Method for manufacturing a titanium alloy for biomedical devices

Patent metadata

Field	Value
Publication number	US-9677162-B2
Application number	US-201214357559-A
Country	US
Kind code	B2
Filing date	Nov 7, 2012
Priority date	Nov 10, 2011
Publication date	Jun 13, 2017
Grant date	Jun 13, 2017

Abstract

The invention relates to a method for manufacturing a titanium alloy having superelastic properties and/or shape memory for biomedical use, which comprises the steps of: preparing an ingot by melting the various metals that form the desired alloy in a vacuum; optionally homogenizing the ingot in a vacuum by high-temperature annealing (higher than 900° C.); first quenching; mechanical shaping (rolling, drawing, machining or the like); heat treatment for redissolution in beta phase beyond the beta transus temperature (until a second temperature and then maintaining same for a certain time); and second quenching; characterized in that said heat treatment phase is carried out in a gaseous atmosphere and also constitutes a surface treatment suitable for forming on the surface a layer of nitride, carbonitride, oxide, oxynitride or the like.

First claim

What is claimed is:

1. A method for manufacturing a titanium alloy with no nickel and with superelastic and/or shape memory properties for biomedical applications, comprising the steps of:
preparing an ingot of the titanium alloy by vacuum melting the the titanium alloy;
performing a vacuum homogenization of the ingot by annealing the ingot at a first temperature, wherein the annealing comprises raising the temperature of the ingot and holding it at that temperature for a period that allows full homogenization;
performing a first quenching of the vacuum homogenized ingot;
performing a mechanical shaping of the ingot at an ambient temperature into a predetermined shape;
performing a heat treatment of the ingot for redissolution in a beta phase beyond the beta transus temperature, the heat treatment comprising raising the temperature up to a second required temperature and holding at that temperature for a certain period; and
performing a second quenching of the ingot;

wherein the method is characterized in that said heat treatment is carried out in a gaseous atmosphere and the heat treatment further comprises a nitriding phase wherein a surface treatment is applied to the ingot through a reaction with one or more gases in the gaseous atmosphere, so as to form a coat of nitride, carbonitride or oxynitride evenly on one or more surfaces of the ingot.

2. The method according to claim 1 , wherein the nitriding phase is carried out at a temperature ranging between 600° C. and 1050° C.

3. The method according to claim 2 , wherein the nitriding phase is carried out at a temperature ranging between 800° C. and 1050° C.

4. The method according to claim 1 wherein the duration of holding at the annealing temperature of the homogenization step ranges between 12 and 20 hours.

5. The method according to claim 4 , wherein the duration of holding at the annealing temperature of the homogenization step is about 16 hours.

6. The method according to claim 1 wherein the nitriding phase is carried out in a nitrogen atmosphere.

7. The method according to claim 1 wherein the nitriding phase is combined with a simultaneous phase of recrystallization.

8. The method according to claim 1 wherein the homogenization step is carried out at a temperature above 900° C.

9. The method according to claim 1 wherein the first and second quenches are carried out either with water or with air.

Assignees

• Inst Nat Des Sciences Appliquees De Rennes
• Centre Nat Rech Scient

Inventors

• Gloriant Thierry
• Gordin Doina

Classifications

• C22F1/183 Primary

  of titanium or alloys based thereon · CPC title

• A61L31/022

  Metals or alloys · CPC title

• A61L2400/16

  Materials with shape-memory or superelastic properties · CPC title

• C22C1/02

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

• F04C2270/0421

  Controlled or regulated · CPC title