Effect of Deformation Temperature on the Superplasicity of Titanium Alloy TC11

The superplastic deformation behavior of titanium alloy TC11 has been investigated in the temperature range of 810 similar to 1050 degrees C at the strain rate of 0.001 s(-1) by tensile tests at high temperature, and the microstructures of samples deformed have been observed and analysed by metallographic microscope and transmission electron microscope. The results showed that the titanium alloy TC11 would not exhibit superplasicity in the beta phase field, but exhibit in the temperature range of 810 similar to 980 degrees C in the alpha+beta phase field with an optimal deformation temperature of near 900 degrees C and maximum elongation of 595%. The intracrystalline deformation, interface sliding, dynamic recrystallization or diffusion creep take part in the super-plastic deformation at 900 degrees C, and the interface sliding appears at alpha/beta phase interface. The relative content of alpha and beta phases has a heavy effect on the superplasicity and the titanium alloy TC11 exhibits an optimal superplasicity when the content of primary a phase is about 70%.