 can be produced by consolidating a mixture of a first powder including the one or more metallic materials and a second powder including the one or more ceramic materials. For example, the first powder and the second powder can undergo a friction consolidation to produce the preformed object 204. In one or more illustrative examples, the one or more metallic materials can include an alloy of aluminum including at least one of silicon, iron, copper, manganese, magnesium, chromium, zinc, or titanium and the one or more ceramic materials can include titanium diboride (TiB₂).

In one or more examples, the preformed object 204 can be comprised of at least about 50% by weight aluminum, at least about 52% by weight aluminum, at least about 54% by weight aluminum, at least about 56% by weight aluminum, at least about 58% by weight aluminum, at least about 60% by weight aluminum, at least about 62% by weight aluminum, at least about 64% by weight aluminum, at least about 66% by weight aluminum, at least about 68% by weight aluminum, at least about 70% by weight aluminum, at least about 72% by weight aluminum, or at least about 74% by weight aluminum. Additionally, the preformed object 204 can be comprised of no greater than about 99% by weight aluminum, no greater than about 97% by weight aluminum, no greater than about 95% by weight aluminum, no greater than about 93% by weight aluminum, no greater than about 91% by weight aluminum, no greater than about 89% by weight aluminum, no greater than about 87% by weight aluminum, no greater than about 85% by weight aluminum, no greater than about 83% by weight aluminum, no greater than about 81% by weight aluminum, or no greater than about 79% by weight aluminum. Further, the preformed object 204 can be comprised of from about 50% by weight to about 99% by weight aluminum, from about 55% by weight to about 90% by weight aluminum, from about 60% by weight aluminum to about 85% by weight aluminum, from about 70% by weight aluminum to about 90% by weight aluminum, from about 75% by weight aluminum to about 95% by weight aluminum, from about 70% by weight aluminum to about 80% by weight aluminum, from about 75% by weight to about 85% by weight aluminum, from about 80% by weight to about 90% by weight aluminum, or from about 85% by weight to about 95% aluminum. In still other examples, the preformed object 204 can be at least partly comprised of an aluminum 7000 series alloy. In one or more illustrative examples, the preformed object 204 can be comprised of an AA 7075 alloy. For example, the preformed object 204 can be comprised of an AA 7075-T6 alloy.

In one or more additional illustrative examples, when the preformed object 204 is comprised of a mixture of one or more aluminum materials and one or more ceramic materials, the one or more aluminum materials included in the preformed object 204 can include an AA5083 alloy. In these scenarios, the preformed object 204 can be comprised of at least about 3% by weight TiB₂, at least about 5% by weight TiB₂, at least about 8% by weight TiB₂, at least about 10% by weight TiB₂, at least about 12% by weight TiB₂, at least about 15% by weight TiB₂, at least about 18% by weight TiB₂, or at least about 20% by weight TiB₂. In one or more further illustrative examples, the preformed object 204 can be comprised of no greater than about 40% by weight TiB₂, no greater than about 38% by weight TiB₂, no greater than about 35% by weight TiB₂, no greater than about 32% by weight TiB₂, no greater than about 30% by weight TiB₂, no greater than about 28% by weight TiB₂, or no greater than about 25% by weight TiB₂. In various examples, the preformed object 204 can include from about 3% by weight to about 40% by weight TiB₂, from about 8% by weight to about 30% by weight TiB₂, from about 12% by weight to about 25% by weight TiB₂, from about 10% by weight to about 20% by weight TiB₂, from about 20% by weight to about 30% by weight TiB₂, from about 10% by weight to about 15% by weight TiB₂, from about 15% by weight to about 20% by weight TiB₂, from about 20% by weight to about 25% by weight TiB₂, or from about 25% by weight to about 30% by weight TiB₂.

In one or more additional examples, the preformed object 204 can be comprised of at least about 50% by weight magnesium, at least about 52% by weight magnesium, at least about 54% by weight magnesium, at least about 56% by weight magnesium, at least about 58% by weight magnesium, at least about 60% by weight magnesium, at least about 62% by weight magnesium, at least about 64% by weight magnesium, at least about 66% by weight magnesium, at least about 68% by weight magnesium, at least about 70% by weight magnesium, at least about 72% by weight magnesium, or at least about 74% by weight magnesium. Additionally, the preformed object 204 can be comprised of no greater than about 99% by weight magnesium, no greater than about 97% by weight magnesium, no greater than about 95% by weight magnesium, no greater than about 93% by weight magnesium, no greater than about 91% by weight magnesium, no greater than about 89% by weight magnesium, no greater than about 87% by weight magnesium, no greater than about 85% by weight magnesium, no greater than about 83% by weight magnesium, no greater than about 81% by weight magnesium, or no greater than about 79% by weight magnesium. Further, the preformed object 204 can be comprised of from about 50% by weight to about 99% by weight magnesium, from about 55% by weight to about 90% by weight magnesium, from about 60% by weight magnesium to about 85% by weight magnesium, from about 70% by weight magnesium to about 90% by weight magnesium, from about 75% by weight magnesium to about 95% by weight magnesium, from about 70% by weight magnesium to about 80% by weight magnesium, from about 75% by weight to about 85% by weight magnesium, from about 80% by weight to about 90% by weight magnesium, or from about 85% by weight to about 95% magnesium. In still other examples, the preformed object 204 can be at least partly comprised of an aluminum 7000 series alloy. In one or more illustrative examples, the preformed object 204 can be comprised of an AZ31 alloy. To illustrate, the preformed object 204 can be comprised of an AZ31B alloy.

In one or more further examples, the preformed object 204 can have a melting temperature of at least about 550° C., at least about 555° C., at least about 560° C., at least about 565° C., at least about 570° C., at least about 575° C., at least about 580° C., at least about 585° C., at least about 590° C., at least about 595° C., at least about 600° C., at least about 605° C., at least about 610° C., at least about 615° C., or at least about 620° C. Additionally, the preformed object 204 can have a melting temperature no greater than about 800° C., no greater than about 790° C., no greater than about 780° C., no greater than about 770° C., no greater than about 760° C., no greater than about 750° C., no greater than about 740° C., no greater than about 730° C., no greater than about 720° C., no greater than about 710° C., no greater than about 700° C., no greater than about 690° C., no greater than about 680° C., no greater than about 670° C., no greater than about 660° C., or no greater than about 650° C. In one or more illustrative examples, the preformed object 204 can have a melting temperature from about 550° C. to about 800° C., from about 580° C. to about 750° C., from about 600° C. to about 700° C., from about 580° C. to about 680° C., from about 580° C. to about 660° C., from about 590° C. to about 670° C., from about 600° C. to about 680° C., from about 610° C. to about 690° C., from about 620° C. to about 700° C., from about 580° C. to about 640° C., from about 590° C. to about 650° C., from about 600° C. to about 660° C., from about 610° C. to about 670° C., from about 620° C. to about 680° C., from about 630° C. to about 690° C., from about 640° C. to about 700° C., from about 600° C. to about 640° C., from about 610° C. to about 650° C., from about 620° C. to about 660° C., from about 630° C. to about 670° C., from about 640° C. to about 680° C., from about 650° C. to about 690° C., or from about 660° C. to about 700° C.

The preformed object 204 can have a height 208 and a width 210. In situations where the preformed object 204 has the shape of a cylinder, the width 210 can correspond to a diameter. In one or more examples, the height 208 can be from 10 millimeters (mm) to about 60 mm, from about 10 mm to about 50 mm, from about 10 mm to about 40 mm, from about 10 mm to about 30 mm, from about 10 mm to about 20 mm, from about 20 mm to about 60 mm, from about 20 mm to about 50 mm, from about 20 mm to about 40 mm, from about 20 mm to about 30 mm, from about 30 mm to about 60 mm, from about 30 mm to about 50 mm, from about 30 mm to about 40 mm, from about 40 mm to about 60 mm, from about 40 mm to about 50 mm, or from about 50 mm to about 60 mm. Additionally, the width 210 can be from about 10 mm to about 80 mm, from about 10 mm to about 70 mm, from about 10 mm to about 60 mm, from about 10 mm to about 50 mm, from about 10 mm to about 40 mm, from about 10 mm to about 30 mm, from about 10 mm to about 20 mm, from about 20 mm to about 80 mm, from about 20 mm to about 70 mm, from about 20 mm to about 60 mm, from about 20 mm to about 50 mm, from about 20 mm to about 40 mm, from about 20 mm to about 30 mm, from about 30 mm to about 80 mm, from about 30 mm to about 70 mm, from about 30 mm to about 60 mm, from about 30 mm to about 50 mm, from about 30 mm to about 40 mm, from about 40 mm to about 80 mm, from about 40 mm to about 70 mm, from about 40 mm to about 60 mm, from about 40 mm to about 50 mm, from about 50 mm to about 80 mm, from about 50 mm to about 70 mm, from about 50 mm to about 60 mm, from about 60 mm to about 80 mm, from about 60 mm to about 70 mm, or from about 70 mm to about 80 mm.

The die 206 can have a pattern 212. The pattern 212 can correspond to an axis symmetrical shape. In one or more examples, the pattern 212 can have a center region 214 with a number of projections 216 extending from the center region 2142. In various examples, the center region 214 of the pattern can comprise a circular shape, an elliptical shape, or a rectangular shape. In one or more additional examples, the projections 216 extending from the center region 214 can include teeth. For example, the projections 216 can include teeth of a gear. In one or more further examples, the projections 216 can include fins. In still other examples, 2 projections 216 can extend from the center region 214 of the pattern 212, 3 projections 216 can extend from the center region 214 of the pattern 212, 4 projections 216 can extend from the center region 214 of the pattern 212, 5 projections 216 can extend from the center region 214 of the pattern 212, 6 projections 216 can extend from the center region 214 of the pattern 212, 7 projections 216 can extend from the center region 214 of the pattern 212, 8 projections 216 can extend from the center region 214 of the pattern 212, 9 projections 216 can extend from the center region 214 of the pattern 212, 10 projections 216 can extend from the center region 214 of the pattern 212, 11 216 projections can extend from the center region 214 of the pattern 212, 12 projections 216 can extend from the center region 214 of the pattern 212, 13 projections 216 can extend from the center region 214 of the pattern 212, 14 projections 216 can extend from the center region 214 of the pattern 212, 15 projections 216 can extend from the center region 214 of the pattern 212, 16 projections 216 can extend from the center region 214 of the pattern 212, 17 projections 216 can extend from the center region 214 of the pattern 212, 18 projections 216 can extend from the center region 214 of the pattern 212, 19 projections 216 can extend from the center region 214 of the pattern 212, or 20 projections 216 can extend from the center region 214 of the pattern 212. In at least some examples, the number of projections 216 extending from a center region 214 of the pattern 212 can be greater than 20. Additionally, although the illustrative example of FIG. 2 shows that the preformed object 204 includes projections 216 extending from a center region 214 of the pattern 212, in one or more additional examples, projections can be absent from the preformed object 204.

The projections 216 extending from the center region 214 can be spaced according to a pitch. In various examples, the pitch between the projections 216 can be the same or substantially the same. In still other examples, the pitch between at least a portion of the projections 216 can be different. In one or more examples, the pitch between the projections 216 can be from about 0.3 mm to about 20 mm, from about 0.5 mm to about 15 mm, from about 0.8 mm to about 10 mm, from about 1 mm to about 5 mm, from about 0.3 mm to about 2 mm, from about 0.5 mm to about 1.5 mm, from about 0.5 mm to about 1.2 mm, from about 0.5 mm to about 1 mm, from about 0.8 mm to about 2 mm, from about 0.8 mm to about 1.6 mm, from about 0.8 mm to about 1.2 mm, from about 1 mm to about 2 mm, or from about 1 mm to about 1.5 mm.

The width of the pattern 212 can correspond to a width 210 of the preformed object 204 such that the preformed object 204 fits within the center region 214. In one or more examples, the preformed object 204 can fit within the center region 214 such that at least a portion of the outer walls of the preformed object 204 contact at least a portion of the center region 214. In still other examples, the preformed object 204 can fit within the center region 214 such that the preformed object 204 can be removed via gravity or a magnet. In one or more illustrative examples, the width of the center region 214 can have a width that is from about 1 times the width 210 to about 1.3 times the width 210, from about 1 times the width 210 to about 1.2 times the width 210, from about 1 times the width 210 to about 1.1 times the width 210, from about 1 times the width 210 to about 1.08 times the width 210, from about 1 times the width 210 to about 1.06 times the width 210, from about 1 times the width 210 to about 1.04 times the width 210, or from about 1 times the width 210 to about 1.02 times the width 210.

The die 206 can be formed from at least one of at least one of carbon steel, tool steel, stainless steel, galvanized steel, or nickel-chromium alloys. In one or more examples, the die 206 can have an open end in which the preformed object 204 is inserted and a bottom end that is at least partially closed. In one or more additional examples, the die 206 can have an open end in which the preformed object 204 is inserted and a bottom end that is also open.

