The microstructure and tensile properties of additively manufactured Ti–6Al–2Zr–1Mo–1V with a trimodal microstructure obtained by multiple annealing heat treatment

Abstract

Unlike acicular martensite, combining a lamellar and equiaxed α microstructure is known to impart high ductility for Ti-6.5Al–2Zr–1Mo–1V (TA15). In this article, we report innovative heat treatment aimed at optimizing the mechanical properties of additively manufactured TA15. After the proposed heat treatment, a trimodal microstructure consisting of equiaxed α, lamellar α, and a transformed β matrix was obtained. The resulting tensile properties were equivalent to those of forged TA15 counterparts. This paper discusses in detail the microstructure evolution involved in the heat treatment, as well as the microstructure–mechanical property relationships. The exceptional combination of strength and ductility obtained after the proposed heat treatment can allow the full exploitation of the additive manufacturing advantages of this excellent material.