The twins of α2 phase in β-solidifying TiAl alloy during high strain rate rolling

Abstract

High strain rate rolling (HSRR) was successfully used to produce TiAl alloy sheets at average strain rate of 7.23 s−1. In present study, β-solidifying Ti-42Al-9V alloys were rolled with a single pass reduction of 80 % within (α + γ) double phase region at 1250 °C. The microstructure of the Ti-42Al-9V alloy sheet was mainly composed of fine needle-like β/γ mixture structure and the block α2 phase which was divided into different contrast by mechanical twins. As investigated, {1 1 2¯ 2}〈1 1 2¯ 3¯〉 contraction twins are the main component. And few {1 0 1¯ 2}〈1 0 1¯ 1¯〉 extension twins are generated in {1 1 2¯ 2}〈1 1 2¯ 3¯〉 primary contraction twins, namely {1 1 2¯ 2}-{1 0 1¯ 2} secondary twinning. Besides, multiple parallel twins and intersectional twins were activated.