MICROSTRUCTURES AND MECHANICAL PROPERTIES OF BETA TITANIUM ALLOYS.

Abstract

Beta titanium alloys have been developed as candidates for new aerospace materials because of their good combination of high strength, high fracture toughness and their good workability. In this paper, the general features of beta titanium alloys are summarized and compared with conventional alpha or alpha-beta titanium alloys. The mechanical properties of Ti-10V-2Fe-3Al alloy and Ti-15V-3Al-3Sn-3Cr alloy, which are the most promising beta titanium alloys, are introduced in relation to their microstructural change after aging heat treatments. High tensile strengths about 140 kgf/mm**2 can be attained through the control of the morphology and the distribution of precipitated alpha particles by aging heat treatment in both of these alloys. Ti-10V-2Fe-3Al alloy after aging heat treatment shows 68 kgf/mm**2 in fatigue strength, and has a higher fracture toughness than Ti-6Al-4V alloy, which has the same levels of 0. 2% proof stresses.