The framework 200 can also include, at 218, inserting a tool 220 into the preformed object 204 disposed in the die 206. The tool 220 can include a first shoulder section 222 having a first diameter and a second shoulder section 224 having a second diameter that is smaller than the first diameter. The tool 220 can also include an extended member 226. The extended member 226 can include a number of threads. In various examples, the extended member 226 can include one or more threaded regions and one or more regions without threads. The tool 220 can be formed from at least one of carbon steel, tool steel, stainless steel, galvanized steel, nickel-chromium alloys. In one or more illustrative examples, the tool 220 can be comprised of H13 tool steel. The tool 220 can be moved in a vertical direction to contact the preformed object 204 disposed in the die 206. For example, the tool 220 can move downward to contact the preformed object 204 disposed in the die 206. Additionally, the tool 220 can move in a rotational direction. In one or more examples, the tool 220 can be rotated in a clockwise direction. In one or more additional examples, the tool 220 can be rotated in a counterclockwise direction.

At 228, the framework 200 can include performing a protocol using the tool 220 to produce a formed article 230. In one or more examples, the protocol can be implemented by a computing device that controls operation of the tool 220. In various examples, the computing device can execute software that causes the protocol to be implemented by one or more pieces of machinery. In at least some examples, the tool 220 can be part of a piece of machinery that can be used to position the die 206 and the tool 220 such that the extended member 226 of the tool 220 can be inserted into the preformed object 204 disposed in the die 206. The machinery can also cause at least one of the tool 220 or the die 206 to move in a vertical direction.

The protocol can indicate a vertical speed of the tool 220 and a rotational speed of the tool 220. The protocol can also indicate the vertical speed and the rotational speed of the tool 220 at one or more depths that the extended member 226 is inserted into the die 206. The protocol can indicate that the tool 220 is to have one or more first vertical speeds and one or more first rotational speeds until a first depth 232 and one or more second vertical speeds and one or more second rotational speeds until a second depth 234. In addition, the protocol can indicate that the tool 220 is to have one or more third vertical speeds and one or more third rotational speeds until the third depth 236 and one or more fourth vertical speeds and one or more fourth rotational speeds until the fourth depth 238. In at least some examples, the fourth depth 238 can correspond to a bottom end of the die 206.

In one or more illustrative examples, the one or more first vertical speeds can be from about 10 millimeters per minute (mmPM) to about 100 mmPM, from about 20 mmPM to about 80 mmPM, from about 30 mmPM to about 60 mmPM, from about 10 mmPM to about 30 mmPM, from about 20 mmPM to about 40 mmPM, from about 30 mmPM to about 50 mmPM, from about 10 mmPM to about 20 mmPM, from about 20 mmPM to about 30 mmPM, or from about 30 mmPM to about 40 mmPM. The one or more first rotational speeds can be from about 80 rotations per minute (RPM) to about 500 RPM, from about 100 RPM to about 450 RPM, from about 150 RPM to about 400 RPM, from about 200 RPM to about 350 RPM, from about 100 RPM to about 200 RPM, from about 200 RPM to about 300 RPM, from about 300 RPM to about 400 RPM, from about 100 RPM to about 150 RPM, from about 150 RPM to about 200 RPM, from about 200 RPM to about 250 RPM, from about 250 RPM to about 300 RPM, or from about 300 RPM to about 350 RPM. Measured from a top of the preformed object 204, the first depth 232 can be from about 3% of the height 208 of the preformed object 204 within the die 206 to about 15% of the height 208, from about 4% of the height 208 to about 12% of the height 208, from about 5% of the height 208 to about 10% of the height 208, from about 3% of the height 208 to about 7% of the height 208, from about 4% of the height 208 to about 8% of the height 208, from about 5% of the height 208 to about 9% of the height 208, from about 4% of the height 208 to about 7% of the height 208, from about 5% of the height 208 to about 8% of the height 208, from about 6% of the height to about 9% of the height 208, from about 4% of the height 208 to about 6% of the height 208, from about 5% of the height 208 to about 7% of the height 208, or from about 6% of the height 208 to about 8% of the height 208.

In one or more additional illustrative examples, the one or more second vertical speeds can be from about 2 mmPM to about 40 mmPM, from about 5 mmPM to about 30 mmPM, from about 8 mmPM to about 25 mmPM, from about 10 mmPM to about 30 mmPM, from about 10 mmPM to about 20 mmPM, from about 15 mmPM to about 25 mmPM, from about 20 mmPM to about 30 mmPM, or from about 30 mmPM to about 40 mmPM. The one or more second rotational speeds can be from about 800 RPM to about 1600 RPM, from about 1000 RPM to about 1500 RPM, from about 1200 RPM to about 1400 RPM, from about 800 RPM to about 1000 RPM, from about 1000 RPM to about 1200 RPM, from about 1200 RPM to about 1400 RPM, from about 1400 RPM to about 1600 RPM, from about 1000 RPM to about 1100 RPM, from about 1100 RPM to about 1200 RPM, from about 1200 RPM to about 1300 RPM, from about 1300 RPM to about 1400 RPM, from about 1400 RPM to about 1500 RPM, or from about 1500 RPM to about 1600 RPM. Measured from a top of the preformed object 204, the second depth 234 can be from about 15% of the height 208 of the preformed object 204 within the die 206 to about 40% of the height 208, from about 18% of the height 208 to about 35% of the height 208, from about 20% of the height 208 to about 32% of the height 208, from about 15% of the height 208 to about 18% of the height 208, from about 16% of the height 208 to about 19% of the height 208, from about 17% of the height 208 to about 20% of the height 208, from about 18% of the height 208 to about 21% of the height 208, from about 19% of the height 208 to about 22% of the height 208, from about 20% of the height to about 23% of the height 208, from about 21% of the height 208 to about 24% of the height 208, from about 22% of the height 208 to about 25% of the height 208, from about 23% of the height 208 to about 26% of the height 208, from about 24% of the height 208 to about 27% of the height 208, from about 25% of the height 208 to about 28% of the height 208, from about 26% of the height 208 to about 29% of the height 208, or from about 27% of the height 208 to about 30% of the height 208.

In one or more further illustrative examples, the one or more third vertical speeds can be from about 2 mmPM to about 40 mmPM, from about 5 mmPM to about 30 mmPM, from about 8 mmPM to about 25 mmPM, from about 10 mmPM to about 30 mmPM, from about 10 mmPM to about 20 mmPM, from about 15 mmPM to about 25 mmPM, from about 20 mmPM to about 30 mmPM, or from about 30 mmPM to about 40 mmPM. The one or more third rotational speeds can be from about 1000 RPM to about 2200 RPM, from about 1200 RPM to about 2000 RPM, from about 1400 RPM to about 1800 RPM, from about 1200 RPM to about 1500 RPM, from about 1300 RPM to about 1600 RPM, from about 1400 RPM to about 1700 RPM, from about 1500 RPM to about 1800 RPM, from about 1600 RPM to about 1900 RPM, from about 1700 RPM to about 2000 RPM, from about 1800 RPM to about 2100 RPM, from about 1300 RPM to about 1500 RPM, from about 1400 RPM to about 1600 RPM, from about 1500 RPM to about 1700 RPM, from about 1600 RPM to about 1800 RPM, from about 1700 RPM to about 1900 RPM, from about 1800 RPM to about 2000 RPM, or from about 1900 RPM to about 2100 RPM. Measured from a top of the preformed object 204, the third depth 236 can be from about 50% of the height 208 of the preformed object 204 within the die 206 to about 85% of the height 208, from about 60% of the height 208 to about 80% of the height 208, from about 60% of the height 208 to about 75% of the height 208, from about 55% of the height 208 to about 70% of the height 208, from about 60% of the height 208 to about 75% of the height 208, from about 65% of the height 208 to about 80% of the height 208, from about 60% of the height 208 to about 64% of the height 208, from about 64% of the height 208 to about 68% of the height 208, from about 68% of the height to about 72% of the height 208, from about 72% of the height 208 to about 76% of the height 208, from about 76% of the height 208 to about 80% of the height 208, or from about 80% of the height 208 to about 84% of the height 208.

In still additional illustrative examples, the one or more fourth vertical speeds can be from about 40 mmPM to about 150 mmPM, from about 60 mmPM to about 120 mmPM, from about 75 mmPM to about 115 mmPM, from about 50 mmPM to about 60 mmPM, from about 60 mmPM to about 70 mmPM, from about 70 mmPM to about 80 mmPM, from about 80 mmPM to about 90 mmPM, from about 90 mmPM to about 100 mmPM, from about 60 mmPM to about 65 mmPM, from about 65 mmPM to about 70 mmPM, from about 70 mmPM to about 75 mmPM, from about 75 mmPM to about 80 mmPM, from about 80 mmPM to about 85 mmPM, or from about 85 mmPM to about 90 mmPM. The one or more fourth rotational speeds can be from about 800 RPM to about 2200 RPM, from about 1000 RPM to about 2000 RPM, from about 1200 RPM to about 1800 RPM, from about 1000 RPM to about 1200 RPM, from about 1200 RPM to about 1400 RPM, from about 1400 RPM to about 1600 RPM, from about 1500 RPM to about 1700 RPM, from about 1600 RPM to about 1800 RPM, from about 1700 RPM to about 1900 RPM, from about 1800 RPM to about 2000 RPM, from about 1300 RPM to about 1400 RPM, from about 1400 RPM to about 1500 RPM, from about 1500 RPM to about 1600 RPM, from about 1600 RPM to about 1700 RPM, or from about 1700 RPM to about 1800 RPM. Measured from a top of the preformed object 204, the fourth depth 238 can be from about 90% of the height 208 of the preformed object 204 within the die 206 to about 100% of the height 208, from about 91% of the height 208 to about 99% of the height 208, from about 92% of the height 208 to about 98% of the height 208, from about 90% of the height 208 to about 95% of the height 208, from about 95% of the height 208 to about 100% of the height, from about 90% of the height 208 to about 92% of the height 208, from about 92% of the height 208 to about 94% of the height 208, from about 94% of the height 208 to about 96% of the height 208, from about 96% of the height 208 to about 98% of the height 208, or from about 98% of the height 208 to about 100% of the height 208.

In one or more illustrative examples where a height 208 of the preformed object 204 is from about 20 mm to about 30 mm, the first depth 232 can be from about 0.5 mm to about 3 mm, the second depth 234 can be from about 3 mm to about 10 mm, the third depth 236 can be from about 12 mm to about 20 mm, and the fourth depth 238 can be from about 20 mm to about 30 mm.

After performing the protocol to produce the formed article 230, the tool 220 can be retracted and removed from the die 206. In one or more examples, the tool 220 can be retracted at vertical speeds from about 10 mmPM to about 200 mmPM, from about 20 mmPM to about 150 mmPM, from about 40 mmPM to about 120 mmPM, from about 20 mmPM to about 60 mmPM, from about 30 mmPM to about 70 mmPM, from about 40 mmPM to about 80 mmPM, from about 50 mmPM to about 90 mmPM, from about 60 mmPM to about 1000 mmPM, from about 20 mmPM to about 40 mmPM, from about 30 mmPM to about 50 mmPM, from about 40 mmPM to about 60 mmPM, from about 50 mmPM to about 70 mmPM, or from about 60 mmPM to about 80 mmPM. Additionally, the tool 220 can be retracted from the die 206 at rotational speeds from In at least some examples, during retraction of the tool 220 from the die 206, the tool 220 can be rotated in a direction opposite the direction that the tool 220 was rotated during entry of the tool 220 into the die 206. For example, in scenarios where the tool 220 was rotated in a counterclockwise direction while being moved into the die 206, the tool 220 can be rotated in a clockwise direction while being retracted from the die 206. Further, in situations where the tool 220 was rotated in a clockwise direction while being moved into the die 206, the tool 220 can be rotated in a counterclockwise direction while being retracted from the die 206.

The vertical and rotational motion of the tool 220 can cause the temperature of the preformed object 204 to increase. In one or more illustrative examples, the vertical motion and the rotational motion of the tool 220 can cause temperatures of the preformed object 204 to be from about 60% to about 90% of the melting temperature of the material comprising the preformed object 204, from about 65% to about 85% of the melting temperature of the material comprising the preformed object 204, from about 70% to about 90% of the melting temperature of the material comprising the preformed object 204, from about 70% to about 75% of the melting temperature of the material comprising the preformed object 204, from about 75% to about 80% of the melting temperature of the material comprising the preformed object 204, or from about 80% to about 85% of the melting temperature of the material comprising the preformed object 204. In scenarios where the preformed object 204 is comprised of an AA7075 aluminum alloy, the vertical motion and the rotational motion of the tool 220 can cause temperatures of the preformed object 204 to be from about 480° C. to about 550° C. or from about 500° C. to about 530° C. during at least the period of time when the tool 220 is moving from the first depth 232 to the fourth depth 238. Additionally, in scenarios where the preformed object 204 is comprised of an AZ31 magnesium alloy, the vertical motion and the rotational motion of the tool 220 can cause temperatures of the preformed object 204 to be from about 490° C. to about 560° C. or from about 510° C. to about 540° C. during at least the period of time when the tool 220 is moving from the first depth 232 to the fourth depth 238.

