Patent Application
20120103476
Aluminum alloys are useful in a variety of applications. However, improving one property of an aluminum alloy without degrading another property often proves elusive.
Broadly, the present patent application relates to new 5xxx aluminum alloy products having an improved combination of properties. 5xxx aluminum alloys are aluminum alloys having magnesium as the predominate alloying ingredient, other than aluminum, and containing silicon as an impurity. The new 5xxx aluminum alloy products are made from aluminum alloys containing 0.50 to 3.25 wt. % Mg, 0.05 to 0.20 wt. % Sc and/or 0.05 to 0.20 wt. % Zr, up to 0.50 wt. % in total of Cu and Ag, less than 0.10 wt. % Mn, up to 0.30 wt. % in total of Cr, V and Ti, up to 0.50 wt. % in total of Ni and Co, up to 0.25 wt. % Fe, up to 0.25 wt. % Si, up to 0.50 wt. % Zn, and up to 0.10 wt. % of any other element, with the total of these other elements not exceeding 0.35 wt. %, the balance being aluminum. The new 5xxx aluminum alloys may comprise, consist essentially of, or consist of the stated ingredients. The new 5xxx aluminum alloys may realize an improved combination of properties, such as an improved combination of two or more of electrical conductivity, strength, strength retention, and intragranular corrosion resistance, among others, as shown by the below examples. The new 5xxx aluminum alloys may be used in high strength electrical conductor products, among others.
The new 5xxx aluminum alloy products may realize high electrical conductivity. In one embodiment, a new 5xxx aluminum alloy product realizes an electrical conductivity of at least 35% IACS. In other embodiments, a new 5xxx aluminum alloy product realizes an electrical conductivity of at least 36%, or at least 37%, or at least 37.5%, or at least 38%, or at least 39%, or at least 40%, or at least 41%, or at least 42%, or at least 42.5%, or at least 43%, or at least 44%, or at least 45%, or at least 46%, or at least 47%, or at least 47.5%, or at least 48%, or at least 49%, or at least 50%, or at least 51%, or at least 52%, or at least 53%, or at least 54%, or at least 55% IACS, or higher. These properties are measured after the new 5xxx aluminum alloy product has been stabilized, i.e., annealed at 250° F. for 6 hours.
The new 5xxx aluminum alloy products may realize high strength. In one embodiment, a new 5xxx aluminum alloy product realizes a longitudinal (L) tensile yield strength (TYS) of at least 270 MPa. In other embodiments, a new 5xxx aluminum alloy product realizes a longitudinal tensile yield strength of at least 280 MPa, or at least 290 MPa, or at least 300 MPa, or at least 310 MPa, or at least 320 MPa, or at least 330 MPa, or at least 340 MPa, or at least 350 MPa, or at least 360 MPa, or at least 370 MPa, or at least 380 MPa, or at least 390 MPa, or at least 400 MPa, or higher. These properties are measured after the new 5xxx aluminum alloy has been stabilized, i.e., annealed at 250° F. for 6 hours.
The new 5xxx aluminum alloy products may realize high retained strength. For example, a thermally exposed version of the new 5xxx aluminum alloy product (e.g., exposed to temperatures of 250° F.-500° F., or higher, for 100 hours+/−0.5 hour) may retain at least 70% of its longitudinal tensile yield strength relative to the longitudinal tensile yield strength of a non-thermally exposed version of the same 5xxx aluminum alloy product. A non-thermally exposed version of the same 5xxx aluminum alloy product is the product as annealed at 250° F. for 6 hours (i.e., the stabilized baseline product). A piece of the non-thermally exposed version of the 5xxx aluminum alloy product is then exposed to elevated temperature for an additional 100 hours+/−0.5 hour to obtain the thermally exposed version of the new 5xxx aluminum alloy product. To determine strength retention, strength properties of both the non-thermally exposed and the thermally exposed products are measured at room temperature, and in accordance with ASTM E8 and B557. See, Example 4, below.
Strength retention may be measured relative to the longitudinal tensile yield strength, the long-transverse tensile yield strength and/or the short-transverse yield strength of the aluminum alloy. In one embodiment, strength retention is measured relative to longitudinal tensile yield strength. Those skilled in the art recognize that different combinations of temperatures and/or exposure periods may yield varying results.
In one approach, the thermally exposed version is exposed to a temperature of 260° F. for 100 hours+/−0.5 hour. In this approach, the thermally exposed version may realize a retained longitudinal tensile yield strength of at least 95% relative to the longitudinal tensile yield strength of a non-thermally exposed version of the same 5xxx aluminum alloy product. In one embodiment, the thermally exposed version may realize a retained strength of at least 96% relative to the non-thermally exposed version of the same 5xxx aluminum alloy product. In other embodiments, the thermally exposed version may realize a retained strength of at least 97%, such as at least 98%, or at least 99%, or at least 100% relative to the non-thermally exposed version of the same 5xxx aluminum alloy product. In some embodiments, the thermally exposed version of the new 5xxx aluminum alloy product has a higher strength than the non-thermally exposed version of the same 5xxx aluminum alloy product, such as at least about 1% or 2% higher strength, i.e., a retained strength of at least 101%, or at least 102%. See, Example 4, below.
