Precipitation-strengthened shape memory alloys, designing methods and applications of same

Patent metadata

Field	Value
Publication number	US-12024760-B2
Application number	US-202318109379-A
Country	US
Kind code	B2
Filing date	Feb 14, 2023
Priority date	Feb 14, 2022
Publication date	Jul 2, 2024
Grant date	Jul 2, 2024

Abstract

The invention relates to a precipitation-strengthened shape memory alloy (SMA) comprising a composition designed and processed such that the precipitation-strengthened SMA meets property objectives comprising a yield strength being more than about 1500 MPa at room temperature, a transformation temperature in a range of about −15 to 20° C., a misfit in a range of about 0.9-1.1%, wherein the property objectives are design specifications of the precipitation-strengthened SMA.

First claim

What is claimed is:

1. A precipitation-strengthened shape memory alloy (SMA), comprising:
a composition designed and processed such that the precipitation-strengthened SMA meets property objectives comprising a yield strength being more than about 1500 MPa at room temperature, a transformation temperature in a range of about −15 to 20° C. misfit in a range of about 0.9-1.1%,
wherein the property objectives are design specifications of the precipitation-strengthened SMA;
wherein the precipitation-strengthened SMA comprises an Ni 50 Ti 23.8 Hf 21.8 Al 4.4 alloy that is superelastic at room temperature; and
wherein the yield strength is about 1770 MPa at room temperature, the transformation temperature is about −10° C., the misfit about 1.02% and the hot cracking sensitivity about 0.3.

2. The precipitation-strengthened SMA of claim 1 , wherein the composition is processed with a heat-treatment process including homogenization and solution treatment at about 1050° C. for about 72h followed by water quenching; and aging treatment at about 600° C. for about 10h followed by water quenching.

3. The precipitation-strengthened SMA of claim 1 , having a maximum recoverable strain about 4.2% in a wide temperature range from room temperature to about 175° C.

4. A precipitation-strengthened shape memory alloy (SMA), comprising:
a composition designed and processed such that the precipitation-strengthened SMA meets property objectives comprising a yield strength being more than about 1500 MPa at room temperature, a transformation temperature in a range of about −15 to 20° C., a misfit in a range of about 0.9-1.1%,
wherein the property objectives are design specifications of the precipitation-strengthened SMA;
wherein the precipitation-strengthened SMA comprises an Ni 50 Ti 24 Hf 22 Al 4 alloy;
and wherein the yield strength is about 1680 MPa at room temperature, the transformation temperature is about 15 the misfit about 1.03%, and the hot cracking sensitivity about 0.3.

5. The precipitation-strengthened SMA of claim 4 , wherein the Ni 50 Ti 24 Hf 22 Al 4 alloy aged at about 600° C. for about 10h is of a B2-L2 1 two-phase structure.

Assignees

• Univ Northwestern

Inventors

• Liu Chuan
• Olson Gregory B

Classifications

• C22F1/10

  of nickel or cobalt or alloys based thereon · CPC title

• C22C19/03

  based on nickel · CPC title

• C22F1/002

  by rapid cooling or quenching; cooling agents used therefor · CPC title

• C22F1/16

  of other metals or alloys based thereon · CPC title

• C22F1/006

  Resulting in heat recoverable alloys with a memory effect · CPC title