The rotational speeds and the vertical speeds of the tool 220 can be selected to cause the temperature of the preformed object 204 to be heated such that shearing can take place with respect particles of the preformed object 204. In one or more examples, the shearing can cause boundaries of the particles of the preformed object 204 to at least partially break and then bond to each other. In situations where the rotational speed of the tool 220 is too low and/or the temperature of the preformed object 204 is too low, the shearing may not take place and the improved physical properties of articles formed according to the implementations described herein may not be present. Additionally, in scenarios where the rotational speed of the tool 220 is too high and/or the temperature of the preformed object 204 is too high, voids may be created in the formed article 230 leading to properties of the formed article 230 that are not as improved in relation to the properties of articles 230 manufactured according to implementations described herein. In still other examples, the rotational speeds and vertical speeds of the tool 220 can be selected such that a force from about 50 kilonewtons (kN) to about 200 kN or from about 75 kN to about 150 kN is applied by the second shoulder 224 of the tool 220 onto the preformed object 204. In at least some examples, the second shoulder 222 can be configured to minimize the amount of material of the preformed object 204 being discharged as the tool 220 moves into the preformed object 204. Further, the vertical speed and rotational speed profile of the protocol for the tool 220 can be implemented such that the rotational speed from the top of the preformed object 204 to the first depth 232 is relatively slow in order to cause the tool 220 to enter the preformed object 204 without cause too much material of the preformed object 220 to be discharged and the rotational speed then increases from the first depth 232 to the end of the protocol in order to generate sufficient heat to cause the particles of the preformed object 204 to bond to one another.

The vertical motion and the rotational motion of the tool 220 can cause a hollow region 240 to be formed in the formed article 230. The hollow region 240 can have a diameter that corresponds to the diameter of the tool 220. In various examples, as the tool 220 is being pushed into the preformed object 204 and rotated, portions of the preformed object 204 are pushed into the protrusions 216 of the die 206 such that the shape of the formed article 230 corresponds to the pattern 212.

The formed article 230 can have the same or similar amounts of materials as the preformed object 204. That is, in various examples, chemical reactions taking place between components of the preformed object 204 are minimized or eliminated. Additionally, grain sizes of the formed article 230 can be less than the grain sizes of articles having similar shape and size and formed form the same or similar materials as the formed article 230 using existing processes. In one or more examples, grain sizes of the formed article 230 can be at least 1.5 times smaller, at least 2 times smaller, at least 2.5 times smaller, at least 3 times smaller, at least 3.5 times smaller, or at least 4 times smaller than grain sizes of articles produced using existing processes and having similar shape and size and formed form the same or similar materials as the article 230. In one or more illustrative examples, at least a portion of the formed article 230 can have grain sizes from about 3 micrometers (μm) to about 30 μm, from about 5 μm to about 25 μm, from about 8 μm to about 20 μm, from about 6 μm to about 12 μm, from about 8 μm to about 14 μm, from about 10 μm to about 16 μm, or from about 12 μm to about 18 μm.

FIG. 3 illustrates a framework 300 to produce an article using a die and a tool without threads, in accordance with one or more example implementations. The framework 300 can include, at 302, placing a powder 304 directly into a die 306. In one or more examples, the powder 304 can include at least one of one or more metallic materials. In at least some examples, the powder 304 can be comprised of aluminum. In various examples, the powder 304 can be comprised of an alloy of aluminum. For example, the powder 304 can be comprised of aluminum and at least one of silicon, iron, copper, manganese, magnesium, chromium, zinc, or titanium. In still other examples, the powder 304 can be comprised of iron or an alloy of iron. In one or more additional illustrative examples, the powder 304 can be comprised of an alloy of iron that includes at least one of silicon, manganese, or carbon.

The powder 304 can have particle sizes from about 0.5 μm to about 100 μm, from about 1 μm to about 80 μm, from about 5 μm to about 60 μm, from about 10 μm to about 50 μm, from about 1 μm to about 10 μm, from about 5 μm to about 15 μm, from about 10 μm to about 20 μm, from about 15 μm to about 25 μm, from about 20 μm to about 30 μm, from about 25 μm to about 35 μm, from about 30 μm to about 40 μm, from about 35 μm to about 45 μm, from about 40 μm to about 50 μm, from about 45 μm to about 55 μm, from about 50 μm to about 60 μm, from about 55 μm to about 65 μm, from about 60 μm to about 70 μm, from about 65 μm to about 75 μm, or from about 70 μm to about 80 μm.

The die 306 can have a pattern 308. In the illustrative examples of FIG. 3, the pattern 308 can have a circular shape. In one or more additional examples, the pattern 308 can have an elliptical shape. Although the illustrative example of FIG. 3 does not show the pattern 308 as having any protrusions extending from a center portion of the die, in other examples, the pattern 308 can that are different from a circular shape or an elliptical shape. In addition, the die 306 can be formed from at least one of at least one of carbon steel, tool steel, stainless steel, galvanized steel, nickel-chromium alloys. In one or more examples, the die 306 can have an open end in which the powder 304 is deposited and a bottom end that is at least partially closed. In one or more additional examples, the die 306 can have an open end in which the powder 304 is deposited and a bottom end that is also open.

The framework 300 can also include, at 310, inserting a tool 312 into the powder 304 disposed in the die 306. The tool 312 can include a first shoulder section 314 having a first diameter and a second shoulder section 316 having a second diameter that is smaller than the first diameter. The tool 312 can also include an extended member 318. The extended member 318 can be free of threads. The tool 312 can be formed from at least one of carbon steel, tool steel, stainless steel, galvanized steel, or nickel-chromium alloys. In one or more illustrative examples, the tool 312 can be comprised of H13 tool steel. The tool 312 can be moved in a vertical direction to contact the powder 304 disposed in the die 306. For example, the tool 312 can move downward to contact the powder 304 disposed in the die 306. Additionally, the tool 312 can move in a rotational direction. In one or more examples, the tool 312 can be rotated in a clockwise direction. In one or more additional examples, the tool 312 can be rotated in a counterclockwise direction.

At 320, the framework 300 can include performing a protocol using the tool 312 to produce a formed article 322. In one or more examples, the protocol can be implemented by a computing device that controls operation of the tool 312. In various examples, the computing device can execute software that causes the protocol to be implemented by one or more pieces of machinery. In at least some examples, the tool 312 can be part of a piece of machinery that can be used to position the die 306 and the tool 312 such that the extended member 318 of the tool 312 can be inserted into the powder 304 disposed in the die 306. The machinery can also cause at least one of the tool 312 or the die 306 to move in a vertical direction. In various examples, as the protocol is implemented, the powder 304 can be transformed to an object within the die 306 having at least a semi-solid state with a form that corresponds to the pattern 308 and, as the object within the die 306, the article 322 can become fully formed.

The protocol can indicate a vertical speed of the tool 312 and a rotational speed of the tool 312. The protocol can also indicate the vertical speed and the rotational speed of the tool 312 at one or more depths that the extended member 318 is inserted into the die 306. The protocol can indicate that the tool 312 is to have one or more first vertical speeds and one or more first rotational speeds until a first depth 324 and one or more second vertical speeds and one or more second rotational speeds until a second depth 326. In addition, the protocol can indicate that the tool 312 is to have one or more third vertical speeds and one or more third rotational speeds until the third depth 328 and one or more fourth vertical speeds and one or more fourth rotational speeds until the fourth depth 330. In at least some examples, the fourth depth 330 can correspond to a bottom end of the die 306.

In one or more illustrative examples, the one or more first vertical speeds can be from about 1 millimeters per minute (mmPM) to about 10 mmPM, from about 2 mmPM to about 8 mmPM, from about 3 mmPM to about 6 mmPM, from about 1 mmPM to about 3 mmPM, from about 2 mmPM to about 4 mmPM, from about 3 mmPM to about 5 mmPM, from about 1 mmPM to about 2 mmPM, from about 2 mmPM to about 3 mmPM, from about 3 mmPM to about 4 mmPM, from about 4 mmPM to about 5 mmPM, or from about 5 mmPM to about 6 mmPM. The one or more first rotational speeds can be from about 0.5 rotations per minute (RPM) to about 15 RPM, from about 0.8 RPM to about 12 RPM, from about 1 RPM to about 10 RPM, from about 2 RPM to about 8 RPM, from about 3 RPM to about 6 RPM, from about 0.5 RPM to about 2.5 RPM, from about 1 RPM to about 3 RPM, from about 1.5 RPM to about 3.5 RPM, from about 2 RPM to about 4 RPM, from about 2.5 RPM to about 4.5 RPM, from about 3 RPM to about 5 RPM, from about 0.5 RPM to about 1.5 RPM, from about 1 RPM to about 2 RPM, from about 1.5 RPM to about 2.5 RPM, or from about 2 RPM to about 3 RPM. Measured from a top of the powder 304, the first depth 324 can be from about 15% to about 40% of a height of the powder 304, from about 20% to about 35% of a height of the powder 304, from about 15% to about 25% of a height of the powder 304, from about 20% to about 30% of a height of the powder 304, from about 25% of to about 35% of a height of the powder 304, or from about 30% to about 40% of a height of the powder 304.

In one or more additional illustrative examples, the one or more second vertical speeds can be from about 0.3 mmPM to about 4 mmPM, from about 0.5 mmPM to about 3 mmPM, from about 0.8 mmPM to about 2 mmPM, from about 0.5 mmPM to about 1.5 mmPM, from about 1 mmPM to about 20 mmPM, from about 1.5 mmPM to about 2.5 mmPM, from about 2 mmPM to about 3 mmPM, or from about 3.5 mmPM to about 4 mmPM. The one or more second rotational speeds can be from about 0.5 rotations per minute (RPM) to about 15 RPM, from about 0.8 RPM to about 12 RPM, from about 1 RPM to about 10 RPM, from about 2 RPM to about 8 RPM, from about 3 RPM to about 6 RPM, from about 0.5 RPM to about 2.5 RPM, from about 1 RPM to about 3 RPM, from about 1.5 RPM to about 3.5 RPM, from about 2 RPM to about 4 RPM, from about 2.5 RPM to about 4.5 RPM, from about 3 RPM to about 5 RPM, from about 0.5 RPM to about 1.5 RPM, from about 1 RPM to about 2 RPM, from about 1.5 RPM to about 2.5 RPM, or from about 2 RPM to about 3 RPM. Measured from a top of the powder 304, the second depth 326 can be from about 25% to about 50% of a height of the powder 304, from about 30% to about 45% of a height of the powder 304, from about 35% to about 40% of a height of the powder 304, from about 35% to about 45% of a height of the powder 304, or from about 40% of to about 50% of a height of the powder 304.

In one or more further illustrative examples, the one or more third vertical speeds can be from about 0.3 mmPM to about 4 mmPM, from about 0.5 mmPM to about 3 mmPM, from about 0.8 mmPM to about 2 mmPM, from about 0.5 mmPM to about 1.5 mmPM, from about 1 mmPM to about 20 mmPM, from about 1.5 mmPM to about 2.5 mmPM, from about 2 mmPM to about 3 mmPM, or from about 3.5 mmPM to about 4 mmPM. The one or more third rotational speeds can be from about 30 RPM to about 250 RPM, from about 50 RPM to about 200 RPM, from about 50 RPM to about 100 RPM, from about 75 RPM to about 125 RPM, from about 100 RPM to about 150 RPM, from about 125 RPM to about 175 RPM, from about 150 RPM to about 200 RPM, from about 50 RPM to about 75 RPM, from about 75 RPM to about 100 RPM, from about 100 RPM to about 125 RPM, or from about 125 RPM to about 150 RPM. Measured from a top of the powder 304, the third depth 328 can be from about 40% to about 75% of a height of the powder 304, from about 50% to about 70% of a height of the powder 304, from about 50% to about 60% of a height of the powder 304, from about 55% to about 65% of a height of the powder 304, from about 60% to about 70% of a height of the powder 304, from about 65% to about 75% of a height of the powder 304, or from about 70% to about 75% of a height of the powder 304.

