Method of forming a sintered nickel-titanium-rare earth (Ni—Ti—RE) alloy

Patent metadata

Field	Value
Publication number	US-10000827-B2
Application number	US-201213656151-A
Country	US
Kind code	B2
Filing date	Oct 19, 2012
Priority date	Oct 21, 2011
Publication date	Jun 19, 2018
Grant date	Jun 19, 2018

Abstract

A method of forming a sintered nickel-titanium-rare earth (Ni—Ti-RE) alloy includes adding one or more powders comprising Ni, Ti, and a rare earth constituent to a powder consolidation unit comprising an electrically conductive die and punch connectable to a power supply. The one or more powders are heated at a ramp rate of about 35° C./min or less to a sintering temperature, and pressure is applied to the powders at the sintering temperature, thereby forming a sintered Ni—Ti-RE alloy.

First claim

The invention claimed is:

1. A method of forming a sintered nickel-titanium-rare earth (Ni—Ti-RE) alloy, the method comprising:
adding one or more powders comprising Ni, Ti, and a rare earth element consisting of Er to a powder consolidation unit comprising an electrically conductive die and punch connectable to a power supply;
heating the one or more powders at a ramp rate of about 35° C./min or less to a sintering temperature within a softening temperature range of the rare earth constituent, the softening temperature range being equal to between about 0.5·T m and about 0.55·T m , where T m is an absolute melting temperature of the rare earth constituent in degrees Celsius;
applying pressure to the powders at the sintering temperature; and
forming a sintered Ni—Ti-RE alloy comprising the Ni at a concentration from about 34 at. % to about 60 at. %, comprising the Ti at a concentration from about 34 at. % to about 60 at. %, and comprising the Er at a concentration from about 0.1 at. % to about 15 at. %; and
hot working the sintered Ni—Ti-RE alloy.

2. The method of claim 1 , wherein heating the one or more powders comprises passing a pulsed electrical current through the one or more powders.

3. The method of claim 1 , wherein the pressure lies between about 45 MPa and about 110 MPa.

4. The method of claim 1 , wherein the sintered Ni—Ti-RE alloy has a density of at least about 95% of theoretical density.

5. The method of claim 1 , wherein the one or more powders include elemental Ni powders and elemental Ti powders.

6. The method of claim 1 , wherein the one or more powders include prealloyed Ni—Ti powders.

7. The method of claim 1 , wherein the one or more powders include prealloyed Er-X powders, where X is an element selected from Ag and Au.

8. The method of claim 1 , wherein the one or more powders include elemental Er powders.

9. The method of claim 1 , wherein the one or more powders includes a dopant comprising B.

10. The method of claim 1 , wherein the hot working comprises hot rolling.

Assignees

• Univ Limerick

Inventors

• Tofail Syed Ansar Md
• Butler James

Classifications

• B22F3/105

  by using electric current {other than for infrared radiant energy}, laser radiation or plasma (B22F3/11 takes precedence){; by ultrasonic bonding (B22F3/115 takes precedence)} · CPC title

• C22C19/03

  based on nickel · CPC title

• C22C19/007 Primary

  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 · CPC title

• C22C1/0441

  Alloys based on intermetallic compounds of the type rare earth - Co, Ni · CPC title

• C22C1/0433 Primary

  Nickel- or cobalt-based alloys · CPC title