In another approach, the thermally exposed version is exposed to a temperature of 300° F. for 100 hours+/−0.5 hour. In this approach, the thermally exposed version may realize a retained longitudinal tensile yield strength of at least 93% relative to the longitudinal tensile yield strength of a non-thermally exposed version of the same 5xxx aluminum alloy product. In one embodiment, the thermally exposed version may realize a retained strength of at least 94% relative to the non-thermally exposed version of the same 5xxx aluminum alloy product. In other embodiments, the thermally exposed version may realize a retained strength of at least 95%, such as at least 96%, or at least 97%, or at least 98% relative to the non-thermally exposed version of the same 5xxx aluminum alloy product.
In yet another approach, the thermally exposed version is exposed to a temperature of 350° F. for 100 hours+/−0.5 hour. In this approach, the thermally exposed version may realize a retained longitudinal tensile yield strength of at least 84% relative to the longitudinal tensile yield strength of a non-thermally exposed version of the same 5xxx aluminum alloy product. In one embodiment, the thermally exposed version may realize a retained strength of at least 85% relative to the non-thermally exposed version of the same 5xxx aluminum alloy product. In other embodiments, the thermally exposed version may realize a retained strength of at least 86%, such as at least 87%, or at least 88%, or at least 89%, or at least 90%, or at least 91% relative to the non-thermally exposed version of the same 5xxx aluminum alloy product.
In yet another approach, the thermally exposed version is exposed to a temperature of 400° F. for 100 hours+/−0.5 hour. In this approach, the thermally exposed version may realize a retained longitudinal tensile yield strength of at least 75% relative to the longitudinal tensile yield strength of a non-thermally exposed version of the same 5xxx aluminum alloy product. In one embodiment, the thermally exposed version may realize a retained strength of at least 80% relative to the non-thermally exposed version of the same 5xxx aluminum alloy product. In other embodiments, the thermally exposed version may realize a retained strength of at least 82%, such as at least 84%, or at least 86%, or at least 88% relative to the non-thermally exposed version of the same 5xxx aluminum alloy product.
In yet another approach, the thermally exposed version is exposed to a temperature of 450° F. for 100 hours+/−0.5 hour. In this approach, the thermally exposed version may realize a retained longitudinal tensile yield strength of at least 70% relative to the longitudinal tensile yield strength of a non-thermally exposed version of the same 5xxx aluminum alloy product. In one embodiment, the thermally exposed version may realize a retained strength of at least 75% relative to the non-thermally exposed version of the same 5xxx aluminum alloy product. In other embodiments, the thermally exposed version may realize a retained strength of at least 80%, such as at least 82%, or at least 84%, or at least 86% relative to the non-thermally exposed version of the same 5xxx aluminum alloy product.
In yet another approach, the thermally exposed version is exposed to a temperature of 500° F. for 100 hours+/−0.5 hour. In this approach, the thermally exposed version may realize a retained longitudinal tensile yield strength of at least 70% relative to the longitudinal tensile yield strength of a non-thermally exposed version of the same 5xxx aluminum alloy product. In one embodiment, the thermally exposed version may realize a retained strength of at least 75% relative to the non-thermally exposed version of the same 5xxx aluminum alloy product. In other embodiments, the thermally exposed version may realize a retained strength of at least 80%, such as at least 82%, or at least 84%, or at least 85% relative to the non-thermally exposed version of the same 5xxx aluminum alloy product.
The new 5xxx aluminum alloy products may realize low intragranular corrosion. In one embodiment, a new 5xxx aluminum alloy product realizes a mass loss of not greater than 15 mg/cm2 when tested in accordance with ASTM G67. To test corrosion resistance, the new 5xxx aluminum alloy product is annealed at 250° F. for 6 hours, and is then sensitized by exposing to a temperature of 100° C. (212° F.) for 1 week. See, Example 1, below. In other embodiments, a new 5xxx aluminum alloy product realizes a mass loss of not greater than 14 mg/cm2, or not greater than 13 mg/cm2, or not greater than 12 mg/cm2, or not greater than 11 mg/cm2, or not greater than 10 mg/cm2, or not greater than 9 mg/cm2, or not greater than 8 mg/cm2, or not greater than 7 mg/cm2, or not greater than 6 mg/cm2, or not greater than 5 mg/cm2, or less mass loss.
The new 5xxx aluminum alloys generally include from 0.5 wt. % to 3.25 wt. % Mg. In one embodiment, the new 5xxx aluminum alloys include at least 0.80 wt. % Mg. In one embodiment, the new 5xxx aluminum alloys include not greater than 2.90 wt. % Mg. The amount of magnesium used in the alloy may be related to the strength, electrical conductivity, and/or corrosion resistance properties of the alloy. High electrical conductivity and better corrosion resistance occurs with lower levels of magnesium. Higher strength occurs with higher levels of magnesium. See Tables I-A to I-C, below, for various magnesium ranges relative to various electrical conductivity properties.
