This disclosure relates to articles having a thermally-controlled microstructure and to methods of manufacture thereof. In particular, this disclosure relates to articles having a thermally-controlled microstructure that is manufactured by additive manufacturing.
Disclosed herein is a flow control device comprising a conduit; and jaws lining an inner surface of the conduit; where the jaws comprise a plurality of structural units, wherein each structural unit comprises a first portion; a second portion; wherein the second portion contacts the first portion; and a third portion; wherein the third portion is in communication with the first portion and the second portion and has a lower stiffness than the first portion and the second portion; where the first portion has a first value of a property and where the second portion has a second value of the same property, such that the first value acts as a restraining or enhancing force on the second value; wherein the first portion comprises a first metal and wherein the second portion comprises a second metal that is different from the first metal; wherein the jaws are operative to vary a cross-sectional area of fluid flow in the conduit.
In an embodiment, the plurality of structural units form a repeat unit and wherein the jaws are encompassed in a polymer.
In another embodiment, the repeat unit repeats itself throughout a volume of an article.
In yet another embodiment, the plurality of structural units are periodically spaced.
In yet another embodiment, the first portion and the second portion each have domain sizes ranging from 10 micrometers to 20 millimeters and are placed in position using additive manufacturing.
In yet another embodiment, the first portion and the second portion both comprise a single shape memory alloy.
In yet another embodiment, the first preset state acts as a restraint on the first preset state.
Disclosed herein is a flow control device comprising a planar or curved surface having a base surface; a plurality of sections that comprise a first portion; a second portion; wherein the second portion contacts the first portion; and a third portion; wherein the third portion is in communication with the first portion and the second portion and is more compressible than the first portion and the second portion; where the first portion has a first value of a property and where the second portion has a second value of the same property, such that the first value acts as a restraining or enhancing force on the second value; wherein the first portion comprises a first metal and wherein the second portion comprises a second metal that is different from the first metal; where the plurality of sections are operative to undergo a change in height from a base surface.
In an embodiment, the planar or curved surface can change from hydrophobic to hydrophilic or vice versa.
In another embodiment, a frictional property of a planar or curved surface can be changed upon the application of a stimulus.
In another embodiment, the plurality of sections are covered by a polymer.
Disclosed herein is a prosthetic device comprising a sleeve; where a portion of the sleeve comprises a plurality of structural units, wherein each structural unit comprises a first portion; a second portion; wherein the second portion contacts the first portion; and a third portion; wherein the third portion is in communication with the first portion and the second portion and is more compressible than the first portion and the second portion; where the first portion has a first value of a property and where the second portion has a second value of the same property, such that the first value acts as a restraining or enhancing force on the second value; wherein the first portion comprises a first metal and wherein the second portion comprises a second metal that is different from the first metal; where the sleeve is operative to increase in stiffness and to provide support to a body of a living being.
In an embodiment, the sleeve is operative to function as an exoskeleton.
In another embodiment, the sleeve is operative to function as a cast to support a damaged limb.
Disclosed herein is an alloy plate; where the alloy plate is operative to be attached to both ends of a broken bone; where the alloy plate comprises a first portion; a second portion; wherein the second portion contacts the first portion; and a third portion; wherein the third portion is in communication with the first portion and the second portion and is more compressible than the first portion and the second portion; where the first portion has a first value of a property and where the second portion has a second value of the same property, such that the first value acts as a restraining or enhancing force on the second value; wherein the first portion comprises a first metal and wherein the second portion comprises a second metal that is different from the first metal; where body heat causes the plate to contract and retain its original shape, therefore exerting a compressive force on the broken bone at a place of fracture.
Disclosed herein is a tab for an airfoil comprising a first portion; a second portion; wherein the second portion contacts the first portion; and a third portion; wherein the third portion is in communication with the first portion and the second portion and is more compressible than the first portion and the second portion; where the first portion has a first value of a property and where the second portion has a second value of the same property, such that the first value acts as a restraining or enhancing force on the second value; wherein the first portion comprises a first metal and wherein the second portion comprises a second metal that is different from the first metal; wherein the second preset state is different from the first preset state; where a dimension of the tab can be adjusted to stabilize an aircraft.
In an embodiment, the plurality of structural units are periodically spaced.
