Low Temperature Superplasticity of Ti-6AI-4V Processed by Warm Multidirectional Forging

摘要

Multidirectional forging has been developed to produce an ultrafine-grain (UFG) microstructure in the two-phase titanium alloy Ti-6A1-4V. A microstructure with a grain size of 135 nm was attained, enabling low-temperature superplasticity (LTSP) at 550°C. A total elongation of 1000% and strain-rate-sensitivity coefficient m=0.47 were obtained at the optimal strain rate of 2×10~(-4) s~(-1). Important features of the microstructure and superplastic behavior of the alloy are summarized in the present work. It is shown that microstructure evolution during low-temperature deformation plays a key role in superplastic flow behavior.