The new 5xxx aluminum alloys may include both scandium (Sc) and zirconium (Zr), and generally from 0.05 to 0.20 wt. % each of Sc and Zr. The combination of scandium and zirconium may contribute to increased strength. In one embodiment, the new 5xxx aluminum alloys include from 0.07 to 0.18 wt. % each of Sc and Zr. However, in other embodiments, only one of scandium or zirconium may be used, and in the above amounts, such as in lower strength applications.
The new 5xxx aluminum alloys may optionally include copper (Cu) and/or silver (Ag). Copper and/or silver may improve strength. However, too much copper may decrease corrosion resistance. In one approach, the new 5xxx aluminum alloys include up to 0.50 wt. % Cu, and silver is absent from the alloy (i.e., the alloy contains silver as an “other element”, defined below). In one embodiment of this approach, the new 5xxx aluminum alloys include 0.05 to 0.50 wt. % Cu. In another embodiment of this approach, the new 5xxx aluminum alloys include 0.10 to 0.45 wt. % Cu. In yet another embodiment of this approach, the new 5xxx aluminum alloys include 0.20 to 0.40 wt. % Cu. In yet another embodiment of this approach, the new 5xxx aluminum alloys include 0.25 to 0.35 wt. % Cu.
In another approach, the new 5xxx aluminum alloys include up to 0.50 wt. % Ag, and copper is absent from the alloy (i.e., the alloy contains copper as an “other element”, defined below). In one embodiment of this approach, the new 5xxx aluminum alloys include 0.05 to 0.50 wt. % Ag. In another embodiment of this approach, the new 5xxx aluminum alloys include 0.10 to 0.45 wt. % Ag. In yet another embodiment of this approach, the new 5xxx aluminum alloys include 0.20 to 0.40 wt. % Ag. In yet another embodiment of this approach, the new 5xxx aluminum alloys include 0.25 to 0.35 wt. % Ag.
In yet another approach, the new 5xxx aluminum alloys include both Cu+Ag and up to 0.50 wt. % Ag. In one embodiment of this approach, the new 5xxx aluminum alloys include 0.05 to 0.50 wt. % total of Cu+Ag. In another embodiment of this approach, the new 5xxx aluminum alloys include 0.10 to 0.45 wt. % total of Cu+Ag. In yet another embodiment of this approach, the new 5xxx aluminum alloys include 0.20 to 0.40 wt. % total of Cu+Ag. In yet another embodiment of this approach, the new 5xxx aluminum alloys include 0.25 to 0.35 wt. % total of Cu+Ag.
The new 5xxx aluminum alloys should include low amounts of manganese (Mn). Manganese detrimentally impacts electrical conductivity. In one embodiment, the new 5xxx aluminum alloys include less than 0.10 wt. % Mn. In another embodiment, the new 5xxx aluminum alloys include not greater than 0.07 wt. % Mn. In yet another embodiment, the new 5xxx aluminum alloys include not greater than 0.05 wt. % Mn. In yet another embodiment, the new 5xxx aluminum alloys include not greater than 0.03 wt. % Mn. In yet another embodiment, the new 5xxx aluminum alloys include not greater than 0.01 wt. % Mn.
The new 5xxx aluminum alloys should restrict the amount of chromium (Cr), vanadium (V), and titanium (Ti). These elements may detrimentally impact electrical conductivity. In one embodiment, the new 5xxx aluminum alloys include not greater than 0.30 wt. % total of Cr, V and Ti (i.e., the total combined amounts of Cr, V, and Ti does not exceed 0.30 wt. %). In one embodiment, the new 5xxx aluminum alloys include not greater than 0.25 wt. % total of Cr, V and Ti. In yet another embodiment, the new 5xxx aluminum alloys include not greater than 0.20 wt. % total of Cr, V and Ti. In yet another embodiment, the new 5xxx aluminum alloys include not greater than 0.15 wt. % total of Cr, V and Ti. In yet another embodiment, the new 5xxx aluminum alloys include not greater than 0.10 wt. % total of Cr, V and Ti. In yet another embodiment, the new 5xxx aluminum alloys include not greater than 0.05 wt. % total of Cr, V and Ti. In yet another embodiment, the new 5xxx aluminum alloys include not greater than 0.03 wt. % total of Cr, V and Ti. In any of these embodiments, the new 5xxx aluminum alloy may include at least 0.005 wt. % Ti (e.g., for grain refining purposes).
The new 5xxx aluminum alloys should restrict the amount of nickel (Ni) and cobalt (Co). These elements may detrimentally impact electrical conductivity. In one embodiment, the new 5xxx aluminum alloys include not greater than 0.50 wt. % total of Ni and Co (i.e., the total combined amounts of Ni and Co does not exceed 0.50 wt. %). In one embodiment, the new 5xxx aluminum alloys include not greater than 0.35 wt. % total of Ni and Co. In another embodiment, the new 5xxx aluminum alloys include not greater than 0.20 wt. % total of Ni and Co. In yet another embodiment, the new 5xxx aluminum alloys include not greater than 0.15 wt. % total of Ni and Co. In yet another embodiment, the new 5xxx aluminum alloys include not greater than 0.10 wt. % total of Ni and Co. In yet another embodiment, the new 5xxx aluminum alloys include not greater than 0.05 wt. % total of Ni and Co. In yet another embodiment, the new 5xxx aluminum alloys include not greater than 0.03 wt. % total of Ni and Co. In yet another embodiment, the new 5xxx aluminum alloys include not greater than 0.01 wt. % total of Ni and Co.
