Powder metallurgy titanium alloys

Patent metadata

Field	Value
Publication number	US-11008639-B2
Application number	US-201515759713-A
Country	US
Kind code	B2
Filing date	Sep 16, 2015
Priority date	Sep 16, 2015
Publication date	May 18, 2021
Grant date	May 18, 2021

Abstract

A sintered Ti alloy comprising: 4 to 6 wt. % iron; 1 to 4 wt. % aluminium or 1 to 3 wt. % copper; >0 to 0.5 wt. % silicon; >0 to 0.3 wt. % boron; >0 to 1 wt. % lanthanum, and the balance being titanium with incidental impurities. In the associated powder metallurgy formation process, the boron and lanthanum content is preferably introduced into a blended powder mixture in the form of lanthanum boride (LaB6).

First claim

The invention claimed is:

1. A sintered Ti alloy consisting of:
4 to 6 wt. % iron;
1 to 4 wt. % aluminium or 1 to 3 wt. % copper;
>0 to 0.25 wt. % silicon;
>0 to 0.3 wt. % boron;
>0 to 1 wt. % lanthanum, and
the balance being titanium with incidental impurities,
wherein the sintered Ti alloy has an ultimate tensile strength of at least 900 MPa, a yield strength of at least 800 MPa, and an elongation percentage of at least 6%.

2. The sintered Ti alloy according to claim 1 , wherein the sintered Ti alloy consists of 4 to 6 wt. % iron; 1 to 4 wt. % aluminium or 1 to 3 wt. % copper; 0.05 to 0.25 wt. % silicon; 0.05 to 0.3 wt. % boron; 0.1 to 1 wt. % lanthanum, and the balance titanium with incidental impurities.

3. The sintered Ti alloy according to claim 1 , wherein the sintered Ti alloy consists of 4 to 6 wt. % iron; 2 to 4 wt. % aluminium or 2 to 3 wt. % copper; 0.1 to 0.25 wt. % silicon; 0.09 to 0.21 wt. % boron; 0.2 to 0.49 wt. % lanthanum, and the balance titanium with incidental impurities.

4. The sintered Ti alloy according to claim 1 , wherein the sintered Ti alloy consists of 4 to 6 wt. % iron, 1 to 4 wt. % aluminium, 0.1 to 0.25 wt. % silicon, 0.09 to 0.21 wt. % boron, 0.2 to 0.49 wt. % lanthanum, and the balance titanium with incidental impurities, and wherein the sintered Ti has an ultimate tensile strength of at least 950 MPa, yield strength of at least 830 MPa and elongation percentage of at least 7%.

5. The sintered Ti alloy according to claim 1 , wherein the sintered Ti alloy consists of 4 to 6 wt. % iron, 1 to 3 wt. % copper, 0.1 to 0.25 wt. % silicon, 0.09 to 0.21 wt. % boron, 0.2 to 0.49 wt. % lanthanum, and the balance titanium with incidental impurities, and wherein the sintered Ti has an ultimate tensile strength of at least 1000 MPa, yield strength of at least 830 MPa and elongation percentage of at least 8%.

6. The sintered Ti alloy according to claim 1 , wherein the sintered Ti alloy is selected from the group consisting of: Ti-4Fe-2.5Al-0.1Si-0.3LaB 6 , Ti-5Fe-2.5Al-0.1Si-0.3LaB 6 , Ti-5Fe-2.5Al-0.1Si-0.5LaB 6 , Ti-5.5Fe-2.5Cu-0.1Si-0.3LaB 6 , Ti-5.5Fe-2.5Cu-0.1Si-0.5LaB 6 , Ti-5.5Fe-2.5Al-0.1Si-0.3LaB 6 , and Ti-5.5Fe-2.5Al-0.1Si-0.5LaB 6 .

7. The sintered Ti alloy according to claim 1 , wherein the sintered Ti alloy has a microstructure comprising α-Ti, β-Ti, TiB, La 2 O 3 and LaCl x O y phases.

