Medical alloys with a non-alloyed dispersion and methods of making same

• US 20070131318A1
• Filed: 11/09/2006
• Published: 06/14/2007
• Est. Priority Date: 12/12/2005
• Status: Abandoned Application

• Current Assignee: Accellent Incorporated (Integer Holdings Corporation Inc)
• Original Assignee: Accellent Incorporated (Integer Holdings Corporation Inc)
• Inventors: Broadley, Mark, Farina, Jeffrey, Younker, Christopher
• Application Number:
  US11/595,034
• Publication Number:
  US 20070131318A1
• Time in Patent Office: Days
• US Class Current: 148/556
• CPC Class Codes: C22F 1/10 of nickel or cobalt or alloys based thereon

Abstract

An article made of a medical alloy having two or more alloying elements, and a uniform dispersion of discrete particles, which are substantially free of the two or more alloying elements. A method of making the article includes melting a composition having two or more alloying elements to form an alloy and dispersing a discrete particle in the alloy to form an ingot. The melting and dispersing are performed at a temperature above the alloying temperature of the composition and below the melting temperature of the discrete particle. The ingot is hot worked to form a processed ingot. The processed ingot is cold worked and annealed to form the article.

Claims

1. An article comprising:

a medical alloy comprising at least two alloying elements; and

a uniform dispersion of discrete particles in the article, wherein the discrete particles are substantially free of the at least two alloying elements.

2. An article according to claim 1, wherein the medical alloy comprises a nickel-titanium alloy.

3. An article according to claim 2, wherein the nickel-titanium alloy is nitinol.

4. An article according to claim 1, wherein the discrete particles are selected from the group consisting of iridium, platinum, gold, rhenium, tungsten, palladium, rhodium, tantalum, silver, ruthenium, and hafnium.

5. An article according to claim 1, wherein the discrete particles comprise at least one element substantially free of the at least two alloying elements.

6. An article according to claim 5, wherein the at least one element comprises at least one of iridium, platinum, gold, rhenium, tungsten, palladium, rhodium, tantalum, silver, ruthenium, and hafnium.

7. An article according to claim 1, wherein the discrete particles comprise at least one alloy substantially free of the at least two alloying elements.

8. An article according to claim 7, wherein the at least one alloy comprises at least two of iridium, platinum, gold, rhenium, tungsten, palladium, rhodium, tantalum, silver, ruthenium, and hafnium.

9. An article according to claim 1, wherein the discrete particles are aligned perpendicular to the likely direction of fatigue crack propagation.

10. An article according to claim 1, wherein the medical alloy comprises a binary alloy.

11. An article according to claim 1, wherein the medical alloy comprises a ternary or higher alloy.

12. An article according to claim 1, wherein the article is an implantable medical component or device.

13. A method of making an article, the method comprising:

melting a composition comprising at least two alloying elements to form an alloy and dispersing at least one type of discrete particle in the alloy to form a cast ingot, wherein the melting and dispersing are performed at a temperature above the alloying temperature of the composition and below the melting temperature of the discrete particles;

hot working the cast ingot to form a processed ingot; and

cold working and annealing the processed ingot to form the article.

14. A method according to claim 13, wherein the composition comprises a substantially equiatomic amount of nickel and titanium.

15. A method of making an article, the method comprising:

vacuum melting a composition comprising at least two alloying elements to form a cast ingot, wherein the melting is performed at or above an alloying temperature for the composition;

pour stream injecting particles into the cast ingot during vacuum induction melting at a temperature below the melting point of the particles;

hot working the cast ingot to form a processed ingot; and

cold working and annealing the processed ingot to form the article, the article comprising a medical alloy comprising at least two alloying elements and a uniform dispersion of discrete particles substantially free of the at least two alloying elements.

16. A method according to claim 15, wherein the composition comprises a substantially equiatomic amount of nickel and titanium and the article comprises a nickel titanium alloy and a uniform dispersion of discrete particles substantially free of nickel and titanium.

17. A method according to claim 16, wherein the composition has a nickel:

titanium atomic ratio of about 50;

50.

18. A method according to claim 15 wherein the particles are selected from the group consisting of iridium, platinum, gold, rhenium, tungsten, palladium, rhodium, tantalum, silver, ruthenium, and hafnium.

19. A method according to claim 15, wherein the particles comprise an alloy comprising at least one of iridium, platinum, gold, rhenium, tungsten, palladium, rhodium, tantalum, silver, ruthenium, and hafnium.

20. A method according to claim 15, wherein the vacuum melting comprises vacuum induction melting.

21. A method according to claim 15, wherein the vacuum melting comprises vacuum skull melting.

22. A method of making an article, the method comprising:

preparing an electrode having a hollow center, the electrode comprising a composition comprising at least two alloying elements;

introducing particles into the hollow center;

vacuum arc melting the electrode and the particles at a temperature above the alloying temperature of the composition and below the melting point of the particles to form a cast ingot;

hot working the cast ingot to form a processed ingot; and

cold working and annealing the processed ingot to form the article, the article comprising a nickel-titanium alloy and a uniform dispersion of discrete particles substantially free of the at least two alloying elements.

23. A method according to claim 22, wherein the composition comprises a substantially equiatomic amount of nickel and titanium.

24. A method according to claim 22, wherein the particles are selected from the group consisting of iridium, platinum, gold, rhenium, tungsten, palladium, rhodium, tantalum, silver, ruthenium, and hafnium.

25. A method according to claim 22, wherein the particles comprise an alloy comprising at least one of iridium, platinum, gold, rhenium, tungsten, palladium, rhodium, tantalum, silver, ruthenium, and hafnium.

26. A method according to claim 22, wherein the particles are introduced by injecting the particle into the hollow center.

27. A method according to claim 22, wherein the particles are introduced by packing a powdered particle into the hollow center.