The new 5xxx aluminum alloys should restrict the amount of iron (Fe), silicon (Si) and zinc (Zn) impurities. Iron and silicon impurities may detrimentally impact strength. In one embodiment, the new 5xxx aluminum alloys include not greater than 0.25 wt. % each of Fe and Si. In another embodiment, the new 5xxx aluminum alloys include not greater than 0.20 wt. % Fe and not greater than 0.15 wt. % Si. In yet another embodiment, the new 5xxx aluminum alloys include not greater than 0.15 wt. % Fe and not greater than 0.10 wt. % Si. In yet another embodiment, the new 5xxx aluminum alloys include not greater than 0.10 wt. % Fe and not greater than 0.05 wt. % Si. Zinc impurities may detrimentally affect corrosion resistance. In one embodiment, the new 5xxx aluminum alloys include not greater than 0.50 wt. % Zn. In another embodiment, the new 5xxx aluminum alloys include not greater than 0.35 wt. % Zn. In yet another embodiment, the new 5xxx aluminum alloys include not greater than 0.25 wt. % Zn.
The new 5xxx aluminum alloys may be substantially free of other elements (e.g., casting aids and other impurities, i.e., other than the iron, silicon and zinc impurities described above). As used herein, “other elements” means any other elements of the periodic table other than the above-listed magnesium, scandium, zirconium, copper and/or silver (as applicable—see above), manganese, chromium, vanadium, titanium, nickel, cobalt, iron, silicon, and zinc, described above. In the context of this paragraph the phrase “substantially free” means that the new 5xxx aluminum alloys contain not more than 0.10 wt. % each of any other element, with the total combined amount of these other elements not exceeding 0.35 wt. % in the new 5xxx aluminum alloy. In another embodiment, each one of these other elements, individually, does not exceed 0.05 wt. % in the 5xxx aluminum alloy, and the total combined amount of these other elements does not exceed 0.15 wt. % in the 5xxx aluminum alloy. In another embodiment, each one of these other elements, individually, does not exceed 0.03 wt. % in the 5xxx aluminum alloy, and the total combined amount of these other elements does not exceed 0.10 wt. % in the 5xxx aluminum alloy.
Examples of various types of new 5xxx aluminum alloy compositions are provided in Tables I-A to I-C, below. Embodiments of properties that may be achieved by the new 5xxx aluminum alloys when rolled to a thickness of about 1.0-1.1 mm, and annealed at a temperature of 250° F. for a period of 6 hours are provided in Table I-D, below.
Any of the above-described examples and embodiments are within the scope of the claimed invention, and may be utilized in any claim to define the invention.
Generally, the new 5xxx aluminum alloys are in the form of a wrought product. For purposes of the present patent application, wrought products include products made from semi-continuous casting processes, such as ingot or billet casting processes, as well as those products made from continuous casting processes, such as belt casting, rod casting, twin roll casting, twin belt casting (e.g., Hazelett casting), drag casting, and block casting, among others. The wrought products may be, for example, a sheet, extrusion, forging, rod or wire, and pipe or tube, among others. A sheet is a rolled product having a thickness of 0.006 to 0.249 inch (0.1524 to 6.3246 mm). An extrusion is product formed by pushing material through a die. A forging is metal part worked to a predetermined shape by one or more processes such as hammering, pressing or rolling. In one embodiment, the forging is a die forging. A die forging is a forging formed to the required shape and size by working impression dies. A rod is a solid product that is long in relation to cross section, and which is 0.375 inch (9.525 mm) or greater in diameter. A wire is a solid wrought product that is long in relation to its cross section, which is square or rectangular with sharp or rounded corners or edges, or is round, a regular hexagon or regular octagon, and whose diameter or greatest perpendicular distance between parallel faces (except for flattened wire) is less than 0.375 inch (9.525 mm). A tube is a hollow wrought product that is long in relation to its cross section, which is round, a regular hexagon, a regular octagon, elliptical, or square or rectangular, with sharp or rounded corners, and that has a uniform wall thickness except as affected by corner radii. A pipe is a tube in standardized combinations of outside diameter and wall thickness, commonly designated by “Nominal Pipe Sizes” and “ANSI Schedule Numbers.” In one embodiment, the new 5xxx aluminum alloy product is in the form of sheet. In another embodiment, the new 5xxx aluminum alloy product is in the form of an extrusion. In another embodiment, the new 5xxx aluminum alloy product is in the form of a forging. In another embodiment, the new 5xxx aluminum alloy product is in the form of a die forging. In another embodiment, the new 5xxx aluminum alloy product is in the form of a wire. In another embodiment, the new 5xxx aluminum alloy product is in the form of a rod. In another embodiment, the new 5xxx aluminum alloy product is in the form of a tube. In yet another embodiment, the new 5xxx aluminum alloy product is in the form of a pipe.