8. An article manufactured from the sintered titanium Ti alloy according to claim 1 .

9. A sintered alloy article, formed from a process comprising the steps of:
forming a blended powder mixture comprising mixing titanium powder, elemental aluminium or copper powder, iron powder, silicon powder and LaB 6 powder to provide an alloy blend consisting of:
4 to 6 wt. % iron;
1 to 4 wt. % aluminium or 1 to 3 wt. % copper;
>0 to 0.25 wt. % silicon;
>0 to 0.3 wt. % boron;
>0 to 1 wt. % lanthanum, and
the balance being titanium with incidental impurities;
consolidating the blended powder mixture by compacting the powder mixes using a powder consolidation method at a pressure in the range from 100 to 1100 MPa to provide a green compact;
heating the Ti green compact either in a protective atmosphere or under vacuum to a temperature over 1000° C. and holding the green compact at this temperature for at least 30 minutes, thereby sintering titanium to form a sintered compact; and
cooling the sintered compact to form a sintered alloy article, wherein the sintered alloy has an ultimate tensile strength of at least 900 MPa, a yield strength of at least 800 MPa, and an elongation percentage of at least 6%.

10. A process of producing a sintered Ti alloy article comprising:
forming a blended powder mixture comprising mixing titanium powder, elemental aluminum or copper powder, iron powder, silicon powder and LaB 6 powder to provide an alloy blend consisting of:
4 to 6 wt. % iron;
1 to 4 wt. % aluminium or 1 to 3 wt. % copper;
>0 to 0.25 wt. % silicon;
>0 to 0.3 wt. % boron;
>0 to 1 wt. % lanthanum, and
the balance being titanium with incidental impurities;
consolidating the blended powder mixture by compacting the powder mixture using a powder consolidation method at a pressure in the range from 100 to 1100 MPa to provide a green compact;
heating the green compact either in a protective atmosphere or under vacuum to a temperature over 1000° C. and holding the green compact at this temperature for at least 30 minutes, thereby sintering titanium to form a sintered compact; and
cooling the sintered compact to form a sintered alloy article, wherein the sintered Ti alloy article has an ultimate tensile strength of at least 900 MPa, a yield strength of at least 800 MPa, and an elongation percentage of at least 6%.

11. The process according to claim 10 , wherein the powder consolidation method comprises a room temperature consolidation method selected from die pressing, direct powder rolling, cold isostatic pressing, impulse pressing, or combination thereof.

12. The process according to claim 10 , further comprising the step after consolidating the powder blend of:
heating the green compact to a temperature ranging from 100° C. to 250° C. to release absorbed water from the titanium powder prior to sintering.

13. The process according to claim 10 , wherein titanium powder of the blended powder mixture comprises hydrogenated-dehydrogenated titanium powder or hydrogenated titanium powder.

14. The process according to claim 13 , wherein titanium powder of the blended powder mixture comprises hydrogenated titanium powder and the method further includes the step of:
refining said green compact by heating to 300 to 900° C. and holding the green compact at such temperatures for at least 30 minutes.

15. The process according to claim 10 , wherein the titanium powder is −100 to −500 mesh and at least 99 wt. % purity.

16. The process according to claim 10 , wherein each of the elemental aluminum powder, copper powder, iron powder, silicon powder and LaB 6 powder is −325 mesh and at least 99 wt. % purity.

17. The process according to claim 10 , wherein the elemental silicon and boron powders are either:
Premixed together prior to introduction into the blended powder; or
introduced simultaneously into blended powder mixture.

18. The process according to claim 10 , wherein the consolidation step pressure is from 200 to 800 MPa.

19. The process according to claim 10 , wherein the sintering temperature is from 1000° C. to 1400° C.

20. The process according to claim 10 , wherein the sintered alloy article has a sintered density of at least 95% of theoretical density.

Assignees

• Baoshan Iron & Steel

Inventors

• Yang Yafeng
• Qian Ma
• Luo Shudong
• Sun Jifeng
• Huang Aijun

Classifications

• C22C1/0458

  Alloys based on titanium, zirconium or hafnium · CPC title

• B22F2999/00

  Aspects linked to processes or compositions used in powder metallurgy · CPC title

• C22C14/00 Primary

  Alloys based on titanium · CPC title

• B22F2998/10

  Processes characterised by the sequence of their steps · CPC title

• B22F3/16

  in successive or repeated steps · CPC title