Alpha plus beta type titanium alloy

Abstract

A (α+β) type Ti alloy contains 7 wt % to 8.5 wt % of Al, 0.5 wt % to 1.5 wt % of V, 1 wt % to 3 wt % of Mo, 1 wt % to 3 wt % Cr, 0.3 wt % to 1 wt % of Fe, 0.05 wt % to 0.1 wt % of rare earth element, Ti, and unavoidable impurities. The Ti alloy can be produced by varmelting, forging, rolling and casting pressure processing or powder metallurgy. The total amount of impurities of C, H, O, and N is not higher than 0.25 wt %. V, Mo, and rare earth elements are added in forms of Al—V intermediate alloy, Al—Mo intermediate alloy, and La—Ce mixed rare earth, respectively. The room-temperature tensile strength and yield strength of the Ti alloy are higher than those of Ti—6Al—4V by more than 30%, the high-temperature strength is superior to that of Ti—6Al—4V, density and cost are lower than those of Ti—6Al—4V.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of Invention[0002]The present invention relates to a titanium (Ti) alloy, and more particularly to a high-strength cost-effective Alpha plus Beta (α+β) type Ti alloy.[0003]2. Related Art[0004](α+β) type Ti alloys are widely applied in the fields such as aviation, aerospace, automobile, golf club head, and bicycle, in which Ti—6Al—4V alloy successfully developed by U.S.A. in 1954 is a typical representative. Ti—6Al—4V alloy has preferable comprehensive performance, and present usage of Ti—6Al—4V alloy has been over a half of all Ti alloys. However, the performance-to-price ratio of the Ti—6Al—4V alloy is not high enough, long-term working temperature is around 350° C., vanadium (V) of high content in the alloy makes the price of the alloy relatively high, and the room-temperature strength and high-temperature strength still have room to improve, which limit the further application of Ti—6Al—4V alloy in national defense and military industry a...

AI Technical Summary

Benefits of technology

[0008]The Ti alloy of the present invention can be produced by general methods of preparing Ti alloy, such as varmelting, forging, rolling, and casting processing or powder metallurgy. The total amount of impurities of C, H, O, and N is controlled to be not higher than 0.25 wt %. V is added in form of Al—V intermediate alloy, and Mo is added in form of Al—Mo intermediate alloy, so as to ensure the accuracy and uniformity of the ingredients of the alloy, thereby ensuring the consistency of the performance of the alloy material. The rare earth elements are added in form of La—Ce mixed rare earth.

[0009]The Al content of the (α+β) type Ti alloy of the present invention is higher than that of Ti—6Al—4V, and the increase of the Al content has significant effect in improving the room-temperature strength and high-temperature strength, reducing the specific gravity, and increasing the elastic modulus. V, Mo, Cr, and Fe are β stabilizing elements. Compared with Ti—6Al—4V, the addition of V is significantly reduced, thus reducing the production cost of the Ti alloy. The addition of proper amount of rare-earth elements improves the antioxidant performance of the Ti alloy surface. The room-temperature tensile strength and yield strength of the (α+β) Ti alloy of the present invention is improved by more than 30% compared with Ti—6 Al—4V, high-temperature strength is significantly superior to Ti—6 Al—4V, density and cost are a little lower than those of Ti—6 Al—4V. Therefore, the Ti alloy of the present invention has higher performance-to-price ratio than that of Ti—6 Al—4V, and has broad market prospects.

Problems solved by technology

However, the performance-to-price ratio of the Ti—6Al—4V alloy is not high enough, long-term working temperature is around 350° C., vanadium (V) of high content in the alloy makes the price of the alloy relatively high, and the room-temperature strength and high-temperature strength still have room to improve, which limit the further application of Ti—6Al—4V alloy in national defense and military industry and civilian products.