Study on Multi-steps Dynamic Compression Deformation Behavior of Ti-5.5Al Alloy

Abstract

The microstructure evolution in a specific area with typical characteristics of the Ti-5.5Al alloy was studied under multi-steps dynamic compression condition at a strain rate of 4000s-1 by EBSD/SEM method. Both twinning and dislocation movement were proved to be the deformation mechanism. However, the dominant deformation mechanism was greatly influenced by strain. During the strain level from 0 to 0.05, the most important deformation mechanism of Ti-5.5Al alloy was dislocation slip. During the deformation process of strain 0.05 to 0.10, the main deformation mechanisms were the {1012} of twin and dislocation movement. The rapid expansion of existing twins causes significant changes of texture. During a strain level from 0.10 to 0.15, the main deformation mechanism was twinning, while the dislocation movement dominated the deformation when the strain increased from 0.15 to 0.20. Besides, dislocation was proved to active prior to twinning.