In still additional illustrative examples, the one or more fourth vertical speeds can be from about 0.3 mmPM to about 4 mmPM, from about 0.5 mmPM to about 3 mmPM, from about 0.8 mmPM to about 2 mmPM, from about 0.5 mmPM to about 1.5 mmPM, from about 1 mmPM to about 20 mmPM, from about 1.5 mmPM to about 2.5 mmPM, from about 2 mmPM to about 3 mmPM, or from about 3.5 mmPM to about 4 mmPM. The one or more fourth rotational speeds can be from about 30 RPM to about 250 RPM, from about 50 RPM to about 200 RPM, from about 50 RPM to about 100 RPM, from about 75 RPM to about 125 RPM, from about 100 RPM to about 150 RPM, from about 125 RPM to about 175 RPM, from about 150 RPM to about 200 RPM, from about 50 RPM to about 75 RPM, from about 75 RPM to about 100 RPM, from about 100 RPM to about 125 RPM, or from about 125 RPM to about 150 RPM. Measured from a top of the powder 304, the fourth depth 330 can be from about 90% to about 100% of a height of the powder 304, from about 91% to about 99% of a height of the powder 304, from about 92% to about 98% of a height of the powder 304, from about 90% to about 95% of a height of the powder 304, from about 95% to about 100% of a height of the powder 304, from about 90% to about 92% of a height of the powder 304, from about 92% to about 94% of a height of the powder 304, from about 94% of to about 96% of a height of the powder 304, from about 96% to about 98% of a height of the powder 304, or from about 98% to about 100% of a height of the powder 304.

In one or more illustrative examples where of a height of the powder 304 is from about 3 mm to about 6 mm, the first depth 324 can be from about 0.3 mm to about 1.5 mm, the second depth 326 can be from about 1.5 mm to about 2.5 mm, the third depth 328 can be from about 2.5 mm to about 3.5 mm, and the fourth depth 330 can be from about 3.5 mm to about 6 mm.

After performing the protocol to produce the formed article 322, the tool 312 can be retracted and removed from the die 306. In one or more examples, the tool 312 can be retracted at vertical speeds from about 10 mmPM to about 100 mmPM, from about 20 mmPM to about 80 mmPM, from about 30 mmPM to about 70 mmPM, from about 10 mmPM to about 30 mmPM, from about 20 mmPM to about 40 mmPM, from about 30 mmPM to about 50 mmPM, from about 10 mmPM to about 20 mmPM, from about 20 mmPM to about 30 mmPM, from about 30 mmPM to about 40 mmPM, or from about 40 mmPM to about 50 mmPM. Additionally, the tool 312 can be retracted from the die 306 at rotational speeds from about 10 mmPM to about 300 mmPM, from about 20 mmPM to about 250 mmPM, from about 40 mmPM to about 200 mmPM, from about 20 mmPM to about 60 mmPM, from about 30 mmPM to about 70 mmPM, from about 40 mmPM to about 80 mmPM, from about 50 mmPM to about 90 mmPM, from about 60 mmPM to about 100 mmPM, from about 100 mmPM to about 140 mmPM, from about 140 mmPM to about 180 mmPM, or from about 180 mmPM to about 220. In at least some examples, during retraction of the tool 312 from the die 306, the tool 312 can be rotated in a direction opposite the direction that the tool 312 was rotated during entry of the tool 312 into the die 306. For example, in scenarios where the tool 312 was rotated in a counterclockwise direction while being moved into the die 236, the tool 312 can be rotated in a clockwise direction while being retracted from the die 306. Further, in situations where the tool 312 was rotated in a clockwise direction while being moved into the die 306, the tool 312 can be rotated in a counterclockwise direction while being retracted from the die 306.

The vertical and rotational motion of the tool 312 can cause the temperature of the powder 304 and an object partially formed from the powder 304 disposed within the die 306 to increase. In one or more illustrative examples, the vertical motion and the rotational motion of the tool 312 can cause temperatures of the powder 304 and/or an object partially formed by the powder 304 to be from about 50% to about 90% of the melting temperature of the material comprising the powder 304, from about 55% to about 85% of the melting temperature of the material comprising the powder 304, from about 60% to about 80% of the melting temperature of the material comprising the powder 304, from about 50% to about 55% of the melting temperature of the material comprising the powder 304, from about 55% to about 60% of the melting temperature of the material comprising the powder 304, from about 60% to about 65% of the melting temperature of the material comprising the powder 304, from about 65% to about 70% of the melting temperature of the material comprising the powder 304, or from about 70% to about 75% of the melting temperature of the material comprising the powder 304. In scenarios where the powder 304 is comprised of an alloy of iron and silicon having no greater than 4% by weight silicon, the vertical motion and the rotational motion of the tool 312 can cause temperatures of the material disposed in the die 306 to be from about 875° C. to about 1000° C., from about 900° C. to about 975° C., or from about 925° C. to about 950° C. during at least the period of time when the tool 312 is moving from the first depth 324 to the fourth depth 330.

The rotational speeds and the vertical speeds of the tool 312 can be selected to cause the temperatures of the powder 304 and/or a partially formed object comprising the powder 304 disposed in the die 306 to be heated such that shearing can take place with respect particles of the powder 304. In one or more examples, the shearing can cause boundaries of the particles of the powder 304 to at least partially break and then bond to each other. In situations where the rotational speed of the tool 312 is too low and/or the temperature of material disposed in the die 306 is too low, the shearing may not take place and the improved physical properties of articles formed according to the implementations described herein may not be present. Additionally, in scenarios where the rotational speed of the tool 312 is too high and/or the temperature of the material disposed in the die 306 is too high, voids may be created in the formed article 322 leading to properties of the formed article 322 that are not as improved in relation to the properties of articles 322 manufactured according to implementations described herein. In still other examples, the rotational speeds and vertical speeds of the tool 312 can be selected such that a force from about 5 kilonewtons (kN) to about 150 kN, from about 10 kN to about 100 kN, from about 10 kN to about 20 kN, from about 20 kN to about 30 kN, from about 30 kN to about 40 kN, from about 40 kN to about 50 kN, from about 50 kN to about 60 kN, from about 60 kN to about 70 kN, or from about 70 kN to about 80 kN is applied by the second shoulder 316 of the tool 312 onto the material disposed in the die 306. In at least some examples, the first shoulder 314 can be configured to minimize the amount of material disposed in the die 306 from being discharged as the tool 312 moves into material disposed in the die 306. Further, the vertical speed and rotational speed profile of the protocol for the tool 312 can be implemented such that the rotational speed from the top of the material disposed in the die 306 to the first depth 324 is relatively fast and the rotational speed then decreases from the first depth 324 to the end of the protocol in order to generate sufficient heat to cause the particles of the powder 304 to bond to one another. The vertical motion and the rotational motion of the tool 312 can cause a hollow region 324 to be formed in the formed article 322. The hollow region 324 can have a diameter that corresponds to a diameter of the tool 312.

The formed article 322 can have the same or similar amounts of materials as the powder 304. That is, in various examples, chemical reactions taking place between components of powder 304 are minimized or eliminated. Additionally, grain sizes of the formed article 322 can be less than the grain sizes of articles having similar shape and size and formed form the same or similar materials as the formed article 322 using existing processes. In one or more examples, grain sizes of the formed article 322 can be at least 1.5 times smaller, at least 2 times smaller, at least 2.5 times smaller, at least 3 times smaller, at least 3.5 times smaller, or at least 4 times smaller than grain sizes of articles produced using existing processes and having similar shape and size and formed form the same or similar materials as the article 322. In one or more illustrative examples, at least a portion of the formed article 322 can have grain sizes from about 3 micrometers (m) to about m, from about 5 μm to about 25 μm, from about 8 μm to about 20 μm, from about 6 μm to about 12 μm, from about 8 μm to about 14 μm, from about 10 μm to about 16 μm, or from about 12 μm to about 18 μm.

FIG. 4 illustrates a first rotational tool 400 having a section that is fully threaded and a second rotational tool 402 having a section that is partially threaded, in accordance with one or more example implementations. The first rotational tool 400 can include a number of sections that are arranged serially along an axis. In one or more examples, the number of sections of the first rotational tool 400 can be formed from a single piece of material. In one or more additional examples, at least one of the sections of the first rotational tool 400 can be formed individually and joined to one or more additional sections of the first rotational tool 400. The first rotational tool 400 can be comprised of at least one of carbon steel, tool steel, stainless steel, galvanized steel, or nickel-chromium alloys. In one or more illustrative examples, the first rotational tool 402 can be comprised of H13 tool steel.

The first rotational tool 400 can include a first section 404 that can engage with machinery that is used to control movement of the first rotational tool 400 in at least one of a vertical direction, a horizontal direction, or a rotational direction. The first section 404 can have a length 406. The length 406 can be from about 4 centimeters (cm) to about 12 cm, from about 4 cm to about 10 cm, from about 4 cm to about 8 cm, from about 4 cm to about 6 cm, from about 6 cm to about 12 cm, from about 6 cm to about 10 cm, from about 6 cm to about 8 cm, from about 8 cm to about 12 cm, from about 8 cm to about 10 cm, or from about 10 cm to about 12 cm. The first section 404 can also have a width 408. The width 408 can be from about 1 cm to about 6 cm, from about 1 cm to about 5 cm, from about 1 cm to about 4 cm, from about 1 cm to about 3 cm, from about 1 cm to about 2 cm, from about 2 cm to about 6 cm, from about 2 cm to about 5 cm, from about 2 cm to about 4 cm, from about 2 cm to about 3 cm, from about 3 cm to about 6 cm, from about 3 cm to about 5 cm, from about 3 cm to about 4 cm, from about 4 cm to about 6 cm, from about 4 cm to about 5 cm, or from about 5 cm to about 6 cm.

The first rotational tool 400 can also include a second section including a first shoulder section 410 and a second shoulder section 412. The first shoulder section 410 can be configured to facilitate compaction of material disposed in a die and the second shoulder section 412 can be configured to minimize material being discharged from a die while the material is contacted with the first rotational tool 402. The first shoulder section 410 can have a length 414 and a width 416. The length 414 can be from about 0.5 cm to about 4 cm, from about 0.5 cm to about 3.5 cm, from about 0.5 cm to about 3 cm, from about 0.5 cm to about 2.5 cm, from about 0.5 cm to about 2 cm, from about 0.5 cm to about 1.5 cm, from about 0.5 cm to about 1 cm, from about 1 cm to about 4 cm, from about 1 cm to about 3.5 cm, from about 1 cm to about 3 cm, from about 1 cm to about 2.5 cm, from about 1 cm to about 2 cm, from about 1 cm to about 1.5 cm, from about 1.5 cm to about 4 cm, from about 1.5 cm to about 3.5 cm, from about 1.5 cm to about 3 cm, from about 1.5 cm to about 2.5 cm, from about 1.5 cm to about 2 cm, from about 2 cm to about 4 cm, from about 2 cm to about 3.5 cm, from about 2 cm to about 3 cm, from about 2 cm to about 2.5 cm, from about 2.5 cm to about 4 cm, from about 2.5 cm to about 3.5 cm, from about 2.5 cm to about 3 cm, from about 3 cm to about 4 cm, from about 3 cm to about 3.5 cm, or from about 3.5 cm to about 4 cm. The width 416 can be from about can be from about 1 cm to about 6 cm, from about 1 cm to about 5 cm, from about 1 cm to about 4 cm, from about 1 cm to about 3 cm, from about 1 cm to about 2 cm, from about 2 cm to about 6 cm, from about 2 cm to about 5 cm, from about 2 cm to about 4 cm, from about 2 cm to about 3 cm, from about 3 cm to about 6 cm, from about 3 cm to about 5 cm, from about 3 cm to about 4 cm, from about 4 cm to about 6 cm, from about 4 cm to about 5 cm, or from about 5 cm to about 6 cm.

The second shoulder section 412 can have a length 418 and a width 420. The length 418 can be from about 0.2 cm to about 1.5 cm, from about 0.2 cm to about 1.2 cm, from about 0.2 cm to about 1 cm, from about 0.2 cm to about 0.8 cm, from about 0.2 cm to about 0.5 cm, from about 0.5 cm to about 1.5 cm, from about 0.5 cm to about 1.2 cm, from about 0.5 cm to about 0.8 cm, from about 0.8 cm to about 1.5 cm, from about 0.8 cm to about 1.2 cm, from about 1 cm to about 1.5 cm, or from about 1.2 cm to about 1.5 cm. The width 420 can be from about 1 cm to about 6 cm, from about 1 cm to about 5 cm, from about 1 cm to about 4 cm, from about 1 cm to about 3 cm, from about 1 cm to about 2 cm, from about 2 cm to about 6 cm, from about 2 cm to about 5 cm, from about 2 cm to about 4 cm, from about 2 cm to about 3 cm, from about 3 cm to about 6 cm, from about 3 cm to about 5 cm, from about 3 cm to about 4 cm, from about 4 cm to about 6 cm, from about 4 cm to about 5 cm, or from about 5 cm to about 6 cm.

