Effects of Different Laser Shock Processes on the Surface Morphology and Roughness of TC4 Titanium Alloy

In order to solve the irregular surface morphology introduced by laser shock processing, actively control the spot boundary effect and effectively reduce surface roughness. In this paper, a laser shock imprinting technology for actively designing surface morphology was proposed, and the effects of different laser shock processes on the surface morphology and roughness of TC4 titanium alloy were investigated by simulation and experiment. In the simulation, ABAQUS software was used to simulate the dynamic deformation behavior of the workpiece surface under single point impact, so as to reveal the mechanism of surface morphology forming. Meanwhile, the surface morphology under 33% and 50% spot overlapping impacts were investigated. In the experiment, the surface morphology was verified under single point and overlapping impacts, and the surface roughness was measured. The results showed that compared with laser shock processing, both laser shock wave planishing and laser shock imprinting can reduce surface roughness, which was significantly reduced when 33% spot overlapping impact was used; compared with laser shock processing and laser shock wave planishing, laser shock imprinting can achieve the active design of surface morphology under the premise of guaranteeing the reduction of surface roughness, effectively controlling the spot boundary effect, and 50% spot overlapping impact can make the surface morphology more uniform under laser shock imprinting. The special plastic rheological behavior of laser shock imprinting technology will provide a new way for metal surface morphology to be transformed in a direction conducive to improving its fatigue properties.