Study on the dynamic deformation behavior and microstructure evolution of Ti-5Al-2.5Sn utilized Quasi-In-Situ method

Abstract

In this paper, the microstructural evolution process and deformation mechanism of annealed Ti-5Al-2.5Sn alloy under a high strain rate of 2700 s−1 were investigated by quasi-in-situ method. The main deformation mechanism is found to be dislocation slip in the strain range from 0 to 0.05, and about 96% of the whole grain is deformed by dislocation slip, and prismatic slip dominates the plastic deformation. When the strain increased from 0.05 to 0.10, the original slip system continued to move, and 13% of the whole grain activates the new slip system. In the strain range from 0.10-0.20, the number of slip traces does not increase significantly, and the new slip system is difficult to be activated. In the whole deformation process, about 42% of whole the grain activates a variety of slip systems including prismatic slip and pyramidal <a> slip which activated at the same time. Results show that twin only appeared in a few grains in the whole observed region, indicating that twinning is not the dominant deformation mechanism of annealed Ti-5Al-2.5Sn alloy at a high strain rate.