Ti–6Al–4V alloy with an ultrafine-grained microstructure exhibiting low-temperature–high-strain-rate superplasticity

Abstract Superplasticity in microcrystalline Ti–6Al–4V (mass%) alloys is exhibited under high temperatures more than 1123 K and low strain rates less than 10 −3 s −1 , thereby restricting their practical application to specialized areas such as aerospace. We herein identify a new type of Ti–6Al–4V alloy exhibiting low-temperature (below 973 K)–high-strain-rate (10 −2 s −1 ) superplasticity. The ultrafine-grained Ti–6Al–4V alloy was produced by simple hot orking of an α′-martensite microstructure alloy, and it has a great potential for application as cost-affordable superplastic Ti alloy.