Excellent dynamic mechanical properties of a newly developed titanium alloy with bimodal structure

Abstract

In this work, a new dual-phase Ti-6Al-2Zr-2Mo-2 Nb-2Sn-1 V alloy was designed based on the classical Al-equivalent and Mo-equivalent design criteria, combined with the role of alloying elements in titanium alloys. The microstructure, microtexture and dynamic compressive properties of the alloy were studied systematically. A bimodal microstructure with 85 vol% α and 15 vol% β phase was obtained after annealing treatment. The equiaxed α phase (αp) and β phase conforms to Burgers orientation relationship (BOR), and part of lamellar α (αs) had similar orientations to the surrounding αp grains, resulting in the overlap of αp and αs texture components. The newly developed titanium alloy exhibited excellent dynamic compressive strength-plasticity-impact absorption energy matching, attributed to the coordinated deformation between α and β phases as well as αp and transformed β microstructure. The flow stress, plastic strain and impact energy at the critical failure strain rate of 4000 s−1 were 1586 MPa, 0.31 and 490 J/cm3, respectively. The dynamic mechanical properties of the new alloy are superior to those of typical titanium alloys and have the potential to be applied in high-strain rate environments.