In another embodiment, the first portion and the second portion comprise a shape memory alloy.
The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:
A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures.
Disclosed herein are articles manufactured via additive manufacturing that comprise at least two portions that are in contact with one another, where each portion has a property that can act as a restraint on the same property displayed by the other portion. The article comprises composite units that contain structural units that comprise a first portion and a second portion that are in contact with one another. The structural units are repeat units that may contain a third portion that is enclosed within the repeat unit and is compressible. The structural units may be periodic or aperiodic. The composite units may also be periodically or aperiodically arranged.
In one embodiment, the article comprises a multi-metallic that contains a first portion, a second portion and a third portion. The multi-metallic may comprise two or more metals, three of more metals, four or more metals, and so on. The multi-metallic may have a shape interface between the two or more different metals. In another embodiment, there may exist a gradient between the different metals that form the respective portions. In one embodiment, the first portion and the second portion (which are in direct contact with one another) both have positive coefficients of thermal expansion but are arranged in such a manner such that the second portion can either absorb an expansion in the first portion to control a dimensional change in the article or alternatively, can restrict (i.e., act as a restraint on) a dimensional change in the first portion that prevents it from achieving its unrestricted value.
In an embodiment, the third portion comprises a material that has a lower stiffness than that the materials used in the first portion and the second portion. In an embodiment, the third portion may be in the form of a continuous matrix that contacts at least the first portion, the second portion or both the first portion and the second portion in each element (repeat unit) of the article. In another embodiment, third portion may comprise isolated voids or partially isolated and non-isolated voids, where the voids contain a material that has a lower elastic modulus or a stiffness than the materials of the first portion and the second portion.
In an embodiment, the articles may be additively manufactured (AM) from a metallic material that may have gas-filled isolated voids or may comprise partially isolated and non-isolated voids (voids open to the surface). When this additively manufactured part is manufactured in a controlled environment, such as in a pressurized/vacuumed chamber, the voids may be filled with a gas of desired pressure. Removing the part from the pressurized/vacuumed chamber would result in some micro-structural (these are referred to as “repeat units” later in this document) deformation. In the case of an oval micro-structure, reduction in the ambient pressure would result in the micro-structure becoming closer to the circular shape (increasing its volume in response to relative pressure applied at both surface sides). The additively manufactured part with micro-structure would be sensitive to ambient pressure and temperature.
As noted above, in a preferred embodiment, the structural units are manufactured from a bimetallic. The materials used in the first portion and the second portion can be bi-metallics. In other words, the first portion has a different coefficient of thermal expansion from the second portion. A bimetal comprises at least two metals. The first portion comprises a first metal, while the second portion comprises a second metal that has a different coefficient of thermal expansion from the first portion. The resulting composite therefore includes two metals that expand at different rates. Examples of the first metal includes copper, iron, aluminum, titanium, tantalum, gold, silver, molybdenum, tungsten, zirconium, platinum, cobalt, vanadium, nickel, or a combination thereof. The second metal can be selected from the aforementioned list but is different from the first metal.
In another embodiment, the article may comprise a shape memory alloy. The first portion and the second portion include shape memory alloy compositions. Shape memory alloys exist in several different temperature-dependent phases. The most commonly utilized of these phases are the so-called martensite and austenite phases. In the following discussion, the martensite phase generally refers to the more deformable, lower temperature phase whereas the austenite phase generally refers to the more rigid, higher temperature phase. When the shape memory alloy is in the martensite phase and is heated, it begins to change into the austenite phase. The temperature at which this phenomenon starts is often referred to as austenite start temperature (As). The temperature at which this phenomenon is complete is called the austenite finish temperature (Af). When the shape memory alloy is in the austenite phase and is cooled, it begins to change into the martensite phase, and the temperature at which this phenomenon starts is referred to as the martensite start temperature (Ms). The temperature at which austenite finishes transforming to martensite is called the martensite finish temperature (MO. Generally, the shape memory alloys are softer and more easily deformable in their martensitic phase and are harder, stiffer, and/or more rigid in the austenitic phase. In view of the foregoing properties, expansion of the shape memory alloy foam is preferably at or below the austenite transition temperature (at or below As). Subsequent heating above the austenite transition temperature causes the expanded shape memory foam to revert back to its permanent (preset) shape and dimensions. Thus, a suitable activation signal for use with shape memory alloys is a thermal activation signal having a magnitude to cause transformations between the martensite and austenite phases.