In addition, the first rotational tool 400 can include a third section 422. The third section 422 can be configured to bore into a preformed object. The preformed object can include billet comprised of one or more metallic materials. The third section 422 can have a number of threads 424. In one or more examples, the threads 424 can include right-handed threads. In one or more additional examples, the threads 424 can include left-handed threads. In various examples, the threads 424 can have a pitch from about 1 revolution to about 3 revolutions, from about 1 revolution to about 2.5 revolutions, from about 1 revolution to about 2 revolutions, from about 1 revolution to about 1.5 revolutions, from about 1.5 revolutions to about 3 revolutions, from about 1.5 revolutions to about 2.5 revolutions, from about 1.5 revolutions to about 2 revolutions, from about 2 revolutions to about 3 revolutions, from about 2 revolutions to about 2.5 revolutions, or from about 2.5 revolutions to about 3 revolutions. The threads can also have a height from about 0.1 cm to about 2 cm, from about 0.1 cm to about 1.5 cm, from about 0.1 cm to about 1 cm, from about 0.1 cm to about 0.5 cm, from about 0.3 cm to about 2 cm, from about 0.3 cm to about 1.5 cm, from about 0.3 cm to about 1 cm, from about 0.3 cm to about 0.5 cm, from about 0.5 cm to about 2 cm, from about 0.5 cm to about 1.5 cm, from about 0.5 cm to about 1 cm, from about 1 cm to about 2 cm, from about 1 cm to about 1.5 cm, or from about 1.5 cm to about 2 cm.

The third section 422 can have a length 426 and a width 428. The length 426 can be from about 0.5 cm to about 4 cm, from about 0.5 cm to about 3.5 cm, from about 0.5 cm to about 3 cm, from about 0.5 cm to about 2.5 cm, from about 0.5 cm to about 2 cm, from about 0.5 cm to about 1.5 cm, from about 0.5 cm to about 1 cm, from about 1 cm to about 4 cm, from about 1 cm to about 3.5 cm, from about 1 cm to about 3 cm, from about 1 cm to about 2.5 cm, from about 1 cm to about 2 cm, from about 1 cm to about 1.5 cm, from about 1.5 cm to about 4 cm, from about 1.5 cm to about 3.5 cm, from about 1.5 cm to about 3 cm, from about 1.5 cm to about 2.5 cm, from about 1.5 cm to about 2 cm, from about 2 cm to about 4 cm, from about 2 cm to about 3.5 cm, from about 2 cm to about 3 cm, from about 2 cm to about 2.5 cm, from about 2.5 cm to about 4 cm, from about 2.5 cm to about 3.5 cm, from about 2.5 cm to about 3 cm, from about 3 cm to about 4 cm, from about 3 cm to about 3.5 cm, or from about 3.5 cm to about 4 cm. Further, the width 428 can be from about from about 0.5 cm to about 4 cm, from about 0.5 cm to about 3.5 cm, from about 0.5 cm to about 3 cm, from about 0.5 cm to about 2.5 cm, from about 0.5 cm to about 2 cm, from about 0.5 cm to about 1.5 cm, from about 0.5 cm to about 1 cm, from about 1 cm to about 4 cm, from about 1 cm to about 3.5 cm, from about 1 cm to about 3 cm, from about 1 cm to about 2.5 cm, from about 1 cm to about 2 cm, from about 1 cm to about 1.5 cm, from about 1.5 cm to about 4 cm, from about 1.5 cm to about 3.5 cm, from about 1.5 cm to about 3 cm, from about 1.5 cm to about 2.5 cm, from about 1.5 cm to about 2 cm, from about 2 cm to about 4 cm, from about 2 cm to about 3.5 cm, from about 2 cm to about 3 cm, from about 2 cm to about 2.5 cm, from about 2.5 cm to about 4 cm, from about 2.5 cm to about 3.5 cm, from about 2.5 cm to about 3 cm, from about 3 cm to about 4 cm, from about 3 cm to about 3.5 cm, or from about 3.5 cm to about 4 cm.

The first rotational tool 400 can also have an overall length 430. The overall length 430 can be from about 5 cm to about 20 cm, from about 5 cm to about 18 cm, from about 5 cm to about 15 cm, from about 5 cm to about 12 cm, from about 5 cm to about 10 cm, from about 8 cm to about 20 cm, from about 8 cm to about 18 cm, from about 8 cm to about 15 cm, from about 8 cm to about 12 cm, from about 12 cm to about 16 cm, from about 16 cm to about 20 cm, from about 8 cm to about 10 cm, from about 10 cm to about 12 cm, from about 12 cm to about 14 cm, from about 14 cm to about 16 cm, from about 16 cm to about 18 cm, or from about 18 cm to about 20 cm.

Additionally, although not shown in the illustrative example of FIG. 4, the first rotational tool 400 can include a coolant receptable within the first section 404. The coolant receptable can hold an amount of coolant while the rotational tool 400 is being used to form one or more articles. The coolant receptacle can have a length from about 2 cm to about 10 cm, from about 2 cm to about 8 cm, from about 2 cm to about 4 cm, from about 4 cm to about 6 cm, from about 6 cm to about 8 cm, or from about 8 cm to about 10 cm. The coolant receptacle can also have a width from about 0.5 cm to about 4 cm, from about 0.5 cm to about 3.5 cm, from about 0.5 cm to about 3 cm, from about 0.5 cm to about 2.5 cm, from about 0.5 cm to about 2 cm, from about 0.5 cm to about 1.5 cm, from about 1 cm to about 4 cm, from about 1 cm to about 3.5 cm, from about 1 cm to about 3 cm, from about 1 cm to about 2.5 cm, or from about 1 cm to about 2 cm.

The second rotational tool 402 can include a first section 450 that can engage with machinery that is used to control movement of the second rotational tool 402 in at least one of a vertical direction, a horizontal direction, or a rotational direction. The first section 450 can have a length 452. The length 452 can be from about 4 cm to about 12 cm, from about 4 cm to about 10 cm, from about 4 cm to about 8 cm, from about 4 cm to about 6 cm, from about 6 cm to about 12 cm, from about 6 cm to about 10 cm, from about 6 cm to about 8 cm, from about 8 cm to about 12 cm, from about 8 cm to about 10 cm, or from about 10 cm to about 12 cm. The first section 450 can also have a width 454. The width 454 can be from about 1 cm to about 6 cm, from about 1 cm to about 5 cm, from about 1 cm to about 4 cm, from about 1 cm to about 3 cm, from about 1 cm to about 2 cm, from about 2 cm to about 6 cm, from about 2 cm to about 5 cm, from about 2 cm to about 4 cm, from about 2 cm to about 3 cm, from about 3 cm to about 6 cm, from about 3 cm to about 5 cm, from about 3 cm to about 4 cm, from about 4 cm to about 6 cm, from about 4 cm to about 5 cm, or from about 5 cm to about 6 cm.

The second rotational tool 402 can also include a second section including a first shoulder section 456 and a second shoulder section 458. The first shoulder section 456 can be configured to facilitate compaction of material disposed in a die and the second shoulder section 458 can be configured to minimize material being discharged from a die while the material is contacted with the second rotational tool 402. The first shoulder section 456 can have a length 460 and a width 462. The length 460 can be from about 0.5 cm to about 4 cm, from about 0.5 cm to about 3.5 cm, from about 0.5 cm to about 3 cm, from about 0.5 cm to about 2.5 cm, from about 0.5 cm to about 2 cm, from about 0.5 cm to about 1.5 cm, from about 0.5 cm to about 1 cm, from about 1 cm to about 4 cm, from about 1 cm to about 3.5 cm, from about 1 cm to about 3 cm, from about 1 cm to about 2.5 cm, from about 1 cm to about 2 cm, from about 1 cm to about 1.5 cm, from about 1.5 cm to about 4 cm, from about 1.5 cm to about 3.5 cm, from about 1.5 cm to about 3 cm, from about 1.5 cm to about 2.5 cm, from about 1.5 cm to about 2 cm, from about 2 cm to about 4 cm, from about 2 cm to about 3.5 cm, from about 2 cm to about 3 cm, from about 2 cm to about 2.5 cm, from about 2.5 cm to about 4 cm, from about 2.5 cm to about 3.5 cm, from about 2.5 cm to about 3 cm, from about 3 cm to about 4 cm, from about 3 cm to about 3.5 cm, or from about 3.5 cm to about 4 cm. The width 462 can be from about can be from about 1 cm to about 6 cm, from about 1 cm to about 5 cm, from about 1 cm to about 4 cm, from about 1 cm to about 3 cm, from about 1 cm to about 2 cm, from about 2 cm to about 6 cm, from about 2 cm to about 5 cm, from about 2 cm to about 4 cm, from about 2 cm to about 3 cm, from about 3 cm to about 6 cm, from about 3 cm to about 5 cm, from about 3 cm to about 4 cm, from about 4 cm to about 6 cm, from about 4 cm to about 5 cm, or from about 5 cm to about 6 cm.

The second shoulder section 458 can have a length 464 and a width 466. The length 458 can be from about 0.2 cm to about 1.5 cm, from about 0.2 cm to about 1.2 cm, from about 0.2 cm to about 1 cm, from about 0.2 cm to about 0.8 cm, from about 0.2 cm to about 0.5 cm, from about 0.5 cm to about 1.5 cm, from about 0.5 cm to about 1.2 cm, from about 0.5 cm to about 0.8 cm, from about 0.8 cm to about 1.5 cm, from about 0.8 cm to about 1.2 cm, from about 1 cm to about 1.5 cm, or from about 1.2 cm to about 1.5 cm. The width 466 can be from about 1 cm to about 6 cm, from about 1 cm to about 5 cm, from about 1 cm to about 4 cm, from about 1 cm to about 3 cm, from about 1 cm to about 2 cm, from about 2 cm to about 6 cm, from about 2 cm to about 5 cm, from about 2 cm to about 4 cm, from about 2 cm to about 3 cm, from about 3 cm to about 6 cm, from about 3 cm to about 5 cm, from about 3 cm to about 4 cm, from about 4 cm to about 6 cm, from about 4 cm to about 5 cm, or from about 5 cm to about 6 cm.

In addition, the second rotational tool 402 can include a third section 468. The third section 468 can be configured to bore into a preformed object. The preformed object can include a billet comprised of one or more metallic materials. The third section 468 can have a number of threads 470. In one or more examples, the threads 470 can include right-handed threads. In one or more additional examples, the threads 470 can include left-handed threads. The third section 468 can be partially threaded such that the third section 468 is comprised of one or more threaded regions and one or more additional regions 472 that are free of threads 470. In various examples, the threads 470 can have a pitch from about 1 revolution to about 3 revolutions, from about 1 revolution to about 2.5 revolutions, from about 1 revolution to about 2 revolutions, from about 1 revolution to about 1.5 revolutions, from about 1.5 revolutions to about 3 revolutions, from about 1.5 revolutions to about 2.5 revolutions, from about 1.5 revolutions to about 2 revolutions, from about 2 revolutions to about 3 revolutions, from about 2 revolutions to about 2.5 revolutions, or from about 2.5 revolutions to about 3 revolutions. The threads 470 can also have a height from about 0.1 cm to about 2 cm, from about 0.1 cm to about 1.5 cm, from about 0.1 cm to about 1 cm, from about 0.1 cm to about 0.5 cm, from about 0.3 cm to about 2 cm, from about 0.3 cm to about 1.5 cm, from about 0.3 cm to about 1 cm, from about 0.3 cm to about 0.5 cm, from about 0.5 cm to about 2 cm, from about 0.5 cm to about 1.5 cm, from about 0.5 cm to about 1 cm, from about 1 cm to about 2 cm, from about 1 cm to about 1.5 cm, or from about 1.5 cm to about 2 cm.

The third section 468 can have a length 474 and a width 476. The length 474 can be from about 0.5 cm to about 4 cm, from about 0.5 cm to about 3.5 cm, from about 0.5 cm to about 3 cm, from about 0.5 cm to about 2.5 cm, from about 0.5 cm to about 2 cm, from about 0.5 cm to about 1.5 cm, from about 0.5 cm to about 1 cm, from about 1 cm to about 4 cm, from about 1 cm to about 3.5 cm, from about 1 cm to about 3 cm, from about 1 cm to about 2.5 cm, from about 1 cm to about 2 cm, from about 1 cm to about 1.5 cm, from about 1.5 cm to about 4 cm, from about 1.5 cm to about 3.5 cm, from about 1.5 cm to about 3 cm, from about 1.5 cm to about 2.5 cm, from about 1.5 cm to about 2 cm, from about 2 cm to about 4 cm, from about 2 cm to about 3.5 cm, from about 2 cm to about 3 cm, from about 2 cm to about 2.5 cm, from about 2.5 cm to about 4 cm, from about 2.5 cm to about 3.5 cm, from about 2.5 cm to about 3 cm, from about 3 cm to about 4 cm, from about 3 cm to about 3.5 cm, or from about 3.5 cm to about 4 cm. Further, the width 476 can be from about from about 0.5 cm to about 4 cm, from about 0.5 cm to about 3.5 cm, from about 0.5 cm to about 3 cm, from about 0.5 cm to about 2.5 cm, from about 0.5 cm to about 2 cm, from about 0.5 cm to about 1.5 cm, from about 0.5 cm to about 1 cm, from about 1 cm to about 4 cm, from about 1 cm to about 3.5 cm, from about 1 cm to about 3 cm, from about 1 cm to about 2.5 cm, from about 1 cm to about 2 cm, from about 1 cm to about 1.5 cm, from about 1.5 cm to about 4 cm, from about 1.5 cm to about 3.5 cm, from about 1.5 cm to about 3 cm, from about 1.5 cm to about 2.5 cm, from about 1.5 cm to about 2 cm, from about 2 cm to about 4 cm, from about 2 cm to about 3.5 cm, from about 2 cm to about 3 cm, from about 2 cm to about 2.5 cm, from about 2.5 cm to about 4 cm, from about 2.5 cm to about 3.5 cm, from about 2.5 cm to about 3 cm, from about 3 cm to about 4 cm, from about 3 cm to about 3.5 cm, or from about 3.5 cm to about 4 cm.

