Superelastic alloy

Patent metadata

Field	Value
Publication number	US-10590519-B2
Application number	US-201414913810-A
Country	US
Kind code	B2
Filing date	Aug 29, 2014
Priority date	Aug 30, 2013
Publication date	Mar 17, 2020
Grant date	Mar 17, 2020

Abstract

The present invention provides a superelastic alloy formed by addition of Fe or Co to an Au—Cu—Al alloy, including: Cu of 12.5% by mass or more and 16.5% by mass or less; Al of 3.0% by mass or more and 5.5% by mass or less; Fe or Co of 0.01% by mass or more and 2.0% by mass or less; and a balance Au, and a difference between Al content and Cu content (Cu—Al) is 12% by mass or less. The superelastic alloy according to the present invention has superelastic property while being Ni-free, excellent X-ray imaging property, processability, and strength property, and is suitable for a medical field.

First claim

The invention claimed is:

1. A superelastic alloy formed by addition of Fe to an Au—Cu—Al alloy, wherein the superelastic alloy comprises:
Cu of 12.5% by mass or more and 16.5% by mass or less;
Al of 3.1% by mass or more and 5.5% by mass or less;
Fe of 0.9% by mass or more and 2.0% by mass or less;
a balance of Au, and further wherein a difference between the Al content and the Cu content (Cu—Al) is 12% by mass or less: and
wherein the superelastic alloy has a superelastic shape recovery rate of 40% or more calculated by a following equation based on a plastic strain at the time of 2% strain measured when the superelastic alloy is subjected to a tensile test and an unloaded residual strain:
Superelastic shape recovery rate (%)=(plastic strain (%) at the time of 2% strain−residual strain (%))/plastic strain at the time of 2% strain×100  [Equation 1]

wherein plastic strain is a value obtained by exclusion of an elastic deformation strain from a total deformation strain.

2. The superelastic alloy according to claim 1 , wherein the Au content is 78.7% by mass or more and 83.1% by mass or less.

3. A method of manufacturing the superelastic alloy according to claim 1 , comprising the steps of:
melting and casting an alloy including
Cu of 12.5% by mass or more and 16.5% by mass or less,
Al of 3.1% by mass or more and 5.5% by mass or less,
Fe of 0.9% by mass or more and 2.0% by mass or less, and
a balance of Au; and
performing a final heat treatment of heating and maintaining the alloy at 300 to 500° C. and then quenching the alloy.

4. The method of manufacturing the superelastic alloy according to claim 3 , comprising the step of cold working the alloy before the step of the final heat treatment.

5. A method of manufacturing the superelastic alloy according to claim 2 , comprising the steps of:
melting and casting an alloy including
Cu of 12.5% by mass or more and 16.5% by mass or less,
Al of 3.1% by mass or more and 5.5% by mass or less,
Fe of 0.9% by mass or more and 2.0% by mass or less, and a balance of Au, wherein the Au content is 78.7% by mass or more and 83.1% by mass or less; and
performing a final heat treatment of heating and maintaining the alloy at 300 to 500° C. and then quenching the alloy.

Assignees

• Tanaka Precious Metal Ind
• Tokyo Inst Tech

Inventors

• HOSADA Hideki
• Inamura Tomonari
• Tahara Masaki
• Morita Tomohiko
• Umise Akira
• Doi Yusuke
• Goto Kenji

Classifications

• B22D21/005

  with high melting point, e.g. Be 1280 degrees C, Ti 1725 degrees C · CPC title

• C22F1/14 Primary

  of noble metals or alloys based thereon · CPC title

• C22C1/02

  by melting {(C22C1/1036 takes precedence)} · CPC title

• C21D2201/01

  Shape memory effect · CPC title

• C22C5/02 Primary

  Alloys based on gold · CPC title