Achieving high-temperature strength and plasticity in near-α Ti-7Al-3Zr-2V alloy using cluster formula design

Abstract

We here report a Ti-7Al-3Zr-2V alloy, designed following cluster formula approach and prepared by laser additive manufacturing, whose mechanical performance is superior to commonly used Ti-6Al-4V alloy both at as-deposited state and at 600 °C. Its composition formula α-{[Al-Ti12](AlTi2)}15+β-{[Al-Ti12Zr2](V3)}2 features an enhanced α unit proportion of 15/17 (with respect to 12/17 of Ti-6Al-4V) and stabilized β-Ti via Zr and V alloying. This alloy shows a good laser-additive-manufacturing processibility. At the as-deposited state, its ultimate tensile strength of 1060 MPa, yield strength of 976 MPa, and particularly elongation of 14.9% are all better than those of Ti-6Al-4V. At 600 °C, its ultimate tensile strength of 545 MPa, yield strength of 497 MPa, and elongation of 39.7% far exceed the performance of Ti-6Al-4V. After the tensile tests at 600 °C, the α plate size and its volume fraction remain basically unchanged, in sharp contrast to Ti-6Al-4V.