To produce a new 5xxx aluminum alloy wrought product using a semi-continuous casting process, the new 5xxx aluminum alloy may be cast in the form of an ingot or billet, after which the ingot or billet is homogenized and hot worked to an intermediate gauge product. The intermediate gauge product may then be optionally thermally treated (e.g., annealed) and then cold worked to final gauge or form. After cold working, the product may be annealed for a time and temperature sufficient to stabilize properties (e.g., 6 hours at 250° F., or similar type of anneal). Similar steps may be employed with a continuous casting process, although hot working may not be required. In one embodiment, the new 5xxx aluminum alloy products are cold worked at least 10%. In other embodiments, the new 5xxx aluminum alloy products are cold worked at least worked at least 25%, or at least 50%, or at least 60%, or at least 70%, or at least 80%, or at least 90%, or more. In this regard, the new 5xxx aluminum alloy products may be processed to an H temper, such as any of an H1, H2 or H3 temper.
An H1 temper means that the alloy is strain hardened. An H2 temper means that the alloy is strain-hardened and partially annealed. An H3 temper means that the alloy is strain hardened and stabilized (e.g., via low temperature heating). In some embodiments, the new 5xxx aluminum alloy products may achieve an improved combination of properties in one or more of an H1X, H2X or an H3X temper, where X is a whole number from 1-9. This second digit following the designations H1, H2, H3 indicate the final degree of strain hardening. The number 8 is assigned to tempers having a final degree of strain-hardening equivalent to that resulting from approximately 75% reduction in area. Tempers between that of the 0 Temper (annealed) and 8 (full hard) are designated by the numbers 1 through 7. A number 4 designation is considered half-hard; number 2 is considered quarter-hard; and the number 6 is three-quarter hard. When the number is odd, the limits of ultimate strength are about halfway between those of the even numbered tempers. An H9 temper has a minimum ultimate tensile strength that exceeds the ultimate tensile strength of the H8 temper by at least 2 ksi.
Given the strength, electrical conductivity, corrosion resistance and/or strength retention properties of the new 5xxx aluminum alloy products, such products are well-suited as electrical conductors. An electrical conductor is a material whose primary application is to conduct electricity and that has an electrical conductivity of at least 35% IACS, such as any of the IACS values described above. Examples of electrical conductors include electrical connectors and electrical conveyors, among others. For the present patent application, the term “electrical conductors” does not include memory disk stock and the like, whose primary application is as a substrate for memory storage.
A high strength electrical conductor is an electrical conductor having a tensile yield strength of at least 270 MPa, such as any of the strength values described above.
A corrosion-resistant electrical conductor is an electrical conductor that realizes a mass loss of not greater than 15 mg/cm2 when tested in accordance with ASTM G67, such as any of the mass loss values described above.
A high strength retention electrical conductor is an electrical conductor that retains at least 70% of its longitudinal tensile yield strength after prolonged exposure to elevated temperature, relative to the longitudinal tensile yield strength of a non-thermally exposed version of the same 5xxx aluminum alloy product, as described above, and such as any of the strength retention values described above. In these embodiments, the mechanical properties may be measured at about room temperature (e.g., about 25° C.), such as after the thermal exposure has been completed.
An electrical connector is a device configured to reliably connect one thing to and another thing such that the two things are in sound electrical communication upon and during application of an electrical current. Non-limiting examples of electrical connectors include terminal blocks, pins, crimp-on connectors, plug and socket connectors, blade connectors, and ring and spade terminals, to name a few. In one embodiment, a first electrical connector is a male connector and a second electrical connector is a female connector, adapted to receive the male connector. In some of these embodiment, the male and female electrical connectors may be in a keyed arrangement, where the male connector may connect with the female connector only when the male connector is in a predetermined configuration and/or orientation relative to the female connector. In one embodiment, the male and female connectors may be reliably and/or repeatably connected to and disconnected from one another (i.e., mated and unmated), and over many connect and disconnect cycles. Examples of some useful electrical connectors using the aluminum alloy of the present application include automotive electrical connectors.
An automotive electrical connector is an electrical connector that is used in an automotive vehicle. One non-limiting example of an automotive electrical connector is an electrical distribution system. The automotive electrical connectors may include the aluminum alloys described herein, and those aluminum alloys may be corrosion resistant and/or have high strength retention, to name a few. Automotive electrical conductors may also and/or alternatively be in the form of an electrical conveyor, described below.
For purpose of the present application, an automotive vehicle means a vehicle designed to transport one or more passengers via locomotion using one or more motors and/or one or more engines. Non-limiting examples of automotive vehicles include hydrocarbon powered vehicles (e.g., gasoline, diesel, alcohol (e.g., ethanol), and mixtures thereof (e.g., E85), to name a few), electrically powered vehicles, and hybrid powered (hydrocarbon+electric) vehicles, among others. For example, buses, trains, cars, trucks, motorcycles, off-road vehicles, and airplanes, among others, are all automotive vehicles. Automotive vehicles may travel via rail, road, water, snow, earth, air and/or otherwise.
