JP2016539488A - Shape memory alloy conductor that resists plastic deformation - Google Patents

Abstract

Conductors that resist plastic deformation are provided for cables, cable assemblies or devices that carry electronic signals or carry power. The conductive element itself has beneficial mechanical properties and thus combines plastic deformation resistance with conductivity. In one aspect, the superelastic conductor is manufactured using a shape memory alloy such that the transformation temperature of the superelastic conductor is set outside the useful operating range of the conductor. In another embodiment, the conductor is made using a shape memory alloy that is nominally in the martensite phase under stress-free conditions. In both aspects, the conductor microstructure can accommodate externally applied strain, bending, deformation or other external displacements through a mechanism that does not involve plastic deformation.

Description

BACKGROUND Conductors and cables made of conductors are often subjected to external mechanical loads and vibrations. These vibrations and other mechanically or environmentally applied loads often cause strain, deformation, bending or other displacements that occur globally or locally in specific areas over the length of the conductor or cable assembly. Can bring. These large elastic or plastic deformations can in turn detract from the mechanical integrity of conductors or cable assemblies composed of conductors. Specific examples of large elastic or plastic deformations in conductors and cables, as well as the problems they can cause, include distortion localization, work hardening, resulting in torsion, entanglement, and extreme sharp radius permanent bends. Including the repeated strain effects that result, the fatigue life of the conductor or cable or the loss of the final continuity of the cable or conductor through destruction and breakage.

  Shape memory alloys are materials commonly used for their ability to change shape (eg actuators) or the materials for their superelasticity (eyeglass frames, orthodontic bridge wires, It is similar to a mobile phone antenna. Since SMA can adapt to large deformations or strains via reversible phase transformations, they are excellent materials in applications where great flexibility is required. Thus, SMA is used as a reinforcing member for electrical cables, where the role of the SMA element is to keep the cable or wire straight, or to improve the fatigue performance or other mechanical properties of the wire or cable assembly. (US 8399769, US 6717056, US 5275885, US 7093416). In addition, SMA wires are widely used as superelastic wires and cables, where the wire or cable serves only a structural or functional purpose, and any element in the assembly can be an electrical signal, a data signal, It does not conduct electromagnetic signals or power. Such wires have greater flexibility than wires made of common materials such as Fe, Cu and Al, and thus can provide better fatigue and resist local plastic deformation .

  Until now, SMA has been used as a structural reinforcement for electrical cables or wires. In such applications, the SMA element is intended to improve some mechanical properties of the overall cable assembly (eg, resistance to fatigue, torsion) and be transported from one location of the cable to another. Is not an electromagnetic signal, power, data signal or other type of electrical conductor. SMA has also been used as an electrically activated actuator. In this role, current is passed through the SMA wire for the sole purpose of generating heat to induce a phase transformation from martensite to austenite; electrical signals are passed from one place to another. Although not transported, it is used as an indirect means of generating heat via Joule heating.

Summary of the Invention In the present invention, one or more SMA elements (either austenitic or martensitic) are used as a conductor for data signals, electromagnetic waves or power. SMA wire is a good conductor and it also has superior mechanical properties compared to conventional conductors and cables, thus overcoming the limitations of previous conductive structures.

  It is an object of the present invention to provide a conductor and cable or cable assembly that includes or consists of a conductor that resists the deleterious effects of large elastic or plastic deformation. It is a further object of the present invention to provide a conductor material that specifically combines good conductor properties with mechanical properties that resist the adverse effects of large elastic or permanent plastic deformation.

  The practical implications of the present invention are damage resistance, resistance to cable fatigue and premature breakage, resistance to cable kinking and inconvenience of consumer electronics applications, and a highly performance-oriented Or the development and deployment of conductors and cables or cable systems that include or consist of conductors that provide additional safety margins for safety critical applications.

Brief Description of Drawings
FIG. 1 shows kinking of the cable. FIG. 2 shows an example of fatigue failure. FIG. 3 shows typical stress strain curves for the metal 90 commonly used in conducting wires and for the superelastic shape memory alloy 91. The strain indicates that the conventional elastic material 90 can achieve a strain of 0.1-0.9% before accumulating any plastic permanent deformation. The shape memory alloy 91 can achieve a strain approximately equal to 10 times and stretches superelastically to 1-10% strain that is fully recoverable.