The second rotational tool 402 can also have an overall length 478. The overall length 478 can be from about 5 cm to about 20 cm, from about 5 cm to about 18 cm, from about 5 cm to about 15 cm, from about 5 cm to about 12 cm, from about 5 cm to about 10 cm, from about 8 cm to about 20 cm, from about 8 cm to about 18 cm, from about 8 cm to about 15 cm, from about 8 cm to about 12 cm, from about 12 cm to about 16 cm, from about 16 cm to about 20 cm, from about 8 cm to about 10 cm, from about 10 cm to about 12 cm, from about 12 cm to about 14 cm, from about 14 cm to about 16 cm, from about 16 cm to about 18 cm, or from about 18 cm to about 20 cm.

Additionally, although not shown in the illustrative example of FIG. 4, the second rotational tool 402 can include a coolant receptable within the first section 450. The coolant receptable can hold an amount of coolant while the rotational tool 402 is being used to form one or more articles. The coolant receptacle can have a length from about 2 cm to about 10 cm, from about 2 cm to about 8 cm, from about 2 cm to about 4 cm, from about 4 cm to about 6 cm, from about 6 cm to about 8 cm, or from about 8 cm to about 10 cm. The coolant receptacle can also have a width from about 0.5 cm to about 4 cm, from about 0.5 cm to about 3.5 cm, from about 0.5 cm to about 3 cm, from about 0.5 cm to about 2.5 cm, from about 0.5 cm to about 2 cm, from about 0.5 cm to about 1.5 cm, from about 1 cm to about 4 cm, from about 1 cm to about 3.5 cm, from about 1 cm to about 3 cm, from about 1 cm to about 2.5 cm, or from about 1 cm to about 2 cm.

FIG. 5 illustrates a third rotational tool 500 including a section in which no threads are present and illustrates an example die 550, in accordance with one or more example implementations. The third rotational tool 500 can include a first section 502 that can engage with machinery that is used to control movement of the third rotational tool 500 in at least one of a vertical direction, a horizontal direction, or a rotational direction. The first section 502 can have a length 504. The length 504 can be from about 4 cm to about 12 cm, from about 4 cm to about 10 cm, from about 4 cm to about 8 cm, from about 4 cm to about 6 cm, from about 6 cm to about 12 cm, from about 6 cm to about 10 cm, from about 6 cm to about 8 cm, from about 8 cm to about 12 cm, from about 8 cm to about 10 cm, or from about 10 cm to about 12 cm. The first section 502 can also have a width 506. The width 506 can be from about 1 cm to about 8 cm, from about 1 cm to about 6 cm, from about 1 cm to about 5 cm, from about 1 cm to about 4 cm, from about 1 cm to about 3 cm, from about 2 cm to about 6 cm, from about 2 cm to about 5 cm, from about 2 cm to about 4 cm, from about 2 cm to about 3 cm, from about 3 cm to about 6 cm, from about 3 cm to about 5 cm, from about 3 cm to about 4 cm, from about 4 cm to about 6 cm, from about 4 cm to about 5 cm, or from about 5 cm to about 6 cm.

The third rotational tool 500 can also include a second section including a first shoulder section 508 and a second shoulder section 510. The first shoulder section 508 can be configured to minimize material being discharged from a die while the material is contacted with the third rotational tool 500 and the second shoulder section 412 can be configured to facilitate compaction of material, such as a powder, disposed in a die. The first shoulder section 508 can have a length 512 and a width 514. The length 512 can be from about 0.5 cm to about 4 cm, from about 0.5 cm to about 3.5 cm, from about 0.5 cm to about 3 cm, from about 0.5 cm to about 2.5 cm, from about 0.5 cm to about 2 cm, from about 0.5 cm to about 1.5 cm, from about 0.5 cm to about 1 cm, from about 1 cm to about 4 cm, from about 1 cm to about 3.5 cm, from about 1 cm to about 3 cm, from about 1 cm to about 2.5 cm, from about 1 cm to about 2 cm, from about 1 cm to about 1.5 cm, from about 1.5 cm to about 4 cm, from about 1.5 cm to about 3.5 cm, from about 1.5 cm to about 3 cm, from about 1.5 cm to about 2.5 cm, from about 1.5 cm to about 2 cm, from about 2 cm to about 4 cm, from about 2 cm to about 3.5 cm, from about 2 cm to about 3 cm, from about 2 cm to about 2.5 cm, from about 2.5 cm to about 4 cm, from about 2.5 cm to about 3.5 cm, from about 2.5 cm to about 3 cm, from about 3 cm to about 4 cm, from about 3 cm to about 3.5 cm, or from about 3.5 cm to about 4 cm. The width 514 can be from about can be from about 3 cm to about 15 cm, from about 3 cm to about 10 cm, from about 3 cm to about 8 cm, from about 4 cm to about 12 cm, from about 4 cm to about 10 cm, from about 4 cm to about 8 cm, from about 6 cm to about 12 cm, from about 6 cm to about 10 cm, or from about 8 cm to about 12 cm.

The second shoulder section 510 can have a length 516 and a width 518. The length 516 can be from about 0.5 cm to about 4 cm, from about 0.5 cm to about 3.5 cm, from about 0.5 cm to about 3 cm, from about 0.5 cm to about 2.5 cm, from about 0.5 cm to about 2 cm, from about 0.5 cm to about 1.5 cm, from about 0.5 cm to about 1 cm, from about 1 cm to about 4 cm, from about 1 cm to about 3.5 cm, from about 1 cm to about 3 cm, from about 1 cm to about 2.5 cm, from about 1 cm to about 2 cm, from about 1 cm to about 1.5 cm, from about 1.5 cm to about 4 cm, from about 1.5 cm to about 3.5 cm, from about 1.5 cm to about 3 cm, from about 1.5 cm to about 2.5 cm, from about 1.5 cm to about 2 cm, from about 2 cm to about 4 cm, from about 2 cm to about 3.5 cm, from about 2 cm to about 3 cm, from about 2 cm to about 2.5 cm, from about 2.5 cm to about 4 cm, from about 2.5 cm to about 3.5 cm, from about 2.5 cm to about 3 cm, from about 3 cm to about 4 cm, from about 3 cm to about 3.5 cm, or from about 3.5 cm to about 4 cm. The width 518 can be from about 3 cm to about 12 cm, from about 3 cm to about 10 cm, from about 3 cm to about 8 cm, from about 4 cm to about 12 cm, from about 4 cm to about 10 cm, from about 4 cm to about 8 cm, from about 6 cm to about 12 cm, or from about 6 cm to about 10 cm.

In addition, the third rotational tool 500 can include a third section 520. The third section 520 can be configured to bore into a powder disposed in a die. The third section 422 can be free of threads. The third section 520 can have a length 522 and a width 524. The length 522 can be from about 0.5 cm to about 4 cm, from about 0.5 cm to about 3.5 cm, from about 0.5 cm to about 3 cm, from about 0.5 cm to about 2.5 cm, from about 0.5 cm to about 2 cm, from about 0.5 cm to about 1.5 cm, from about 0.5 cm to about 1 cm, from about 1 cm to about 4 cm, from about 1 cm to about 3.5 cm, from about 1 cm to about 3 cm, from about 1 cm to about 2.5 cm, from about 1 cm to about 2 cm, from about 1 cm to about 1.5 cm, from about 1.5 cm to about 4 cm, from about 1.5 cm to about 3.5 cm, from about 1.5 cm to about 3 cm, from about 1.5 cm to about 2.5 cm, from about 1.5 cm to about 2 cm, from about 2 cm to about 4 cm, from about 2 cm to about 3.5 cm, from about 2 cm to about 3 cm, from about 2 cm to about 2.5 cm, from about 2.5 cm to about 4 cm, from about 2.5 cm to about 3.5 cm, from about 2.5 cm to about 3 cm, from about 3 cm to about 4 cm, from about 3 cm to about 3.5 cm, or from about 3.5 cm to about 4 cm. Further, the width 524 can be from about from about 0.3 cm to about 2 cm, from about 0.3 cm to about 1.5 cm, from about 0.3 cm to about 1 cm, from about 0.5 cm to about 2 cm, from about 0.5 cm to about 1.5 cm, from about 0.5 cm to about 1 cm, from about 1 cm to about 3 cm, or from about 1 cm to about 1.5 cm.

The third rotational tool 500 can also have an overall length 526. The overall length 526 can be from about 5 cm to about 20 cm, from about 5 cm to about 18 cm, from about 5 cm to about 15 cm, from about 5 cm to about 12 cm, from about 5 cm to about 10 cm, from about 8 cm to about 20 cm, from about 8 cm to about 18 cm, from about 8 cm to about 15 cm, from about 8 cm to about 12 cm, from about 12 cm to about 16 cm, from about 16 cm to about 20 cm, from about 8 cm to about 10 cm, from about 10 cm to about 12 cm, from about 12 cm to about 14 cm, from about 14 cm to about 16 cm, from about 16 cm to about 18 cm, or from about 18 cm to about 20 cm.

Additionally, although not shown in the illustrative example of FIG. 5, the third rotational tool 500 can include a coolant receptable within the first section 502. The coolant receptable can hold an amount of coolant while the rotational tool 500 is being used to form one or more articles. The coolant receptacle can have a length from about 2 cm to about 10 cm, from about 2 cm to about 8 cm, from about 2 cm to about 4 cm, from about 4 cm to about 6 cm, from about 6 cm to about 8 cm, or from about 8 cm to about 10 cm. The coolant receptacle can also have a width from about 0.5 cm to about 4 cm, from about 0.5 cm to about 3.5 cm, from about 0.5 cm to about 3 cm, from about 0.5 cm to about 2.5 cm, from about 0.5 cm to about 2 cm, from about 0.5 cm to about 1.5 cm, from about 1 cm to about 4 cm, from about 1 cm to about 3.5 cm, from about 1 cm to about 3 cm, from about 1 cm to about 2.5 cm, or from about 1 cm to about 2 cm.

The example die 550 of FIG. 5 can be used to produce an article having a pattern 552. The pattern 552 can include a circular center region 554 and a number of protrusions 556. In the illustrative example of FIG. 5, the die 550 has 14 protrusions. In other examples, the die 500 can have a greater number of protrusions or fewer protrusions. The pattern 552 can also include a ring 558 that encircles the center region 554 and into which the protrusions 556 extend. In various examples, the die 550 can be comprised of one or more metallic materials. For example, the die can be comprised of at least one of carbon steel, tool steel, stainless steel, galvanized steel, or nickel-chromium alloys.

The pattern 552 can have a diameter 560 that represents a farthest distance extending from the tip of a first protrusion to a tip of second protrusion disposed opposite the first protrusion. In one or more examples, the diameter 560 can be from about 0.5 cm to about 12 cm, from about 2 cm to about 10 cm, from about 2 cm to about 8 cm, from about 2 cm to about 6 cm, from about 2 cm to about 4 cm, from about 4 cm to about 12 cm, from about 4 cm to about 10 cm, from about 4 cm to about 8 cm, from about 4 cm to about 6 cm, from about 6 cm to about 12 cm, from about 6 cm to about 10 cm, from about 6 cm to about 8 cm, from about 8 cm to about 12 cm, or from about 8 cm to about 10.

The ring 558 can also include a diameter 562. The diameter 562 can be from about 3 cm to about 15 cm, from about 3 cm to about 12 cm, from about 3 cm to about 10 cm, from about 3 cm to about 8 cm, from about 3 cm to about 5 cm, from about 5 cm to about 15 cm, from about 5 cm to about 12 cm, from about 5 cm to about 10 cm, from about 5 cm to about 8 cm, from about 7 cm to about 15 cm, from about 7 cm to about 12 cm, from about 7 cm to about 10 cm, from about 10 cm to about 15 cm, from about 10 cm to about 12 cm, or from about 12 cm to about 15 cm. In various examples, the diameter 560 and the diameter 562 can be designed such that an article formed having the shape of the pattern 552 can have mechanical stability. That is, the diameter 560 and the diameter 562 can be designed such that the ring 558 is not too thin and may cause an article formed using the die 550 to easily break.