An electrical conveyor is a device whose primary application is to convey electricity from one point to another point. Examples of electrical conveyers include wires, cables and bus bars, among others. An electrical wire is an elongated piece, resembling a string, and which is designed to carry electrical current from a first location to a second location. A cable is a device including a plurality of electrical wires, generally in a twisted configuration. A bus bar is a device, usually in the form of a bar, which is designed to carry electrical current from a first location to a second location. A bus bar may be comprised of a plurality of long and/or thin sheets.
The electrical conductors may be in a plated or unplated form. When in plated form, the electrical conductors may include the new 5xxx aluminum alloy products with a plated portion included on one or more surfaces of the new 5xxx aluminum alloy products. The plated portion may include another metal, such as tin, zinc or copper, to name a few. The plated portion may be coupled to the new 5xxx aluminum alloy products via any suitable technique, such via electroplating and/or other known deposition techniques.
These and other aspects, advantages, and novel features of this new technology are set forth in part in the description that follows, and will become apparent to those skilled in the art upon examination of the description and figures, or may be learned by practicing one or more embodiments of the technology provided for by the patent application.
a is a graph illustrating electrical conductivity versus yield strength for various Example 3 alloys.
b is a graph illustrating electrical conductivity versus yield strength for various Example 3 alloys.
c is a graph illustrating electrical conductivity versus yield strength for various Example 3 alloys, with embodiments of performance trend lines illustrated for various alloys.
a is a graph illustrating thermal treatment temperature versus yield strength for various Example 2 and Example 3 alloys.
b is a graph illustrating electrical conductivity versus yield strength for various Example 2 and Example 3 alloys.
a is a graph illustrating yield strength versus cold work amount for various Example 5 alloys.
b is a graph illustrating electrical conductivity versus cold work amount for various Example 5 alloys.
a is a graph illustrating thermal treatment temperature versus yield strength for various Example 5 alloys.
b is a graph illustrating thermal treatment temperature versus yield strength for various Example 5 alloys.
a is a graph illustrating electrical conductivity versus yield strength for various Example 6 alloys.
b is a graph illustrating electrical conductivity versus yield strength for various Example 6 alloys.
c is a graph illustrating mass loss versus yield strength for various Example 6 alloys.
d is a graph illustrating electrical conductivity versus yield strength for various Example 6 alloys.
Various 5xxx aluminum alloys are cast as book molds. The experimental alloys have the composition provided in Table 1, below.
Unless otherwise indicated, other than the above-listed ingredients, all of the experimental alloys 1-14 contained about 0.01-0.02 wt. % Ti, not greater than 0.01 wt. % Cu, not greater than 0.04 wt. % Si as an impurity, not greater than 0.10 wt. % Fe as an impurity, not greater than 0.02 wt. % Zn as an impurity, not greater than 0.05 wt. % each of any other elements, and with the other elements not exceeding 0.15 wt. % in total, the balance being aluminum. Alloy 13 contained 0.94 wt. % Zn. Alloy 1 is similar to Alloy B of U.S. Pat. No. 5,624,632, to Baumann et al.
After casting, all of the samples are homogenized (preheated) using the following practice:
Linear ramp to 260° C. (500° F.) in 4 hrs
Soak at 260° C. (500° F.)+/−2° C. (5° F.) for 5 hrs
Linear ramp to 290° C. (550° F.) in 2 hrs
Soak at 290° C. (550° F.)+/−2° C. (5° F.) for 5 hrs
Linear ramp to 455° C. (850° F.) in 5 hrs
Soak at 455° C. (850° F.)+/−2° C. (5° F.) for 4 hrs
Air cool
After homogenization, the book molds are processed to an H3y type temper (e.g., an H38 temper). Specifically, the book molds are scalped to remove about 3 mm (about 0.125″) from both rolling faces; the sides of the book molds are also surface machined. Prior to hot rolling, all the book molds are given a heat-to-roll practice of from about 425 to about 455° C. (about 800 to 850° F.) for from about 30 to about 60 minutes, after which they are hot rolled. The book molds are hot rolled using a six pass schedule to a final gauge of about 7.1 mm (about 0.28 inch). A final hot roll exit temperature of about 260° C. (about 500° F.) is targeted. The pieces are air cooled, and then machined on the edges to minimize edge cracking. The material is then cold rolled about 80 to 85% to a nominal thickness of about 1 to 1.1 mm.
Each of the experimental alloys is divided into various pieces. Some of the pieces are subjected to a thermal treatment in the form of an anneal. Other pieces are not annealed. Table 2 correlates the thermal treatments (or lack thereof) to the various alloys pieces.
Each of the pieces is further split, and some of those splits are treated (sensitized), while others are not. The specific practice key is provided below, for correlating the mechanical properties of Table 3, below, to the sensitization category.