FIG. 4 shows a schematic phase diagram for a general shape memory alloy. Austenite is stable on the right hand of four parallel lines, and martensite is stable on the left hand of the line. FIG. 5 shows various form factors for bare superelastic conductors. In one configuration 71, the wire has a circular cross section. In one configuration 72, the wire has a flat cross section, much like a ribbon. In one configuration 73, the wire has an elliptical cross section. FIG. 6 shows a bundle of several individual wires 75 where at least one of the wires is a superelastic conductor and is twisted together to form a wire rope or stranded cable 74. .

FIG. 7 shows an example of a cross section of a cable composed of a superelastic conductive core 29 and an insulating layer 28. In the upper part of the figure, the wire is straight; in the middle part of the figure, the wire is severely deformed; and in the lower part of the figure, the wire is locally deformed and twisted. If the conductor cable is programmed to take a straight shape in the austenite phase, there is no force in the above figure, while the other two wires return to a straight shape if the conductor phase is austenite. Use the power of. If the conductor is martensitic, the conductor is flexible and takes shape changes via martensite plate redistribution. The conductor will return to a straight shape only if sufficient heat or electricity is applied to bring the metal into the austenitic phase. FIG. 8 shows the earphone in two configurations. In the left part of the drawing, the earphone cable does not see any external force and takes a compact shape such as a roll without entanglement. In the right part of the drawing, the cable is used and is therefore extended to connect the jack 37 to the electronic device and the earphone 35 to the human ear. In the right-hand drawing, the earphone cable 36 exerts a small force compared to the stretching force imposed by a human when using the cable. When the right cable lacks any external force, it will again take the shape of the left cable. FIG. 9 shows an example of a composite cable where 29 is a superelastic conductor as described herein, and the other cable 30 is a superelastic conductor or other wire that serves a different purpose. . The cable assembly can be held together by an insulator 31.

Detailed Description of the Invention Cable breakage includes a cable including a conductor, an insulator, an insulation shield (if any), a metal outer shield (if any), and an outermost cable jacket (if distinguishable from the insulator). It occurs in a variety of ways, including failure of any one or more of the various elements that make up. In some cables, the conductor or conductors are simply surrounded directly by an insulator that also serves as an outer protective sheath. In other cables, there may be various layers listed above. Each part of the cable can have its own specific failure mechanism caused by a combination of environmental and load conditions, but the focus of the present invention is to prevent permanent plastic deformation of the conductive element. Will be combined.

  As shown in FIG. 1, large angular deformation can lead to permanent set or twist in the material. Here, the local strain exceeds the yield point of the metal conducting element and therefore there is a permanent deformation. A fatigue scenario can occur if the cable is either forced straight or subjected to reverse strain or reverse bending due to environmental or load conditions. In such a scenario, alternating plastic deformation of the cable can lead to tearing and rupture of the compound that insulates the outer insulator or sheath, as well as fatigue failure of the metal conductor, thereby resulting in fatal failure of the entire cable assembly. There is sex. This is illustrated in FIG.

  It is an object of the present invention to help avoid such strain localization through the use of superelastic conductor elements. The superelastic element has a stress strain curve as shown in FIG. In conventional metals, a small elastic region is followed by a larger plastic region. This elastic strain is 0. This is schematically shown in FIG. 3 by X%. However, the plastic region represents permanent and irreversible deformation. This contributes to cable kinking and eventual fatigue. As shown in FIG. 3, for a superelastic material, the initial elastic region is followed by a large superelastic region. This superelastic region allows the conductor to undergo significant local strain without any permanent strain or permanent plastic deformation in the material, thereby avoiding torsion. In reversing bending and local strain, the cable can again resist permanent deformation until the local strain attempts to exceed or exceed the maximum superelastic strain achievable in the material. it can. Since this can be up to 10 times larger or X%, as shown in FIG. 3, it can accommodate local strain without undergoing permanent plastic deformation, and thereby a significant degree of kinking and There is significant elongation in the conductor's ability to resist local fatigue failure.