The temperature at which the shape memory alloy remembers its high temperature form when heated can be adjusted by slight changes in the composition of the alloy and through heat treatment. In nickel-titanium shape memory alloys, for instance, it can be changed from above about 100° C. to below about −100° C. The shape recovery process occurs over a range of just a few degrees and the start or finish of the transformation can be controlled to within a degree or two depending on the desired application and alloy composition. The mechanical properties of the shape memory alloy vary greatly over the temperature range spanning their transformation, typically providing shape memory effects, super elastic effects and high damping capacity.
Suitable shape memory alloy materials for fabricating the first portion and the second portion include, but are not intended to be limited to, nickel-titanium based alloys, indium-titanium based alloys, nickel-aluminum based alloys, nickel-gallium based alloys, copper based alloys (e.g., copper-zinc alloys, copper-aluminum alloys, copper-gold, and copper-tin alloys), gold-cadmium based alloys, silver-cadmium based alloys, indium-cadmium based alloys, manganese-copper based alloys, iron-platinum based alloys, iron-palladium based alloys, and the like. The alloys can be binary, ternary, or any higher order so long as the alloy composition exhibits a shape memory effect, e.g., change in shape orientation, changes in yield strength, and/or flexural modulus properties, damping capacity, superelasticity, and the like. A preferred shape memory alloy is a nickel-titanium based alloy commercially available under the trademark NITINOL from Shape Memory Applications, Inc. Selection of a suitable shape memory alloy composition depends on the temperature range where the component will operate.
As noted above, the first portion has a different preset dimension from the second portion. When the structural unit is activated, the first portion and the second portion undergo a transformation between transformation between the martensite and austenite phases. Since the first portion has a different preset dimension (or shape) from the second portion, the activation causes the first portion to impose a restraining force (or an enhancing force) on the second portion, thus producing a change in the dimensions and/or shape of the structural unit from those dimensions and/or shape that the first portion and the second portion would have if they were not in contact with one another.
For example, if an article that comprises a first portion (with a positive coefficient of thermal expansion) in contact with a second portion (with a positive coefficient of thermal expansion too, but one that is higher than the coefficient of thermal expansion of the first portion) is subjected to an increase in temperature then the first portion can restrain the expansion of the second portion, leading to a change in shape of the article (or distortion of the article). This feature of a first portion acting as a restraint on a second portion (i.e., controlling the expansion of the second portion) may be used to design articles that can display a particular property in response to a change stimulus.
In an embodiment, the article may comprise a plurality of repeating structures (micro-structural units) each of which contains the structure detailed above, i.e., the first portion that controls at least one property of the second portion. The plurality of structural units contact one another in such a manner that the article can be made to expand, contract or remain with its dimensions unchanged upon experiencing a change in temperature or temperature gradient within it, or a combination thereof. The change in ambient conditions may include a change in temperature, pressure, environmental conditions such as the chemical environment, electrical or magnetic conditions, and the like. Each repeating structure generally comprises at least two portions—the first portion and the second portion, but may optionally comprise a third portion, which may form a matrix material. This will be detailed later.
Both the first portion and the second portion are arranged in their respective configurations via additive manufacturing. Additive manufacturing involves the addition of components to an existing structure thereby permitting special configurations that may not be available to other subtractive manufacturing processes (such as milling, grinding, drilling, and so on). Additive Manufacturing (AM)) is a computer-controlled sequential layering of materials to create three-dimensional shapes. A 3D digital model of the item is created, either by computer-aided design (CAD) or using a 3D scanner.
While this disclosure only references articles that comprise a first portion and a second portion, it is understood that an article can comprise more than two portions that influence one another. An article can therefore comprise a plurality of different portions arranged in such a manner so as to restrain or enhance a particular property in a neighboring portion. The net result is that an article that comprises the first and second portions may expand, contract or remained unchanged in shape.
