Local deformation and macro distortion of TC4 titanium alloy during laser shock processing

摘要

Experimental investigation has been carried out to understand the local deformation, macro distortion, and residual stress distribution of TC4 titanium alloy thin plate with different thickness during laser peening processing. The results show that the geometry distortions generate different profile directions depending on the laser shock processing condition. The deformation coefficient lambda based on laser power density and sheet thickness is used to predict the macro deformation mode. When lambda < 0.212, no macro distortion is produced; when 0.212 < lambda < 0.58, volume is transferred along the top surface, the geometric distortion direction is away the laser beam, compressive residual stress is induced on the surface, and convex deformation is produced; when 0.65 < lambda, volume is transferred along the bottom surface, the macro distortion direction is toward the laser beam, tensile residual stress is induced on the surface, and concave deformation is produced; the threshold of concave and convex deformation is about 0.62. The deformation coefficient lambda and the threshold of concave and convex deformation can be adopted to predict and control the geometry distortion of TC4 titanium alloy thin plate during laser shock processing.