  Shape memory alloys (SMAs) are first-order, lattice-distortive diffusionless structural changes that have a shape change where strain energy dominates dynamics and morphology. ) Which is a kind of material exhibiting martensitic transformation. Since their discovery in the 1960s, they have been extensively studied and are currently marketed in the form of wires, sheets, tubes and more complex form factors. Some common alloys that exhibit superelastic and / or shape memory effects are Ni-Ti, Cu-Al-Ni, Cu-Zn-Al, Cu-Al-Be, Cu-Mn-Al, Fe-Mn. -Si, Ni-Mn-Ga, but there are many others and more alloy systems are also expected to be discovered in the future. Among the most commercially successful applications of these materials are spectacle frames, orthodontic bridge wires, various actuators, bra underwires, mobile phone antennas, medical stents, endodontic treatments. File (endodontic file), drug delivery micropump and so on. Most commercial applications use either binary Ni—Ti or Ni—Ti with alloy additions from elements such as Cu, Pd, Pt, Hf or others. The present invention is not limited to a particular alloy system. Rather it applies to any SMA system with an electrical resistivity lower than about 500 n-ohm-m. Table 1 provides a non-limiting list of various alloy systems that can be used as flexible conductors according to the present invention.

  SMA is characterized by a solid-to-solid reversible phase transformation between a higher temperature phase called austenite and a lower temperature phase called martensite. In most SMAs, austenite represents a superlattice structure with a body-centered cubic (bcc) sublattice. Since the higher temperature austenite lattice has higher crystallographic symmetry than the lower temperature martensite, there are multiple symmetry related variants in martensite. Using Cu-Zn-Al as an example, austenite can be transformed into 12 different variants of martensite. Often, the entire crystal is transformed from austenite to a single variant of martensite, but rather to various variants of complex arrangement. Under some conditions, when austenite crystals are cooled to a temperature range where martensite is a stable phase, martensite is formed by nucleation and growth; martensite is thermally induced. Mechanical forces also induce phase transformations at isothermal conditions, in which case martensite is said to be stress-induced. The application of thermal or mechanical stimuli that cause shape changes is closely related to the shape memory effect (SME) and superelasticity (SE), respectively.

FIG. 4 shows a schematic phase diagram that applies to all SMAs and illustrates characteristic temperatures and stresses. For austenite, the right hand of the four parallel lines in FIG. 4 is the stable phase, while for martensite, the left hand of the four parallel lines is the stable phase. In other words, this figure shows that martensite is stable at relatively lower temperatures and higher stress, whereas austenite is stable at higher temperatures and lower stress. . The absolute position of the transformation temperatures A _f , A _s , M _s and M _f (respectively austenite end, austenite start, martensite start, martensite end) depends on several factors including the alloy composition. The crystal structure shown in FIG. 4 is schematic; they show how a martensitic variant can be transformed into a second martensitic variant when subjected to stress. The arrows indicate whether the change in crystal structure is reversed when the transformation path is reversed; after applying stress to the martensite plate to transform the martensite plate to a different plate, the first plate is When the stress is relaxed, it is generally not recovered.

Superelasticity is a term used to describe a stress-induced phase transformation. At a certain temperature at which austenite is a stable phase, the martensitic transformation is immediately induced by stress. This transformation path is indicated by a vertical double arrow in FIG. When the external stress is removed, the martensite returns to austenite and macroscopic deformation is restored. Note that conventional plastic deformation occurs when the stress inducing martensite exceeds the critical stress of slip. Thus, superelasticity is possible only in a relatively small temperature range above _Af . Similarly, both forward and reverse transformations occur gradually for the thermal transformation: the forward transformation starts at the martensite onset stress σ _{Ms and} at the higher martensite end stress σ _Mf . Completion; reverse transformation starts at austenite start stress σ _{As and} ends at austenite end stress σ _Af . Furthermore, we note that it is clear that a complete transformation cycle always exhibits a hysteresis because σ _As <σ _Mf and σ _Af <σ _Ms. Hysteresis is related to thermodynamic irreversibility and reflects the energy dissipated as heat due to the frictional work expended on the movement of the austenite / martensite interface. The transformation strain can vary from about 2 to 10%, and the transformation stress varies from about 20 to 500 MPa depending on the alloy, temperature, microstructure, strain rate, orientation, etc.

  It is noteworthy that deformations that can be up to 10% are accommodated purely by phase transformations and that there is essentially no expectation of conventional plasticity through the occurrence and migration of delocalization. Thus, SMAs can adapt to large strains without breaking and it can also be done repeatedly; their fatigue performance at high strains is much greater than regular metals The material resists fatigue failure by avoiding local plastic deformation. In addition, superelastic materials exert a repulsive force when subjected to deformation, which repel force attempts to return the material to its undeformed shape; the material resists twisting. For example, when twist is introduced into a straight superelastic wire, the material transforms from austenite to martensite locally at the kink, but returns to a straight shape when there is no stress.