In addition, the die 550 can have an overall diameter 564. The overall diameter 564 can be from about 5 cm to about 20 cm, from about 5 cm to about 18 cm, from about 5 cm to about 15 cm, from about 5 cm to about 12 cm, from about 5 cm to about 10 cm, from about 8 cm to about 20 cm, from about 8 cm to about 18 cm, from about 8 cm to about 15 cm, from about 8 cm to about 12 cm, from about 10 cm to about 20 cm, from about 10 cm to about 18 cm, from about 10 cm to about 15 cm, from about 12 cm to about 20 cm, from about 12 cm to about 18 cm, from about 12 cm to about 15 cm, from about 15 cm to about 20 cm, or from about 15 cm to about 18 cm.

Although not shown in the illustrative example of FIG. 5, the die 550 can have a height that is from about 0.5 cm to about 10 cm, from about 0.5 cm to about 8 cm, from about 0.5 cm to about 5 cm, from about 0.5 cm to about 2 cm, from about 2 cm to about 10 cm, from about 2 cm to about 8 cm, from about 2 cm to about 5 cm, from about 4 cm to about 10 cm, from about 4 cm to about 8 cm, or from about 6 cm to about 10 cm.

Experimental Example
1. Introduction

Satisfying the increasing demand of electric vehicles (EV's) and reduce the carbon footprint from the automotive industries could only be possible through the use of light weight components and alternate innovative manufacturing technologies. As an example, cast iron and steel have been viably replaced with aluminum for engine blocks over the years. High strength aluminum alloys, magnesium, and nonferrous based metal matrix composites (MMCs) are the lightest class of structural metallic materials, making them very attractive for several applications. However, a wide range of applications of high strength 7xxx aluminum and magnesium (Mg) alloys are constricted owing to their poor workability/formability where specific components/complicated design parts are needed. To date, warm forming, casting, and hot forging are the only ways to attain a certain shape for high strength Al, Mg, and MMCs. Gear manufacturing, in particular, consists of several conventional processes like direct casting, molding, drawing, extrusion, forging. While these processes are efficient and fast, they involve several sub-steps, including machining, for roughing and finishing the final products. These post processing steps such as machining become challenging especially in fabricating MMC components. As an alternative, most popular way to manufacture gears is through powder metallurgy route. However, sintering step in the powder metallurgy route is high temperature, slow and the process depends on high quality powder feedstock. Therefore, there is a need for high-speed, near net-shape processes to produce gears (or other complex shapes) from the poor workability lightweight materials. For increased sustainability, these processes should also be flexible in the starting feedstock and accept both powder and bulk forms and rely less on lengthy high temperature processing steps.

Friction stir processing (FSP) and shear-assisted manufacturing technologies, including friction stir forming, friction extrusion, and Shear Assisted Processing and Extrusion (ShAPE™), have the capability to generate local heating by friction to overcome the poor ductility and process/extrude different grades of high-strength aluminum and magnesium alloys. Friction stir assisted simultaneous forging and joining (a derivative of FSP) was demonstrated by Hong et al. Hong, Mondal, and Das et al. demonstrated an Al/Mg bimetallic ring component by the friction stir forging method (FSF). The authors noticed that during FSF, the frictional heat and stirring of the rotating tool forge the blank, while simultaneously forming a solid-state joint between the Mg core and the Al skin, without additional external heating. Ohashi et al. demonstrated the formation of an A5083P-O aluminum alloy plate gear rack using the friction stir process while the stainless-steel backing block as a die with threads. However, the authors observed tunnel defects and non-uniform material flow even in the seam position.

The intense plastic deformation and local heating in friction-based processing can be helpful in obtaining complex shapes from the low workability metals. We hypothesize that aluminum and magnesium-based materials can be plasticized by the frictional heat at a lower temperature and simultaneously forged into a complex shape by the rotation and plunging action of a friction stir tool. This process would then be as fast as conventional forging but without preheating of the workpiece. The intense shear deformation would also result in dynamic recrystallization and mixing action to refine the microstructures, develop non-conventional textures, and enable distribution of the rein-forcing particles for the composite application, all of which may not be possible with the conventional processes.

In this present study, we have used FSF as an in-situ method that can induce large plastic strains at high strain rates to increase the temperature of the workpiece and to enable suitable conditions for forging complex shapes. During the iterative process development of I-FSF, we determined that the process is robust in terms of starting material (either solid billet or powder precursor) and can fabricate a near-net shape component/gear in a single step without any external source of heating. To better understand the evolution of material flow, strain, and temperature during the FSF process, as well as their correlations with the final material microstructure, a 3D, thermo-mechanically coupled simulation is carried out based on the smoothed particle hydrodynamics (SPH) method. Electron backscatter diffraction (EBSD) analysis has been performed at the core and gear teeth to determine the grain size, texture, and flow pattern.

2. Experimental Procedure
2.1 Materials

AA 7075-T6 (procured from McMaster-Carr) and AZ31 Mg (procured from Metal Mart International Inc.) were used in billet form with a diameter of 32 mm and height of 21 mm. For the MMC gear, AA5083 (procured from Stanford Advanced Materials) and 10 vol % of titanium diboride alloy powder (TiB₂) (procured form US research Nano-materials, Inc., 3 m) were used as the starting materials.

2.2 Experimental Methodology

I-FSF work was performed in position control mode in an ultra-high precision FSW machine located at Pacific Northwest National Laboratory (PNNL). FIG. 6 illustrates the step-by-step I-FSF process. The process is initiated by inserting a solid billet in a hollow die, then clamping it properly to the work deck, followed by plunging and forging to the desired shape as shown in the images in FIG. 8 sections a-a5. A friction stir welding (FSW) tool made of hardened H13 tool steel, consisting of a flat shoulder (dia. 32 mm) and 3 flat threaded pins (dia. 19 mm) was used for the forging process. For AZ31 Mg and AA 7075-T6, the tool used rotation speeds of 1700 and 1500 rpm and forging speeds of 75 and 50 mm/min, respectively. FIG. 8 section (b) shows a representative successful demonstration of 14-tooth spur gears fabricated out of AZ31Mg and AA 7075-T6. During the I-FSF process, we observed some formation of flash due to back-extrusion during the forging process. However, the formation of flash could be minimized with more precise tooling and die design.

2.3 Characterization

All samples present in this study were prepared through standard metallographic procedures beginning with grinding with SiC 220-1000 grit, followed by 6 μm, 1 μm alumina polish and finally a 0.05 μm colloidal silica vibratory polish for 2-3 h for SEM and EBSD analysis. The microstructures were studied via electron backscatter diffraction (EBSD) using a JEOL-7600 FESEM equipped with an Oxford Instruments Symmetry detector. Mapping was done using an accelerating voltage of 20 kV, a tilt angle of 70.0° and a working distance of ˜24 mm.

Data collection was accomplished with the Oxford AZtec acquisition software. AZtec Crystal was used for data analysis and cleanup first removing mis-indexed electron backscatter patterns and then performing an iterative zero solution extrapolation to a medium level.

2.4 SPH Model Set Up

Better predictions of material flow pattern, material mixture, stress-strain states, strain rate, and temperature evolution during the I-FSF process are crucial to understanding this complicated solid-phase processing (SPP) more effectively, and numerical simulation is the best way to achieve that at lower cost. Plenty of models have been proposed for various SPP techniques, such as FSP, FSW, and friction extrusion. In terms of governing equations, the existing models can be broadly categorized into solid-based and fluid-based methods. Solid-based models consider the workpiece as a viscoplastic or thermo-viscoplastic solid while fluid-based models treat the workpiece as a non-Newtonian fluid and relate fluid viscosity with workpiece material strength. Both models are demonstrated to be able to predict field variables with reasonable accuracy. In terms of domain discretization, the existing models can be classified into mesh-based and meshfree methods. Lagrangian, Eulerian, and arbitrary Lagrangian Eulerian methods are mesh-based methods that have demonstrated the capability to predict various field variables for SPP. One major disadvantage of mesh-based methods is the mesh distortion issue under extremely large material deformation, which usually happens during SPP. As a result, only a short processing time can be simulated by mesh-based methods to keep the material deformation within an acceptable range. As one of the meshfree methods, SPH is a Lagrangian particle method first invented by Lucy and Gingold and Monaghan for astrophysics simulations. Due to its meshfree nature, SPH is capable of handling extremely large material deformations and mixing, which would cause severe mesh distortion issues in mesh-based methods. The particle representation in SPH also enables a natural description of material interfaces, free surfaces, and moving boundaries during the simulation process, which is a challenging task for mesh-based methods. Due to these advantages, SPH has been used for many SPPs such as FSW and additive friction stir-deposition. Recently, Li et al. proposed a 3D thermomechanical coupled SPH model to predict mate-rial flow, strain, temperature, and extrusion force for friction extrusion of aluminum wires. The model is validated thoroughly by experimental data. Later, they extended the SPH model for ShAPE for aluminum tubes. As to work using SPH to simulate I-FSF, no studies have apparently been published yet.

The SPH model setup is detailed in FIG. 6 section a, in which the rotating and plunging tool and the 3 fixed 14-tooth hollow die are assumed as H13 rigid solids, while the AZ31 magnesium billet is deformable and discretized into 135,576 SPH particles. Johnson-Cook (J-C) constitutive relation is used to model the thermo-viscoplastic behavior of AZ31 during FSF. The J-C parameters A=163 MPa, B=n=0, C=0.016, M=1.829 with room temperature Tr=24° C. and melting temperature Tm=630° C. are used to address the non-saturating strain hardening issue during severe plastic deformations (SPDs). The frictional coefficient between rigid solids and SPH particles is set at 0.4. All the frictional sliding energy and 90% of the billet plastic deformation are converted to heat. The heat capacity and thermal conductivity of the AZ31 billet are set at 1000 J/Kg·° C. and 96 W/m·° C., respectively. For modeling I-FSF of AA7075, the same SPH model setup (135,576 SPH particles) is used, but with AA7075 J-C material parameters of A=515 MPa, B=n=0, C=0.024, M=0.35 with room temperature Tr=24° C. and melting temperature Tm=635° C. Frictional coefficient between rigid solids and SPH particles is set at 0.4. The heat capacity and thermal conductivity of the AA7075 billet are set at 960 J/Kg·° C. and 147 W/m·° C., respectively. The rotational and plunging speeds are set to be the same as the corresponding experimental setups. Both SPH models were validated by the temperature measured by the K-type thermocouple placed in the center of tool shoulder surface, where 510°-520° C. was predicted for Mg and 500-510° C. was predicted for Al at the final stage of the forging.

3. Results and Discussion
3.1 AZ31 Mg Gear Fabrication and Characterization

An optical macrograph of a FSFed 14-tooth AZ31 Mg spur gear is shown in FIG. 7 section (a). A characteristic radial material flow pattern is noticeable near the tooth region for all 14 teeth of the gear (FIG. 7 section (b)) (marked with blue dotted line). SPH simulation results representing the 14-tooth gear morphology with plastic strain, strain rate, and temperature distributions at the end of I-FSF is shown in FIG. 8 sections (a), (b, b1), and (c, c1), respectively. Because of the meshfree nature, SPH method was able to model this extreme material deformation scenario without mesh distortion issue. As compared to conventional forming process based on the SPH simulations it was noted that the effective plastic strain ranged from 107% on the bottom of the teeth tip to 3920% (there is a wide range of variation due to considering several points including the gear tooth edges etc.). This maximum strain and strain rate (4.17 s⁻¹) were observed where the pin of the tool interacted with the material around the stir zone (near core), where the tool and billet are in direct contact with each other in FIG. 8 section (a). Strain rate is comparatively less (with a minimum value of 4.69 s⁻¹) in the materials that are closer to the die, i.e., the teeth region (FIG. 8 section (b1)). A temperature gradient exists in the whole cross-section in FIG. 8 section (c), in which the core regime shows relatively higher temperature (˜570° C.) than the teeth crown regime (˜520° C.) (FIG. 8 section (c1)). This is obvious as more heat is generated by the tool shoulder on the top of the billet. However, the overall temperature in the gear center is around 480 to 540 mC with the amount of effective plastic strain (FIG. 8 section (a)). To visualize the material flow in the X-Y plane of the gear. It is observed that the material points at the gear teeth shank have very little displacement (0.416 mm) from their original locations, while the material points in the gear teeth travel farther from their original locations (4.511 mm, 9.84× more), indicating the material movement toward the deformation direction. The highest displacement point is close to tool/billet contacting surface, with a maximum value of 15.623 mm (36.56× more). A microhardness map exhibits slightly higher hardness in the teeth crown region compared to the core (FIG. 8 section (d)).

