High-temperature TiAl alloy

Patent metadata

Field	Value
Publication number	US-10060012-B2
Application number	US-201514612504-A
Country	US
Kind code	B2
Filing date	Feb 3, 2015
Priority date	Feb 6, 2014
Publication date	Aug 28, 2018
Grant date	Aug 28, 2018

Abstract

The present invention relates to a TiAl alloy for use at high temperatures having the main constituents titanium and aluminum and having a proportion of aluminum of greater than or equal to 30 at. % and a matrix composed of β phase and precipitates of ω phase embedded in the matrix, with the β phase and the ω phase together making up at least 55% by volume of the microstructure, and also a process for the production thereof and the use thereof.

First claim

What is claimed is:

1. A TiAl alloy for use at high temperatures, wherein the alloy comprises:
from 30 to 42 at. % of Al
from 5 to 25 at. % of Nb
from 2 to 10 at. % of Mo
from 0.1 to 10 at. % of Co
from 0.1 to 0.5 at. % of Si
from 0.1 to 0.5 at. % of Hf,

balance Ti,
and wherein the alloy comprises a matrix of β phase and precipitates of ω phase embedded in the matrix, the β phase and the ω phase together making up at least 55% by volume of a microstructure of the alloy.

2. The TiAl alloy of claim 1 , wherein the β phase and the ω phase together make up at least 75% by volume of the microstructure.

3. The TiAl alloy of claim 1 , wherein the β phase and the ω phase are present in the microstructure in a volume ratio of greater than 1:4 and less than 4:1, relative to one another.

4. The TiAl alloy of claim 1 , wherein the ω phase is present with grain sizes ranging from 5 nm to 500 nm.

5. The TiAl alloy of claim 1 , wherein the ω phase is present in the microstructure with grain sizes in at least two different grain size ranges, a first grain size range encompassing grain sizes from 5 nm to 100 nm and a second grain size range encompassing grain sizes from 200 nm to 500 nm.

6. The TiAl alloy of claim 1 , wherein the β matrix has a network-like microstructure.

7. The TiAl alloy of claim 1 , wherein the alloy comprises:
from 30 to 35 at. % of Al
from 15 to 25 at. % of Nb
from 5 to 10 at. % of Mo
from 5 to 10 at. % of Co
from 0.1 to 0.5 at. % of Si
from 0.1 to 0.5 at. % of Hf,

balance Ti.

8. A process for producing the TiAl alloy of claim 1 , wherein the process comprises producing the alloy pyrometallurgically and drawing it as a single crystal or casting it to form a polycrystalline product or comprises producing the alloy at least partly powder-metallurgically.

9. A component of a flow machine, wherein the component comprises the alloy of claim 1 .

10. A TiAl alloy for use at high temperatures, wherein the alloy comprises titanium and aluminum as main constituents, a proportion of aluminum being greater than or equal to 30 at. %, and additionally comprises Nb and Mo in proportions in at. % of from 2:1 to 3:1, and wherein the alloy comprises a matrix of β phase and precipitates of w phase embedded in the matrix, the β phase and the ω phase together making up at least 55% by volume of a microstructure of the alloy.

11. The TiAl alloy of claim 10 , wherein the β phase and the ω phase together make up at least 75% by volume of the microstructure.

12. The TiAl alloy of claim 10 , wherein the β phase and the ω phase are present in the microstructure in a volume ratio of greater than 1:4 and less than 4:1, relative to one another.

13. The TiAl alloy of claim 10 , wherein the ω phase is present with grain sizes ranging from 5 nm to 500 nm.

14. The TiAl alloy of claim 10 , wherein the ω phase is present in the microstructure with grain sizes in at least two different grain size ranges, a first grain size range encompassing grain sizes from 5 nm to 100 nm and a second grain size range encompassing grain sizes from 200 nm to 500 nm.

15. The TiAl alloy of claim 10 , wherein the β matrix has a network-like microstructure.

16. The TiAl alloy of claim 10 , wherein the alloy further comprises at least one element selected from W, V, and Co.

17. The TiAl alloy of claim 10 , wherein the alloy further comprises at least one element selected from Zr, Y, and Hf.

18. The TiAl alloy of claim 10 , wherein the alloy comprises:
from 30 to 42 at. % of Al
from 5 to 25 at. % of Nb
from 2 to 10 at. % of Mo
from 0.1 to 10 at. % of Co
from 0.1 to 0.5 at. % of Si
from 0.1 to 0.5 at. % of Hf,

balance Ti.

19. A process for producing the TiAl alloy of claim 10 , wherein the process comprises producing the alloy pyrometallurgically and drawing it as a single crystal or casting it to form a polycrystalline product or comprises producing the alloy at least partly powder-metallurgically.

20. A component of a flow machine, wherein the component comprises the alloy of claim 10 .

Assignees

• MTU Aero Engines AG

Inventors

• Schloffer Martin

Classifications

• C22C27/02

  Alloys based on vanadium, niobium, or tantalum · CPC title

• C22C14/00 Primary

  Alloys based on titanium · CPC title

• C22C30/00

  Alloys containing less than 50% by weight of each constituent · CPC title

• C22C1/00

  Making non-ferrous alloys (by electrothermic methods C22B4/00; by electrolysis C25C1/24, C25C3/36) · CPC title

• B22D21/022

  Casting heavy metals, with exceedingly high melting points, i.e. more than 1600 degrees C, e.g. W 3380 degrees C, Ta 3000 degrees C, Mo 2620 degrees C, Zr 1860 degrees C, Cr 1765 degrees C, V 1715 degrees C · CPC title