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

Patent metadata

Field	Value
Publication number	US-10563291-B2
Application number	US-201815978921-A
Country	US
Kind code	B2
Filing date	May 14, 2018
Priority date	Oct 21, 2011
Publication date	Feb 18, 2020
Grant date	Feb 18, 2020

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 sintered nickel-titanium-rare earth (Ni—Ti-RE) alloy comprising:
Ni at a concentration of from 35 at. % to 65 at. %;
Ti at a concentration of from 35 at. % to 65 at. %; and
a rare earth (RE) constituent at a concentration of from 1.5 at. % to about 15 at. %,
wherein the sintered Ni—Ti-RE alloy includes a matrix phase and a second phase, the second phase comprising discrete regions in the matrix phase and including a RE element, and
wherein the sintered Ni—Ti-RE alloy is superelastic at body temperature.

2. The sintered Ni—Ti-RE alloy of claim 1 , wherein the alloy further comprises an additional alloying element selected from the group consisting of Al, Cr, Mn, Fe, Co, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, TI, Pb, Bi, Po, and V.

3. The sintered Ni—Ti-RE alloy of claim 2 , wherein the second phase has a formula M x RE y , where M is the additional alloying element.

4. The sintered Ni—Ti-RE alloy of claim 2 , wherein the additional alloying element is selected from the group consisting of Fe and Ag.

5. The sintered Ni—Ti-RE alloy of claim 1 , wherein the second phase has a formula RE x Ni y .

6. The sintered Ni—Ti-RE alloy of claim 1 , wherein the rare earth element is selected from the group consisting of Dy, Er, Gd, Ho, La, Lu, Sc, Sm, Tb, Tm, Y, and Yb.

7. The sintered Ni—Ti-RE alloy of claim 6 , wherein the rare earth element comprises erbium.

8. The sintered Ni—Ti-RE alloy of claim 1 further comprising boron (B).

9. The sintered Ni—Ti-RE alloy of claim 1 , wherein the matrix includes NiTi.

10. The sintered Ni—Ti-RE alloy of claim 1 , wherein the discrete regions of the second phase have an average size from 1 micron to 500 microns.

11. The sintered Ni—Ti-RE alloy of claim 10 , wherein the average size is from 1 micron to 150 microns.

12. The sintered Ni—Ti-RE alloy of claim 1 comprising a density of at least 95% of theoretical density.

13. The sintered Ni—Ti-RE alloy of claim 12 wherein the density is least 98% of theoretical density.

14. The sintered Ni—Ti-RE alloy of claim 12 wherein the density is from 95% to 98% of theoretical density.

15. The sintered Ni—Ti-RE alloy of claim 1 exhibiting a hardness from 180 VHN to 550 VHN.

16. The sintered Ni—Ti-RE alloy of claim 1 , wherein the matrix does not include a brittle network of the second phase.

17. The sintered Ni—Ti-RE alloy of claim 1 including a lower oxygen content and carbon content than starting powders due to purification during sintering.

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