# US 10,119,176 B2 · Superelastic wire and method of formation

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- Number: US 10,119,176 B2
- Document ID: US10119176B2
- Status: Granted
- Kind: B2
- Application number: 13/328,362
- Filed: 2011-12-16
- Published: 2013-06-20
- Granted: 2018-11-06
- Earliest claimed: 2011-12-16
- Assignees: Raytheon Company
- Applicants: Sunder S. Rajan
- Inventors: Sunder S. Rajan
- Web page: https://patentgrep.com/patent/US10119176B2

## CPC

- C21D 9/52: for wires; for strips {; for rods of unlimited length}
- C22C 19/007: {with a light metal (alkali metal Li, Na, K, Rb, Cs; earth alkali metal Be, Mg, Ca, Sr, Ba, Al Ga, Ge, Ti) or B, Si, Zr, Hf, Sc, Y, lanthanides, actinides, as the next major constituent}
- C22C 19/03: based on nickel
- C22F 1/00: Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working (apparatus for mechanical working of metal B21, B23, B24)
- C22F 1/10: of nickel or cobalt or alloys based thereon
- H01Q 1/1235: {Collapsible supports; Means for erecting a rigid antenna}
- H01Q 19/13: the primary radiating source being a single radiating element, e.g. a dipole, a slot, a waveguide termination (H01Q19/15 takes precedence)
- C21D: MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass C23F17/00; unidirectional solidification of eutectic materials or unidirectional demixing of eutectoid materials C30B)
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- C22F: CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass, C23F17/00)
- H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72)

## Abstract

A shape memory alloy including a Ni—Ti based alloy is superelastic at temperatures of about −40° C. to about 60° C. after being exposed to temperatures of about −55° C. to about 85° C. A method of forming a memory shape alloy may include preparing a rod comprising a Ni—Ti alloy, drawing a wire from the rod, and treating the wire at a temperature of about 500° C. to about 550° C. for about less than 1 minute.

## Claims

### Claim 1

A shape memory alloy comprising:
a Ni—Ti based alloy, wherein the Ni—Ti based alloy is superelastic at temperatures of −40° C. to about 60° C. after being exposed to temperatures of about −55° C. to about 85° C.,
wherein the Ni—Ti based alloy has an ultimate tensile strength of about 200 KSI (about 1.38 GPa) to about 211 KSI (about 1.45 GPa).

### Claim 2 (depends on 1)

The shape memory alloy of claim 1, wherein the Ni—Ti based alloy is superelastic at temperatures of −40° C. to about 60° C. after being exposed to temperatures of about −55° C. to about 85° C. under up to about a 6% strain.

### Claim 3 (depends on 1)

The shape memory alloy of claim 1, wherein the Ni—Ti based alloy has an austenite start temperature of about −60° C. and an austenite finish temperature of from −20° C. to 5° C.

### Claim 4 (depends on 1)

The shape memory alloy of claim 1, wherein the Ni—Ti based alloy comprises about 54.5 wt % to about 57 wt % Ni, the balance being Ti and impurities.

### Claim 5 (depends on 1)

The shape memory alloy of claim 1, wherein the Ni—Ti based alloy has a strain induced martensite transformation temperature of greater than about 60° C.

### Claim 6 (depends on 1)

The shape memory alloy of claim 1, wherein the Ni—Ti based alloy is a wire having a diameter of equal to or greater than 0.008 inches (about 0.02 mm) and equal to or less than 0.024 inches (about 0.6 mm).

### Claim 7 (depends on 1)

The shape memory alloy of claim 1, wherein the Ni—Ti based alloy has an upper plateau stress at 3% strain of greater than about 80 KSI (about 0.55MPa).

### Claim 8 (depends on 1)

The shape memory alloy of claim 1, wherein the Ni—Ti based alloy has an austenite finish temperature of about 5° C.

### Claim 9 (depends on 1)

A stowable antenna comprising wires comprising the shape memory alloy of claim 1.

### Claim 10

A method of forming a shape memory alloy comprising:
preparing a rod comprising a Ni—Ti based alloy;
wherein the Ni-Ti based alloy is superelastic at temperatures of −40° C. to about 60° C. after being exposed to temperatures of about −55° C. to about 85° C., and wherein the Ni-Ti based alloy has an ultimate tensile strength of about 200 KSI (about 1.38 GPa) to about 211 KSI (about 1.45 GPa);
drawing a wire from the rod; and
treating the wire at a temperature of about 500° C. to about 550° C. for about less than 1 minute.

### Claim 11 (depends on 10)

The method of claim 10, wherein the treating the wire is performed for about 15 to about 45 seconds.

### Claim 12 (depends on 10)

The method of claim 10, wherein the treated wire has an austenite start temperature of about −60° C. and an austenite finish temperature of from about −20° C. to about 5° C.

### Claim 13 (depends on 12)

The method of claim 12, wherein the austenite finish temperature is about 5° C.

### Claim 14 (depends on 10)

The method of claim 10, wherein the treated wire is superelastic at temperatures of −40° C. to about 60° C. after being exposed to temperatures of about −55° C. to about 85° C.

### Claim 15 (depends on 10)

The method of claim 10, wherein the treated wire is superelastic at temperatures of −40° C. to about 60° C. after being exposed to temperatures of about −55° C. to about 85° C. under up to about a 6% strain.

### Claim 16 (depends on 10)

The method of claim 10, wherein the treating the wire comprises drawing the alloy through an oven.

### Claim 17 (depends on 10)

The method of claim 10, wherein the wire has a diameter of greater than equal to 0.008 inches (about 0.02 mm) and equal to or less than 0.024 inches (about 0.6 mm).

### Claim 18 (depends on 10)

The method of claim 10, wherein the treated wire has a strain induced martensite transformation temperature of greater than about 60° C.

### Claim 19 (depends on 10)

The method of claim 10, wherein the Ni—Ti alloy comprises about 54.5 wt % to about 57 wt % Ni, the balance being Ti and impurities.