A=No thermal treatment (F temper)
B=1 week at 100° C. (212° F.)—Typical sensitization practice
C=1000 hrs at 85° C. (185° F.)—Alternative 1 sensitization practice
D=100 hrs at 125° C. (258° F.)—Alternative 2 sensitization practice
Material properties, including strength, ductility and corrosion resistance are measured for each piece, the results of which are provided in Table 3, below. Tensile properties are measured in the longitudinal direction in accordance with ASTM E8 and B557 using a sub-size specimen (about 100 mm). Duplicate tensile specimens are used for each condition. Corrosion properties are measured using the NAMLT (Nitric Acid Mass Loss Test) or “mass loss” test (ASTM G67-04) to assess intergranular corrosion resistance. Duplicate mass loss tests are run for each condition and the results are averaged. The material is tested in both the as-received (thermal treatment A) and thermally treated conditions (B, C and D). Thermal treatment can affect corrosion performance by accelerating the precipitation of the β phase (Mg5Al8), which can give an indication of potential long-term service behavior.
As shown in Table 3 and
Based on the Example 1 data, additional book mold testing is conducted on low Mg, no Mn 5xxx aluminum alloys. Nineteen additional experimental book molds are produced using generally the same practice described in Example 1. Two additional alloys (B-1 and B-2) having a composition similar to Alloy B of U.S. Pat. No. 5,624,623 to Baumann et al. are also produced in book mold form. The experimental materials and the Baumann materials are cold rolled about 80 to 85% to a nominal thickness of about 1 to 1.1 mm. Aluminum Association alloys 5454, 5086, 5052 are produced in book mold form, and processed to a final gauge of about 1 to 1.1 mm with 80 to 85% cold work using conventional 5xxx production practices.
The Example 2 alloy compositions are provided in Table 4, below. The thermal treatment chart is provided as Table 5, below. The mechanical and corrosion data are provided in Table 6, below. Only some of the alloys are tested for corrosion resistance.
Unless otherwise indicated below, other than the above-listed ingredients, all of the experimental alloys 15-33 and alloys AA5454, AA5086, AA5052, B-1 and B-2 contained about 0.01-0.02 wt. % Ti, not greater than 0.01 wt. % Cu, not greater than 0.06 wt. % Si as an impurity, not greater than 0.10 wt. % Fe as an impurity, not greater than 0.02 wt. % Zn as an impurity, not greater than 0.05 wt. % each of other elements, and with the other elements not exceeding 0.15 wt. % in total, the balance being aluminum. The prior art Aluminum Association alloys 5454, 5086, and 5052 contain not more than 0.13 wt. % Si and not more than 0.25 wt. % Fe. Alloy 5454 also contains 0.089 wt. % Cr and 0.11 wt. % Zn. Alloy 5086 contains 0.083 wt. % Cr. Alloy 5052 contains 0.2 wt. % Cr.
As shown in
With respect to pitting and exfoliation resistance, several 2 wt. % Mg alloys, with and without Cu, are subjected to corrosion resistance testing in accordance with a modified version of ASTM B117. The alloys are tested in the annealed condition and after sensitization treatments B or C are applied. The samples are alternatively immersed (AI) in a 3.5% NaCl solution (without stress), with 8 hours spray and 16 hours soak. The AI test is run for exposure intervals of 6, 10, 20 and 40 days. All alloys performed well, with no evidence of any corrosion attack.
Based on the Example 2 data, additional book mold testing is conducted on low Mg, no Mn 5xxx aluminum alloys, with Sc+Zr, and sometimes with Cu. Fifteen additional experimental book molds are produced using generally the same practice described in Example 1. The compositions of the additional book molds are provided in Table 7, below. Pieces of the Example 3 alloys received no thermal treatment (piece “a”) or were annealed at 250° F. for 6 hours (piece “b”). The mechanical and corrosion data are provided in Table 8, below.
Unless otherwise indicated below, other than the above-listed ingredients, all of the experimental alloys 34-48 contained about 0.01 wt. % Ti, not greater than 0.05 wt. % Si as an impurity, not greater than 0.17 wt. % Fe as an impurity, not greater than 0.01 wt. % Zn as an impurity, not greater than 0.05 wt. % each of other elements, and with the other elements not exceeding 0.15 wt. % in total, the balance being aluminum.
As shown in
a-15c illustrate the electrical conductivity versus yield strength performance of various Example 3 alloys. As shown in
c illustrates one manner of characterizing the new 5xxx aluminum alloy products. The new 5xxx aluminum alloy products are bounded by a minimum yield strength (L) of 270 MPa and a minimum electrical conductivity of 35% IACS, as shown by the solid lines. These properties are measured after the aluminum alloy is annealed at 250° F. for 6 hours. In this graph, a trend line of having an equation of EC=−0.195 (TYS)+Intercept is shown, where the intercept shifts based on the amount of Sc, Zr and/or Cu in the alloy. A minimum performance line is shown, having an equation of EC=−0.195 (TYS)+96. This minimum performance line correlates to the performance of the low Sc+Zr and no Cu alloys. As the amount of Sc+Zr and/or copper present in the new 5xxx aluminum alloys increases, the performance line shifts to the right by changing the intercept, but keeping the same slope (−0.195). For all Sc+Zr alloys with 0.2 wt. % Cu, the intercept is about 102-108 (an intercept of 105.4 is illustrated). For the 0.36 wt. % Cu alloys having lower levels of Sc+Zr, the intercept is about 107-109. For the 0.36 wt. % Cu alloys having higher levels of Sc+Zr, the intercept is about 109-111.