  Martensitic material refers to SMA in martensitic kinetics illustrated in FIG. 4 (on the left hand side of four parallel lines). When subjected to deformation, the martensitic material will deform through redistribution of the martensite plate. Because there are several martensitic mutants in a symmetric relationship, they can be easily transformed between each other to accommodate shape changes. However, unlike superelasticity, martensitic materials do not return to their original shape even when external mechanical stimuli are removed. Like superelasticity, martensitic SMA also avoids conventional plastic deformation and damage accumulation.

  Both martensitic and austenitic SMAs can be trained to take a number of predetermined shapes. For example, a martensitic material can be given a shape; it will operate as described above with the ability to take a different shape through the rearrangement of martensitic mutants; Once done, it will take the predetermined shape by transforming to austenite. For example, the material is manufactured and heat treated so that the austenite shape is in the form of a circular spool of wire and the transformation temperature is above the operating temperature. In use, the material is martensite; the material may be deformed and stretched to any particular shape, such as a straight shape; if it is desired to restore a spooled configuration The wire can be subjected to mild heat and electricity; when the temperature brings the wire to austenite kinetics (see FIG. 4), the rolled up circular shape is restored.

  The superelastic conductor may have a circular cross section, but may be flat or elliptical, or have other cross sectional shapes, as desired. Three cross sections are shown in FIG. 5, where 71 indicates a circular cross section, 72 indicates a flat ribbon-like cross section, and 73 indicates a wire with an elliptical cross section. The wire may be a single bare or insulated wire or part of a cable or wire rope. FIG. 6 illustrates an example of how this can be done; some individual wires 75 are now insulated or bare, although at least one is a super-elastic conductor and is insulated or bare. Are twisted together to form This can further improve mechanical properties such as fatigue and strength, which can add functionality, power or bandwidth to the cable.

  In this aspect of the invention, an operating temperature range is contemplated where the lead is austenitic. The wire may or may not be supplied in a specified shape (eg, straight, round, twisted). In normal mode of operation, the wire may or may not be subjected to extreme mechanical stimuli such as tension, vibration, twisting, bending or others, and austenitic wire can easily conduct current. You don't have to. When subjected to mechanical inputs such as vibration, bending, tension, compression or others, the wire can adapt to this strain by transforming locally to martensite. For example, in a vibrating assembly, the majority of the wire can be distorted and transformed; if bent or twisted, the transformation can be local. In both cases, conventional plastic deformation does not occur and the wire is not damaged. When the mechanical stimulus stops (eg, the vibration stops or the force that causes twisting is removed), the wire will recover its original predetermined shape and the martensite is transformed back to austenite. . This prevents entanglement, fracture and fatigue failure at large strains.

  The strain that can be achieved is locally on the order of 2-10%. The resilience, in other words resistance to twisting and deformation, can be adjusted in the range of 10 MPa to 800 MPa depending on the composition and temperature and transformation temperature. FIG. 7 shows several configurations of a wire with an insulator; the wire is supplied in one preferred shape, and any local or global deformation will cause a repulsive force by the wire; Exerts a force to return to the preferred shape.

  In this aspect of the invention, the material is manufactured to be in the martensite phase under normal operating conditions. The material is therefore highly flexible and can accommodate large shape changes with strains as high as 10%. The advantage of this over conventional signal or power wires is that it can be deformed to much higher strains without accumulating microstructure damage; and it does so repeatedly. Can do. Further, the predetermined shape can be recovered in the following manner: The martensitic wire is heated via direct heating or Joule heating or other mechanism such that the martensite transforms into austenite; The austenite shape is manufactured in such a way that it takes several known forms. Now, the wire in the desired form cools back to the original martensite while maintaining the desired form (i.e., the thermal transformation from austenite to martensite is known as the self-fit of the martensite variant. Does not bring about a macroscopic shape change due to the phenomenon). The material again becomes martensitic and can be used as appropriate. FIG. 6 shows several configurations of wires with insulators. The wire is supplied in one preferred shape that can only be reached at temperatures above the intended operating range. The wire may be deformed locally or globally through the redistribution of martensitic mutants, which redistribution does not provide resilience and does not involve conventional plasticity. The restoring force only works when the wire raises its temperature above the transformation temperature.

