Superplasticity and Microstructure Evolution of Ti75 Alloy in a Compression Testing

The superplasticity and microstructure evolution of Ti75 alloy in a compression testing were studied. The result showed that the strain rate sensitivities, m, was more than 0. 3 at 800°C, 5 × 10^-4s^-1 and 850°C, 1 × 10^-1s^-1, but m value reduced at 900°C. Dynamic recrystallization and diffusion of β phase made the lath-like grain become equiaxed, refined and homogeneous, which created a better condition for grain sliding and rotation. In the whole deformation process, diffusion and dislocation movement act as both deformation mechanisms and assommodation ones for boundary sliding.