The performance trend correlates to the alloy performance of the Example 2 alloys that were also annealed at 250° F. for 6 hours. For instance, Alloys 19 and 26, which are no copper, low Sc+Zr alloys (0.156 and 0.138 wt. % Sc+Zr, respectively), generally meet the requirements set forth above for the Type B and D alloys. Of these alloys, one of the 0.138 wt. % Sc+Zr alloys barely misses the criteria of
Alloy 29, which contains no copper and higher levels of Sc+Zr alloy (0.27 wt. % Sc+Zr), falls within the bounds of the performance requirements of
Alloy 30, with no Sc+Zr, but 0.15 wt. % Cu, falls within the performance bounds of
Alloy 31, with lower levels of Sc+Zr (0.137), and 0.16 wt. % Cu, falls within the performance bounds of
Alloy 32, with lower levels of Sc+Zr (0.132), and 0.24 wt. % Cu, falls within the performance bounds of
Alloy 33, with lower levels of Sc+Zr (0.137), and 0.50 wt. % Cu, falls within the performance bounds of
Table 9, below, correlates the Cu and Sc+Zr levels to the intercept of the performance line in accordance with the data (sorted by increasing Cu level, which appears to have the most prominent affect on the shift of the intercept).
Based on these trends, it is expected that the new 5xxx aluminum alloys having high amounts of Cu and Sc+Zr could have a performance line intercept of 113, or higher.
The new 5xxx aluminum alloys generally have good corrosion resistance when Mg levels are kept below 3.25 wt. %, such as below 3.0 wt. %. As shown in
Salt spray tests similar to those described in Example 2 are conducted on a selection of the Example 3 alloys containing from about 2 wt. % to about 3 wt. % Mg, all of which also contain copper. The test samples are visually observed after 6, 10, 20, 40, and 80 days (20 days is the specification requirement). After 20 days of exposure, the samples do not show any evidence of attack for any of the thermal treatment conditions, although the higher copper alloys appear slightly darker in color. Even after 40 and 80 days exposure there is little or no attack.
Several Example 2 and Example 3 alloys are exposed to varying elevated temperatures for 100 hours, after which their electrical conductivity and mechanical properties are tested. The results of these tests are provided in Table 10, below. All tested alloys were those alloys that had been previously annealed at 250° F. for 6 hours.
As illustrated in
Hot rolled, but non-cold rolled portions of alloys 38, 43, and 48, from above, are cold rolled 30%, 50%, 65% and 83%. The alloys received no thermal treatment (piece “a”) or were annealed at 250° F. for 6 hours (piece “b”). The mechanical data are provided in Table 11, below.
As shown in
The alloys are also tested for strength retention by prolonged exposure to elevated temperature as shown in Table 12 below. As shown in
Additional book mold testing is conducted on low Mg, no Mn 5xxx aluminum alloys, with Sc+Zr, and sometimes with Cu. Fourteen additional experimental book molds are produced using generally the same practice described in Example 1. The compositions of the additional book molds are provided in Table 13, below. Pieces of the Example 6 alloys received no thermal treatment (piece “a”) or were annealed at 250° F. for 6 hours (piece “b”). The mechanical and corrosion data are provided in Table 14, below.
Unless otherwise indicated, other than the above-listed ingredients, all of the experimental alloys 49-63 contained about 0.01 wt. % Ti, not greater than 0.05 wt. % Si as an impurity, not greater than 0.10 wt. % Fe as an impurity, not greater than 0.01 wt. % Zn as an impurity, the balance being aluminum and other elements, the combined amount of other elements not exceeding 0.05 wt. % each, and not more than 0.15 wt. % in total.
As shown in
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While various embodiments of the new technology described herein have been described in detail, it is apparent that modifications and adaptations of those embodiments will occur to those skilled in the art. However, it is to be expressly understood that such modifications and adaptations are within the spirit and scope of the presently disclosed technology.
| Number | Date | Country | Kind |
|---|---|---|---|
| PCT/US2011/058293 | Oct 2011 | US | national |
This patent application claims priority to U.S. Provisional Patent Application No. 61/408,269, entitled “IMPROVED 5XXX ALUMINUM ALLOYS, AND METHODS FOR PRODUCING THE SAME”, filed Oct. 31, 2010, and U.S. Provisional Patent Application No. 61/435,543, entitled “IMPROVED 5XXX ALUMINUM ALLOYS, AND METHODS FOR PRODUCING THE SAME”, filed Jan. 24, 2011. This patent application also claims priority to PCT Patent Application No. PCT/US11/58293, entitled “IMPROVED 5XXX ALUMINUM ALLOYS, AND METHODS FOR PRODUCING THE SAME”, filed Oct. 28, 2011. Each of the above-identified patent applications is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 61408269 | Oct 2010 | US | |
| 61435543 | Jan 2011 | US |