  The following example shows how the present invention can be used to create a conductor for electromagnetic signals both as a flexible but untwisted cable and a functional wire with some specific shape memory Explain how. Conductors that transport electromagnetic signals from one end to the other are made of austenitic superelastic alloys. The signal may be transported from an electronic device such as a mobile phone, digital music player, tablet computer, personal computer, stereo music system, amplifier, mp3 player or others. The signal can be transported to speakers, earphones, headphones or another electronic device. The length of the cable can be short (eg several centimeters) or long (several hundred meters), intermediate length (eg about 1-2 meters, about 1 meter, about 2 meters or about 3 meters) It may be. The cable may be bare or insulated. The conductor may or may not be braided and may be placed with other cables or ropes having other functions.

  The conductor is austenitic and therefore has a preferred shape at the operating temperature; this shape may be straight or circular and the cable is rounded, compact or has some other function. It may be in some preferred shape. Since the cable is austenitic, it will resist deformation; this resistance may be programmed to be small or large. In one aspect of the invention, the recovery force may be small so that deformation is easily imposed by a person, and the wire may be stretched to take on different shapes with a small force. The conductor returns to its predetermined shape when left without any external force.

  In one aspect of the invention, the wire may be connected to an earphone or headphone and the preferred shape may be a compact shape such as a circular roll that fits well in a pocket or dispenser device and is tangled. Good. This is illustrated in FIG. 8, where the wire is wound into a predetermined shape under no external mechanical force. Instead of tangling into difficult shapes that are difficult to straighten, the wires return to the preferred shape when not in use. When used (eg, stretched to position one end in a pocket and the other in an ear), the wire is straight and does not tend to entangle. This is illustrated in the drawing on the right side of FIG. 8, where the wire is stretched, the earphone is inserted into the human ear, and the plug or connector is inserted into the jack or connector of the electronic device. Has been. When left without any external force, such as on a table or other surface, the wire is rolled up and returned to an untangled configuration.

  A wire may be bare or insulated, it is a single containing multiple wires or other wires with complementary or independent functions that may be electrical, functional, structural or otherwise It can be part of a single-wire or cable. FIG. 9 shows an example of a wire that is part of a larger assembly of wires with similar complementary or independent functions. The assembly may be bare, insulated, or embedded in a composite or polymer matrix. The superelastic conductor may further be woven or knitted into a 2D or 3D structure, or it may be twisted or twisted into a spiral, thus forming a wire rope. .

  The shape memory alloy material of the present invention can be either polycrystalline, monocrystalline or oligocrystalline, as defined by US Pat. No. 8,282,746.

Claims (60)

  A superelastic conductor comprising a shape memory alloy material, wherein the shape memory alloy material has an electrical resistivity of less than 500 nano ohm meters and carries a data signal or provides power or The conductor configured to be both.   The conductor of claim 1 carrying a direct current or alternating current waveform having a voltage in the range of about 0V to about 10V and a current in the range of 0 to about 20 milliamps.   The conductor of claim 2, capable of transmitting a signal having a frequency ranging from DC to about 10 GHz.   The conductor of claim 1, capable of carrying a digitally encoded signal.   The conductor of claim 1, capable of carrying a voltage of 100V or greater.   The conductor of claim 1, having a cross-sectional dimension ranging from about 10 micrometers to about 10,000 micrometers.   The conductor of claim 1, wherein the material is substantially in the austenite phase when stress free.   When the material is unstressed, it is substantially in the austenite phase, but when subjected to global or local bending, strain or other externally applied deformation, it substantially transforms into the martensite phase. And the conductor of claim 1 adapted to such externally applied deformation through the phase transformation.   The conductor of claim 1, wherein the shape memory alloy has a transformation temperature at or below the intended operating temperature of the conductor.   The conductor of claim 1, configured for use as a single conductor.   The conductor of claim 1, configured as a bare wire.   The conductor of claim 1, configured as the wire with an electrically insulating coating covering substantially or completely the length of the wire.   The conductor of claim 1 configured as a pair of conductors for use in audio applications.   The conductor of claim 1 configured as part of a multi-conductor cable with or without a shield, wherein each individual conductor is a solid conductor.   The conductor according to claim 1, wherein the conductor is configured as a part of a stranded cable.   The conductor of claim 1 configured as part of a coaxial cable.   The conductor of claim 1, configured as a flat ribbon. Shape memory alloys are the following alloys:

