Low-temperature superplastic behavior of beta titanium alloy

Abstract

The low temperature superplastic deformation behavior of Ti–3.5Al–5Mo–6V–3Cr–2Sn–0.5Fe alloy were investigated. Results show that the elongation of the alloy exceeds 100% when deformation at the temperature ranging from of 650°C to 800°C and the initial strain rates ranging from 2.78×10−4s−1 to 8.33×10−3s−1, and the elongation of the alloy increases with the decrease of initial strain rates and the increase of temperature. The true strain–stress curves show that the peak flow stress decreases with the decrease of initial strain rates and the increase of temperatures, and the peak flow stress shows much sensitivity to the initial strain rates as well as the temperatures. During superplastic deformation, the α phase was elongated and the size grows up with the decrease of initial strain rates. The superplastic mechanism of the alloy is grain boundary sliding accommodated by dislocation movement and dynamic recrystallization.