Dynamic recrystallization of Ti-6Al-4V alloy promoted by laser shock peening

Abstract

In this study, the influences of different numbers of passes of laser shock peening (LSP) on the surface microstructures of Ti-6Al-4V alloy were investigated. Especially, the microstructural evolution of the As-received (AR) sample and LSP treated samples was observed by scanning electron microscope (SEM) and electron backscatter diffraction (EBSD) observations. The results showed the grain size and the distribution of α, β phase have changed after the LSP process. After 1 LSP processing, the grain size is more uniform, the β phases were transformed from scattered and laminar characteristics to linear characteristics, while the α phases were parcelled by the β phases. After 2 LSP treatment, obvious grain refinement can be observed and the influence depth is deeper compared to the 1 LSP sample. After laser shock peeing processing, the material also has obvious dynamic recrystallization (DRX). Finally, the mechanism of microstructure evolution by LSP was revealed.