As noted above, there may be a gradient in materials between the first portion and the second portion. In an embodiment, the gradient may be a gradual changing in composition from the metal used in the first portion to the metal used in the second portion. In another embodiment, the gradient may involve two or more step changes in composition from the metal used in the first portion to the metal used in the second portion. Gradients such as linear gradients, curvilinear gradients, and the like, are included herewith. The gradients prevent the delamination of different layers and phases from one another when subjected to varying temperatures. The gradients also facilitate a gradual response (as opposed to a sharp response) when the article is activated.
The
In one embodiment, by choosing the proper weight ratio of the first portion 102 to the second portion 104 and a proper geometry in which to combine with first portion with the second portion, the article can be designed to have no expansion (or contraction) or alternatively, to either expand or contract a desired amount. In another embodiment, by choosing the points of contact and location of the first portion 102 with the second portion, the article can be designed to have no expansion (or contraction) or alternatively, to either expand or contract a desired amount. In yet another embodiment, by choosing the proper weight ratio of the first portion 102 to the second portion 104 and by choosing the points of contact and location of the first portion 102 with the second portion, the article can be designed to have no expansion (or contraction) or alternatively, to either expand or contract a desired amount.
By combining several such first portions 102 with several second portions 104 at different locations as seen in the
From the
In a normal situation, a material with a positive coefficient of temperature expansion) would expand upon experiencing an increase in temperature. In this particular case, the second portion 104 has a lower coefficient of temperature expansion than the first portion 102 and acts as a restraint on the expansion of the first portion 102 when the article 100 is subjected to a temperature increase. This restraint causes the article to shrink in length rather than increase as seen in the
A similar situation may be witnessed in the
From the
The
In an embodiment, the first portion and the second portion detailed above in the
In one embodiment, with reference to the
The compressible material may be a fluid such as air, an inert gas (e.g., nitrogen, carbon dioxide, argon, and the like), a supercritical fluid (e.g., liquid carbon dioxide, and the like), an elastomer (e.g., polyisoprene, polybutadiene, nitrile rubber, and the like), that can undergo compression when the article 100 (comprising the first portion and the second portion) is subjected to changing environmental conditions. The compressible material permits the article to perform its function without any adverse effect on the components (the first portion and the second portion) of the article. In one embodiment, the third portion 110 may form a continuous path through the article 100.
In summary, the repeat units may be combined to form a composite unit. The repeat units may be periodically or aperiodically arranged. The composite units may also be periodically or aperiodically arranged.
Materials used in the articles detailed herein can include shape memory alloys, shape memory polymers, materials having opposed coefficients of thermal expansion, materials having different thermal conductivities, and so on. The resultant articles can have zero thermal expansion or negative thermal expansion when temperature changes occur.
It is to be noted that the repeat units of the article may contain closed cell units (that close on themselves) or open cell units (that do not close on themselves). If the article comprises an open-cell inner structure, the inner core may always be at an ambient pressure and material would be insensitive to pressure changes. However, if that article comprises a close-celled inner structure (each element has a closed volume that encompasses a third portion—where the third portion from adjacent repeat units is not in communication with each other), then its internal pressure may be not equal to the external pressure. In such case, the material becomes pressure, temperature or heat flux sensitive.
Articles that may contain the structures detailed herein include flow control devices (hot water, fire protection fuses), shape varying parts, high precision instruments, fluid conduits with no buildup, biomedical (joints, shunts), electric actuators, ambient conditions (pressure/temperature) controlled actuators, thermal equipment (heat exchangers).
Various applications of the invention will now be described.
The article comprises a skin 706 that surrounds the article. The skin 706 is impermeable to the fluid contained in the conduit. The skin is typically a polymer. The polymers are listed below. Upon application of a stimulus the jaws move closer to one another (or away from each other) thus changing the diameter of the flow area from d1 to d2 (or from d2 to d1), thus changing the volume of flow through the conduit. By applying the appropriate stimulus, the jaw 704 can be closed or opened thus stopping the flow of fluid or alternatively, allowing the fluid to flow through the conduit. The device shown in the
Suitable organic polymers for use in the skin include a wide variety of thermoplastic polymers, blend of thermoplastic polymers, thermosetting polymers, or blends of thermoplastic polymers with thermosetting polymers. The organic polymer may also be a blend of polymers, copolymers, terpolymers, or combinations comprising at least one of the foregoing organic polymers. The organic polymer can also be an oligomer, a homopolymer, a copolymer, a block copolymer, an alternating block copolymer, a random polymer, a random copolymer, a random block copolymer, a graft copolymer, a star block copolymer, a dendrimer, a polyelectrolyte (polymers that have some repeat groups that contain electrolytes), a polyampholyte (a polyelectrolyte having both cationic and anionic repeat groups), an ionomer, or the like, or a combination thereof. The organic polymers have number average molecular weights greater than 10,000 grams per mole, preferably greater than 20,000 g/mole and more preferably greater than 50,000 g/mole.
