Titanium aluminide intermetallic alloys with improved wear resistance

• US 8,771,439 B2
• Filed: 04/01/2009
• Issued: 07/08/2014
• Est. Priority Date: 04/01/2009
• Status: Active Grant

• Current Assignee: UT-Battelle LLC
• Original Assignee: UT-Battelle LLC
• Inventors: Qu, Jun, Lin, Hua-Tay, Blau, Peter J., Sikka, Vinod K.
• Primary Examiner(s): ZHENG, LOIS L
• Application Number:
  US12/416,323
• Publication Number:
  US 20100252146A1
• Time in Patent Office: 1,924 Days
• Field of Search: 148/281, 148276-277, 148/284, 148668-671, 420/417, 420/418
• US Class Current: 148/284
• CPC Class Codes: C22C 14/00 Alloys based on titanium
• CPC Class Codes: C22C 30/00 Alloys containing less than 50% by weight of each constituent
• CPC Class Codes: C23C 8/10 Oxidising
• CPC Class Codes: C23C 8/80 After-treatment

Abstract

The invention is directed to a method for producing a titanium aluminide intermetallic alloy composition having an improved wear resistance, the method comprising heating a titanium aluminide intermetallic alloy material in an oxygen-containing environment at a temperature and for a time sufficient to produce a top oxide layer and underlying oxygen-diffused layer, followed by removal of the top oxide layer such that the oxygen-diffused layer is exposed. The invention is also directed to the resulting oxygen-diffused titanium aluminide intermetallic alloy, as well as mechanical components or devices containing the improved alloy composition.

Claims

1. A method for producing a wear-resistant titanium aluminide intermetallic alloy, the method comprising heating a titanium aluminide intermetallic alloy in an oxygen-containing environment at a temperature of at least 950°

C. for a processing time of at least about 1 hour to produce a top oxide layer and underlying oxygen -diffused layer, followed by removal of the entire top oxide layer such that the oxygen-diffused layer is exposed.

2. The method of claim 1, wherein said titanium aluminide intermetallic alloy is selected from the group consisting of Ti₃Al, TiAl, and TiAl₃.

3. The method of claim 1, wherein said temperature is at least 1000°

C.

4. The method of claim 1, wherein said oxygen-diffused layer has a thickness of 1-300 microns.

5. The method of claim 1, wherein said oxygen-diffused layer has a thickness of 1-100 microns.

6. The method of claim 1, wherein said oxygen-diffused layer has a thickness of 1-50 microns.

7. The method of claim 1, wherein said top oxide layer is removed by abrasion.

8. The method of claim 1, further comprising shaping said wear-resistant titanium aluminide intermetallic alloy into a mechanical component.

9. The method of claim 1, wherein said titanium aluminide intermetallic alloy is in the shape of a mechanical component.

10. The method of claim 8 or 9, wherein said mechanical component is a bearing.

11. The method of claim 10, wherein said bearing is a slide bearing.

12. The method of claim 8 or 9, wherein said mechanical component is a component normally subjected to elevated temperatures and required to be heat resistant.

13. The method of claim 12, wherein said mechanical component is selected from the group consisting of a turbine fan, compressor blade, a part of a thermal protection system, an exhaust engine valve, piston, and a turbocharger.

14. The method of claim 1, wherein said wear-resistant titanium aluminide intermetallic alloy has a microindentation Knoop'"'"'s hardness of at least 6.0 GPa.

15. The method of claim 1, wherein said wear-resistant titanium aluminide intermetallic alloy has a microindentation Knoop'"'"'s hardness of at least 7.0 GPa.

16. The method of claim 1, wherein said wear-resistant titanium aluminide intermetallic alloy possesses a wear rate that is at least 10 times less, under substantially identical testing conditions, compared to the wear rate of a titanium aluminide intermetallic alloy of same composition but not possessing said exposed oxygen-diffused layer.

17. The method of claim 1, wherein said wear-resistant titanium aluminide intermetallic alloy possesses a steady-state friction coefficient that is at least 10% reduced, under substantially identical testing conditions, compared to the steady-state friction coefficient of a titanium aluminide intermetallic alloy of same composition but not possessing said exposed oxygen -diffused layer.

18. The method of claim 1, wherein said temperature is at least 1050°

C.

19. The method of claim 1, wherein said temperature is about 1100°

C.

20. The method of claim 1, wherein said temperature is up to about 1100°

C.