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

Abstract

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 { 1 1 ¯ 00 } < 11 2 ¯ 0 > 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 { 1 1 ¯ 00 } < 11 2 ¯ 0 > prismatic slip and { 1 ¯ 101 } < 11 2 ¯ 0 > pyramidal <a> slip which activated at the same time. Results show that { 11 2 ¯ 1 } 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.