The conductor of claim 1 selected from the group consisting of:   The conductor of claim 18, wherein the shape memory alloy is polycrystalline.   The conductor of claim 18, wherein the shape memory alloy is single crystalline.   The conductor of claim 18, wherein the material is oligocrystalline.   A shape memory alloy conductor comprising a shape memory alloy, wherein the shape memory alloy is substantially in the martensitic phase under stress-free conditions and has an electrical resistivity of less than 500 nano ohm meters And the shape memory alloy conductor configured to carry data signals or supply power or both.   23. The conductor of claim 22, carrying a direct current or alternating current waveform having a voltage in the range of about 0V to about 10V and a current in the range of 0 to about 20 milliamps.   24. The conductor of claim 23, capable of transmitting a signal having a frequency in the range from DC to about 10 GHz.   23. A conductor according to claim 22, capable of carrying a digitally encoded signal.   24. The conductor of claim 22 capable of carrying a voltage of 100V or greater.   23. The conductor of claim 22, having a cross-sectional dimension in the range of about 10 micrometers to about 10,000 micrometers.   23. A conductor according to claim 22, wherein the shape memory alloy has a transformation temperature at or above the intended operating temperature of the conductor.   23. A conductor according to claim 22 configured for use as a single conductor.   23. A conductor according to claim 22 configured as a bare wire.   23. A conductor according to claim 22 configured as said wire with an electrically insulating coating covering substantially or completely the length of the wire.   24. The conductor of claim 22 configured as a pair of conductors for use in audio applications.   23. A conductor according to claim 22 configured as part of a multi-conductor cable with or without shielding, wherein each individual conductor is a solid conductor.   23. A conductor according to claim 22 configured as part of a stranded wire cable.   23. A conductor according to claim 22 configured as part of a coaxial cable.   The conductor of claim 22 configured as a flat ribbon. Shape memory alloys are the following alloys:
24. The conductor of claim 22, wherein the conductor is selected from the group consisting of:   38. The conductor of claim 37, wherein the shape memory alloy is polycrystalline.   38. The conductor of claim 37, wherein the shape memory alloy is single crystalline.   38. The conductor of claim 37, wherein the material is oligocrystalline.   A cable carrying or distributing signal assembly comprising a conductor that resists plastic deformation, wherein the conductor is in a superelastic state.   42. The cable assembly of claim 41, carrying a direct current or alternating current waveform having a voltage in the range of about 0V to about 10V and a current in the range of 0 to about 20 milliamps.   42. The cable assembly of claim 41, capable of transmitting a signal having a frequency in a range from DC to about 10 GHz.   42. The cable assembly of claim 41, capable of carrying a digitally encoded signal.   42. The cable assembly of claim 41, capable of carrying a voltage of 100V or greater.   42. The cable assembly of claim 41, wherein the conductor resists plastic deformation (transformation between austenite and martensite phases) via superelasticity.   42. The cable assembly of claim 41, wherein the conductor resists plastic deformation through movement of the martensite plate.   42. The cable assembly of claim 41, configured for use with audio headphones, earphones, or other electromagnetic devices that carry electrically encoded audio information to the human ear.   42. The system of claim 41, configured for use as a speaker wire or wired cable that transmits electrically encoded audio information to an electromagnetic system that converts the encoded audio information back to sound. Cable assembly.   42. The cable assembly of claim 41, configured for use in a high vibration load environment.   42. The cable assembly of claim 41, configured for use as an aerospace application including data signal transmission or power distribution.   42. The cable of claim 41, configured for use in a weapon system subjected to ballistic recoil or other intermittent high amplitude impact loads, either for transmission of data signals or distribution. assembly.   42. The cable assembly of claim 41, configured for use in an automotive wiring harness assembly for either data signal transmission or power distribution.   42. The cable of claim 41, configured for use in a wire or cable assembly for downhole measurements, used in an oil and gas assembly, either for transmission of data signals or power distribution. assembly.   Use in wires and cable assemblies used in computers or computer boards, either as internal to the computer or external cables that provide power or data to the computer, either for transmission of data signals or distribution 42. The cable assembly of claim 41, configured for.   42. A cable assembly according to claim 41, configured for use in wiring or power distribution for railway, commuter train or other rail applications, either for transmission of data signals or power distribution.   Configured for applications where the shape memory alloy is trained to return to a particular shape or configuration using thermal processing when the cable assembly is not in use or in an unstressed state; 42. A cable assembly according to claim 41.   42. The device of claim 41, wherein the shape memory alloy is configured for an application that is capable of restoring or returning to shape when subjected to a change in temperature that is different from an intended use temperature. Cable assembly.   59. A cable assembly according to claim 58, wherein the change in temperature is electrically actuated via resistive heating of the superelastic conductor.   59. The cable assembly of claim 58, wherein the change in temperature is caused by a change in ambient temperature.