Exemplary organic polymers include polyacetals, polyacrylics, polycarbonates, polyalkyds, polystyrenes, polyolefins, polyesters, polyamides, polyaramides, polyamideimides, polyarylates, polyurethanes, epoxies, phenolics, silicones, polyarylsulfones, polyethersulfones, polyphenylene sulfides, polysulfones, polyimides, polyetherimides, polytetrafluoroethylenes, polyetherketones, polyether ether ketones, polyether ketone ketones, polybenzoxazoles, polyoxadiazoles, polybenzothiazinophenothiazines, polybenzothiazoles, polypyrazinoquinoxalines, polypyromellitimides, polyguinoxalines, polybenzimidazoles, polyoxindoles, polyoxoisoindolines, polydioxoisoindolines, polytriazines, polypyridazines, polypiperazines, polypyridines, polypiperidines, polytriazoles, polypyrazoles, polycarboranes, polyoxabicyclononanes, polydibenzofurans, polyphthalides, polyacetals, polyanhydrides, polyvinyl ethers, polyvinyl thioethers, polyvinyl alcohols, polyvinyl ketones, polyvinyl halides, polyvinyl nitriles, polyvinyl esters, polysulfonates, polysulfides, polythioesters, polysulfones, polysulfonamides, polyureas, polyphosphazenes, polysilazanes, polypropylenes, polyethylenes, polyethylene terephthalates, polyvinylidene fluorides, polysiloxanes, or the like, or a combination thereof.
The flow control devices may be used to control hot water flow and in fire protection fuses.
In the
The changing of the surface texture can be initiated by using an activating stimulus. The activating stimulus can be a change in temperature or a change in an electrical current or field. Other stimulus such as a change in chemical environment or a change in the acoustic environment can also be used to change the surface texture. The change in surface texture on the inner surface of a conduit may be used to change fluid flow in the conduit from laminar to turbulent.
On flat surfaces such as runways, the hydrophobicity of the surface may be gradually changed. Frictional surfaces can be changed to non-frictional and vice versa. The change can be variable depending upon the magnitude and direction of the applied activating stimulus.
Each of the sections shown in the
This modifying of surface texture may be conducted dynamically. By changing the activation energy, the surface can be changed in real time to modify the surface properties and texture. They can be used in shape varying parts, high precision instruments and in fluid conduits to prevent buildup.
In this application, the rigidity of a device that (contains the article) may be changed by the application of a stimulus. By changing the rigidity of a device, the amount of support for a part of the body (of a living being) can be varied. This permits the device to be used as a cast (to mend a limb when it is sprained or fractured) or to serve as an exo-skeleton (to help a soldier in the battlefield carry a greater load).
In addition, broken bones can be mended with shape memory alloys using the invention described in
The article depicted in the
The principle used in the manufacture of locking devices may also be used in electric actuators and ambient condition (pressure/temperature) controlled actuators.
Performance for helicopter blades depend on vibrations. The article disclosed in the
Articles manufactured by this method can include cylinders and pistons used for internal combustion engines, shrouds, gears, casings, rotors, crankshafts, gears, bearing components and other precision equipment and machinery.
The term “about” is intended to include the degree of error associated with measurement of the particular quantity based upon the equipment available at the time of filing the application.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, element components, and/or groups thereof.
While the present disclosure has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this present disclosure, but that the present disclosure will include all embodiments falling within the scope of the claims.
This application claims the benefit of U.S. Provisional Application No. 63/303,581 filed Jan. 27, 2022, the disclosure of which is incorporated herein by reference in its entirety.
Number | Date | Country | |
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63303581 | Jan 2022 | US |