Laser shock induced microstructure strengthening evolution and phase transformation of titanium alloy

Hollow blades are increasingly utilized in aero engines due to their unique thermal cycles during manufacturing, which differ from those of conventional blades. Understanding the microstructural evolution of Ti-6Al-4V after laser shock peening (LSP) treatment is essential for optimizing its mechanical performance. The results indicate that LSP induces the formation of a gradient-distributed microstructure, characterized by significant grain refinement and a high density of dislocations, particularly near the surface after multiple shocks. In addition, the coordinated slip of numerous Shockley partial dislocations during three impacts event triggers a rare phase transformation from hexagonal close-packed titanium (HCP-Ti) to face-centered cubic titanium (FCC-Ti). This transformation has the potential to further enhance the mechanical properties of the material.