Crystal and Dislocation Characteristics of Ti-6Al-4V Alloy Under Effect of Laser Shock Peening.

Laser shock peening (LSP) is an effective method for enhancing the fatigue life and mechanical properties of Ti alloys. However, there is limited research on the effects of LSP on crystal structure and dislocation characteristics. In this study, Ti-6Al-4V alloy was subjected to laser shock peening with varying laser power levels. The influence of laser power on the microstructure of Ti-6Al-4V was investigated, with a focus on the evolution of the cross-sectional structure, crystallographic features, and dislocation behavior. These characteristics were analyzed using scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM). Following laser shock peening, the surface grains of Ti-6Al-4V alloy exhibited a distinct preferred orientation and underwent significant refinement, resulting in the formation of nanocrystals. At a laser power of 8 J, the texture strength decreased to 5.19 mud. As laser power increased, a denser dislocation structure and high-density dislocation regions formed at the surface, and the subgrain size further decreased, reaching 66 nm at 8 J. These findings provide valuable insights into grain refinement and property enhancement, contributing to the understanding of process-microstructure-property relationships.