BCC MATERIALS OF TITANIUM, ALUMINUM, VANADIUM, AND IRON, AND PRODUCTS MADE THEREFROM

Abstract

New beta-style (bcc) titanium alloys are disclosed. The new alloys generally include 2.0-6.0 wt. % Al, 4.0-12.0 wt. % V, and 1.0-5.0 wt. % Fe, the balance being titanium, any optional incidental elements, and unavoidable impurities. The new alloys may realize an improved combination of properties as compared to conventional titanium alloys.

Claims

1. A titanium alloy comprising: 2.0-6.0 wt. % Al; 4-12 wt. % V; and 1.0-5.0 wt. % Fe; the balance being Ti, optional incidental elements, and unavoidable impurities.

2. The titanium alloy of claim 1, wherein the titanium alloy includes a sufficient amount of the Ti, the Al, the V, and the Fe to realize a beta transus temperature of not greater than 850° C.

3. The titanium alloy of claim 1, wherein the alloy includes at least 1.5 wt. % Fe.

4. The titanium alloy of any of the preceding claims, wherein the alloy includes at least 2.5 wt. % Fe.

5. The titanium alloy of claim 3, wherein the alloy includes not greater than 4.25 wt. % Fe.

6. The titanium alloy of claim 4, wherein the alloy includes not greater than 3.5 wt. % Fe.

7. The titanium alloy of claim 1, wherein the alloy includes at least 2.5 wt. % Al.

8. The titanium alloy of claim 1, wherein the alloy includes at least 3.0 wt. % Al.

9. The titanium alloy of claim 7, wherein the alloy includes not greater than 5.5 wt. % Al.

10. The titanium alloy of claim 8, wherein the alloy includes not greater than 5.0 wt. % Al.

11. The titanium alloy of claim 1, wherein the alloy includes at least 6.0 wt. % V.

12. The titanium alloy of claim 1, wherein the alloy includes at least 7.5 wt. % V.

13. The titanium alloy of claim 11, wherein the alloy includes not greater than 10.0 wt. % V.

14. The titanium alloy of claim 12, wherein the alloy includes not greater than 8.5 wt. % V.

15. The titanium alloy of claim 1, wherein the titanium alloy is a titanium alloy body.

16. The titanium alloy body of claim 15, wherein the titanium alloy body is one of an ingot, a rolled product, an extrusion, a forging, a shape casting, or an additively manufactured product.

17. A method comprising: (i) using a feedstock in an additive manufacturing apparatus, wherein the feedstock comprises: 2.0-6.0 wt. % Al; 4-12 wt. % V; and 1.0-5.0 wt. % Fe; the balance being Ti, optional incidental elements, and unavoidable impurities; (ii) producing a metal product in the additive manufacturing apparatus using the feedstock.

18. The method of claim 17, wherein the feedstock comprises a powder feedstock, wherein the method comprises: (a) dispersing a metal powder of the powder feedstock in a bed and/or spraying a metal powder of the powder feedstock towards or on a substrate; (b) selectively heating a portion of the metal powder above its liquidus temperature, thereby forming a molten pool; (c) cooling the molten pool, thereby forming a portion of the metal product, wherein the cooling comprises cooling at a cooling rate of at least 100° C. per second; and (d) repeating steps (a)-(c) until the metal product is completed.

19. The method of claim 17, wherein the feedstock comprises a wire feedstock, wherein the method comprises: (a) using a radiation source to heat the wire feedstock above its liquidus point, thereby creating a molten pool; (b) cooling the molten pool at a cooling rate of at least 1000° C. per second; and (c) repeating steps (a)-(b) until the metal product is completed.

20. The method of claim 17, comprising cooling at a rate sufficient to form at least one precipitate phase, wherein the at least one precipitate phase comprises Ti.sub.3Al.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0048] FIG. 1 is a schematic illustration of bcc, fcc, and hcp unit cells.

[0049] FIG. 2a is a graph of the Scheil model solidification path of Ti-4Al-8V-3Fe and Ti-1Al-8V-5Fe alloys.

[0050] FIG. 2b is a graph showing the effect of iron content on the freezing range of a Ti-4Al-8V-XFe alloy.

[0051] FIG. 2c is a graph showing the effect of iron content on the equilibrium phase fields of a Ti-4Al-8V-XFe alloy in the solid state.

[0052] FIG. 2d is a graph showing the effect of aluminum content on the equilibrium freezing range of a Ti-8V-3Fe-XAl alloy.

[0053] FIG. 2e is a graph of the effect of aluminum content on the equilibrium phase fields of a Ti-8V-3Fe-XAl alloy in the solid state.

[0054] FIG. 2f is a graph of the effect of vanadium content on the equilibrium freezing range of a Ti-4Al-3Fe-XV alloy.

[0055] FIG. 2g is a graph showing the effect of vanadium content on the equilibrium phase fields of a Ti-4Al-3Fe-XV alloy.

[0056] FIG. 3 is a flow chart of one embodiment of a method to produce a new material.

[0057] FIG. 4 is a flow chart of one embodiment of a method to obtain a wrought product having a bcc solid solution structure with one of more of the precipitates therein.

DETAILED DESCRIPTION

Example 1

[0058] A Ti-4Al-8V-3Fe and a conventional Ti-6Al-4V alloy were cast via arc melt casting into rods. After casting, mechanical properties of the as-cast alloys were measured in accordance with ASTM E8, the results of which are shown in Tables 3-4. Specimens of the heat treated Ti-4Al-8V-3Fe alloy were solution heat treated at 760° C. for 0.5 hours, then water quenched, then heat treated at 515° C. for 2 hours, and then air cooled. The mechanical properties of the heat treated alloys were then tested in accordance with ASTM E8, the results of which are shown in Table 4, below. All reported strength and elongation properties were from testing in the longitudinal (L) direction.

TABLE-US-00004 TABLE 4 Conventional Ti—6Al—4V Properties Condition TYS (MPa) UTS (MPa) % EL As-Cast 715 881 11

TABLE-US-00005 TABLE 5 Ti—4Al—8V—3Fe Properties Condition TYS (MPa) UTS (MPa) % EL As-Cast 816 877 2 Heat Treated 1273 1301 3

[0059] As shown in Tables 4-5, the tensile yield strength of the Ti-4Al-8V-3Fe alloy is improved over the Ti-6Al-4V alloy when tested at room temperature, without a corresponding reduction in ultimate tensile strength.

[0060] While various embodiments of the new technology described herein have been described in detail, it is apparent that modifications and adaptations of those embodiments will occur to those skilled in the art. However, it is to be expressly understood that such modifications and adaptations are within the spirit and scope of the presently disclosed technology.