TABLE 1

Grain Size, HAGB and LAGB fractions for

AZ31 Mg and 7075-T6 gear

Grain
HAGB
LAGB

Location
size (μm)
fraction (%)
fraction (%)

AZ31 Mg

Tip
12.4 ± 9.4
56.1
43.9

Mid-section
12.6 ± 9.8
58.9
41.1

Root
13.7 ± 6.2
66
34

7075-T6

Tip
10.9 ± 3.5
55.8
44.2

Mid-section
12.3 ± 3.9
59.5
40.5

Root
12.8 ± 4.1
49.9
50.1

The as received extruded AZ31 base metal consists of bimodal grains, including elongated lamellar and equiaxed grains with a range of 265 to 2.5 m. EBSD analysis has been performed across a single gear tooth (FIG. 9 section (a)) and different sections of the tooth from the tip (b), mid-section (c), and root (d), as shown in FIG. 9 section 4(a). An inverse pole figure (JPF) map near the edge of the gear tooth confirms fine recrystallized grains (FIG. 9 section (a1)). IPF maps at three different regimes (FIG. 9 section (b1), (c1), and (d1)) exhibit bi-modal grains, equiaxed dynamic recrystallized grains (DRX), and some elongated lamellar grains as well. The average grain sizes (GS) in the tip, mid-section, and root are 12.4±9.4 μm, 12.6±9.8 m, and 13.7±6.2 μm, respectively (Table 1). The high-angle grain boundary (HAGB) and low-angle grain boundary (LAGB) fractions (Table 1) are comparable between the tip (FIG. 9 section (b2)) and mid-section (FIG. 9 section (c2)) regions of the tooth, the largest fraction of the HAGB is prominent in the root (FIG. 9 section (d2)) compared to the tip and mid-section. The SPH model-based analysis indicates that gradients in effective strain, strain rate, and temperature near the root are responsible for the variation in location specific GB type. At a single location however, the HAGB fraction is larger than the LAGB fraction, indicating the majority of grains within a given area having undergone fragmentation either during or prior to the FSF operation. A handful of studies mentioned through-thickness grain size variation and tried to correlate it with the evolution of high- and low-angle grain boundary fractions. The HAGB fraction has direct relevance to the plastic strain generated during the process.

These grain sizes and grain boundary fractions clearly indicate uniform deformation, temperature, and strain distribution away from core, which justifies the observation from the SPH models. As indicated by the SPH model, unlike the materials close to the core of the gear, the materials in the teeth region experiences less shear stresses and more compressive stress/strains. However, toward the tip of the teeth due to the interaction with the die-wall significant grain refinement is observed, which is due to the faster cooling rate toward the edges and greater frictional forces experienced during the deformation. The AZ31 base metal pole figure represents a typical basal fiber texture pattern for extrudate hexagonal close-packed metals. Observing the (0001) pole-figures in FIG. 10, textures present in the tip and mid-section of the tooth do not differ significantly from the basal texture. The texture patterns seen in the tip, mid-section, and root of the tooth do not widely differ from the base condition.

EBSD analysis has been performed across the ZY plane of the tooth root from one edge to mid-section as schematically represented with a red parallelogram in FIG. 11 section (a). The IPF map (FIG. 11 section (b)) of this section shows several interesting phenomena elongated grains in the mid-section, and prominent twin interactions near the edge. During the forging step, the materials are compressed downward and also flow radially to fill up the voids in the die. The downward direction (Z direction) of the grain elongation indicates the flow path during the forging step. Understanding this complex flow distribution in the tooth (along the thickness direction) is important to explaining deformation phenomena. The high-magnification IPF map and HAGB/LAGB in FIG. 11 sections (b1) and (b2) Indicate twinning is more prominent near the edge while the lamellar grains in the mid-section are likely due to constrained material flow as a result of die-wall interactions, the mid-section is free of this constraint. SPH-based models are in good agreement with these microstructural observations. The SPH model (FIG. 12 sections (a1)-(a3)) exhibits that for Mg alloy gear, a higher degree of temperature and strain rate accumulation near the crown and bottom of the tooth edges are less constrained than the midsection. Several studies have already reported twinning interaction during SPD of Mg in detail. Twins are indexed as (11-20) oriented by 86°, which is recognized as tension twinning (TTW). TTWs in Mg are common during SPD processes and are activated to accommodate straining during the process. High compressive force and strain rate during forging across the thickness direction are attributed to the formation of TTWs. The average GS near the edges is around 19.63 μm, whereas the center regime consists of lamellar grains of ˜110.2 μm. Twin-twin interaction would block the dislocation slips and result in high dislocation density and the resulting twin-induced grain refinement, which is very prominent in this case. Prior studies have reported similar observations. The refined grains may be helpful in increasing hardness and strength at the walls and bases of the teeth, where wear resistance is usually desirable.

3.2 AA 7075-T6 Gear Fabrication and Characterization

FIG. 13 sections (a), (b, b1), and (c, c1) show the SPH particle representation of equivalent plastic strain, strain rate, and temperature profiles, respectively, in the AA7075-T6 gear. The trends of effective strain (FIG. 13 section (a)), strain rate, and temperature distribution are similar to those of the previous magnesium gear. However, the amount of effective strain across the cross-section of the AA7075-T6 gear is higher compared to AZ31, with lowest value of 214% and highest value of 4632% (there is a wide range of variation due to considering several points including the gear tooth edges etc.). Compared to AZ31, the strain rate is more evenly distributed in AA7075-T6 gear with a maximum value of 5.309 s⁻¹and a minimum value of 4.254 s⁻¹. The temperature gradient is also lower compared to AZ31. The overall temperature in the gear center is around 480 to 520° C., indicating that dynamic recrystallization could happen during I-FSF. Higher temperature in this particular case is probably due to a few reasons: (a) AA7075 has higher flow stress than AZ31, which will release more heat energy to elevate the temperature when it is deforming and flowing, this in turn promotes a higher degree of plastic deformation of the billet material; (b) the tool's rotational speed during I-FSF of AA 7075-T6 is lower than AZ31 Mg to restrict abrupt increments of temperature during the process as AA7075-T6 is more sensitive to incipient melting. However, using temperature control algorithm during I-FSF, we can address this issue. The SPH particle X-Y (radial and tangential) displacement results depicted a similar pattern, indicating the direction of the material points deformation. Again, the material points at the gear teeth shank have less displacement (0.404 mm) from their original locations, while the material points in the gear teeth travel farther from their original locations (4.232 mm, 9.48× more), indicating the material movement toward the deformation direction. The highest displacement point is close to tool/billet contacting surface, with a maximum value of 13.485 mm (32.38× more).

The as received AA 7075-T6 base exhibits typical coarse and elongated grains similar to commercial extrudates. FIG. 14 section (a) represents the overall IPF-Z map and the corresponding grain distribution across the tooth, which includes the tip (marked as b), mid-plane (marked as c), and area away from core (marked as d). There is a striking difference between the base and forged microstructure. Uniform distribution of equiaxed and refined DRXs is observed in all the three regimes (FIG. 14 sections (b1), (c1), and (d1)). IPF maps in FIG. 14 sections (b1) and (c1) indicate that the grains are elongated toward the tip of the tooth, whereas grains are elongated in the radial direction in FIG. 14 section (d1). The HAGB and LAGB fractions are very close to each other irrespective of the three different regimes, indicating the presence of both partially and fully recrystallized grains in the tooth. Effective strain and temperature distribution maps from SPH particle distribution are in agreement with the EBSD results.

EBSD analysis was performed at the core of the gear across the rough thickness direction, as shown in the schematic and corresponding IPF map in FIG. 15 section (a). Grain orientation indicates a through-thickness flow pattern in the forging direction. Three different regions across the thickness are marked as b: close to the shoulder, c: mid-thickness, and d: bottom, as shown in FIG. 15 section (a). Grain size and distribution are distinctly different in region b compared to locations c and d. At Region b (FIG. 15 section (b1)) consists of fine, equiaxed DRX grains whereas region c (FIG. 15 section (c1)) and region d (FIG. 15 section (d1)) are composed of bi-modal lamellar pancake grains with some fine grains between the lamellae. The SPH-based model clearly reveals smaller temperature range was obtained by the Al alloy gear than the Mg alloy gear, primarily due to its larger thermal conductivity. Within the Al alloy gear, high temperature (FIG. 16 section (a1)), high strain (FIG. 16 section (a2)), and strain rate (Figure section (a3)) are accumulated in core of the gear as the material is being stirred with the pin feature, resulting in violent mixing and a high degree of plastic deformation that is unlike teeth. However, the top surface of the core is experiencing the maximum forge force from the shoulder, which is attributed to high temperature and strain accumulation resulting in a higher degree of DRX and grain refinement in region b.

Region b near the shoulder experiences higher plastic strain, creating a higher degree of grain refinement and resulting in a higher fraction of HAGB. The typical grain structure of sub-grains trapped in the lamella layer development is known as a “necklace”-type microstructure, which is generally observed when materials undergo a discontinuous dynamic recrystallization (DDRX) mechanism. This is more prominent in region c compared to d. During DDRX, new grains evolve with HAGBs due to dynamic nucleation and grain growth. The microstructure analysis results presented in this current study are very encouraging, as a higher degree of recrystallization/grain refinement promotes excellent strength, formability, and in some cases superplastic properties. The extent of DRX in our sample is not uniform due to the strain and temperature variation through thickness. However, the process parameters can be optimized for a more uniform strain and temperature profile.

3.3 5083-TiB₂MMC Gear from Powder Precursor

With the successful demonstration of the fabrication of a spur gear in a single step from less formable AZ31 Mg and 7075-T6 billet, we have explored the same approach with AA5083 and 10 vol % of titanium diboride alloy powder (TiB₂) as the starting materials. The alloy powder was first friction consolidated, followed by I-FSF to manufacture a 14-tooth MMC gear as shown in FIG. 17 section (a).

For any MMC structure, the distribution of the reinforcing particles in the matrix is the most important factor for determining the properties. Detailed SEM/energy dispersive X-ray spectroscopy (EDS) analysis has been performed at the gear teeth and near the core to see the distribution of TiB₂, as shown in FIG. 17 section (b) and marked as c and d for the high-magnification SEM analysis. Homogenous and uniform distribution of TiB₂is clearly seen across the matrix both near tip of the teeth (FIG. 13 section (c1)) and near the core (FIG. 17 section (c2)). High-magnification SEM image (inset of FIG. 17 sections (c1) and (d1)) presents grain boundaries decorated with TiB₂. Another notable difference is the grain orientation, elongation, and flow patterns of TiB₂between the core and the teeth. EDS elemental mapping for Al (FIG. 17 section (d1)) and Ti (FIG. 17 section (d2)) confirms the uniform distribution of TiB₂across the matrix. Microhardness mapping across the teeth and core exhibits an average microhardness of ˜102 HV, which is a ˜20% improvement compared to commercially available AA 5083 (O) (FIG. 17 section (e)). This observation reveals that using alloy powder as the starting material has the potential to enhance properties farther, especially for heat-treated aluminum alloys. These exciting results via the powder precursor route open up a window for MMC alloy development for gear and brake material via the I-FSF process with excellent strength, hardness, high fatigue, and wear performance.

While, we have successfully demonstrated gear manufacturing via I-FSF for high strength Al alloys, Mg alloys and MMC's, there are several challenges associated with tool material, tool design and process development for high-temperature material gear manufacturing. We are still exploring different routes and materials set to make this process productive and commercially viable in near future.

4. Conclusion

In this study, we have successfully demonstrated in-situ friction stir forging (I-FSF) to manufacture complex shape/near-net shape gears from solid billet or powder precursor of the low workability lightweight materials. This process has the potential to compete with the current processes for the gear manufacturing industries which demand tailored physical and mechanical properties for specific applications with some fine tuning. We have demonstrated or observed:

- Fabrication of a 14-tooth spur gear out of inherently poor formable AZ31 Mg, high-strength AA 7075-T6, and AA5083-10 vol % TiB₂composite in a single step via the I-FSF process.
- SPH simulations predicted strain rates of 4-5 s−1. When combined with the frictional heat provided by the rotating tool, the intense deformation resulted in local temperatures between 520 and 560° C., sufficient to plasticize the workpiece and fill the complex die shapes.
- Parallel to the strain and temperature predictions, EBSD analysis indicated the formation of recrystallized fine grains in the range of 6-13 μm near the core, teeth, and through-thickness direction for both AZ31 Mg and AA7075-T6. However, there was degree of variation in the refinement.
- For the MMC gears, the mixture of AA5083 and 10 vol % TiB₂powders was first friction consolidated and then forged into a 14-tooth gear. Uniform distribution of TiB₂in the aluminum matrix and decoration of the grain boundaries enhanced microhardness by ˜20% compared to the base 5083 (O) alloy.

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