Study on the Laser Shock Processing with Square Spot of Titanium Alloy Based on ABAQUS

Abstract

Laser shock processing is a new kind of technology to improve the physical and mechanical properties of the metal surface. It uses the high-amplitude stress wave produced by the interaction of short-pulse laser and material, to make the material produce the compressive residual stress and refinement internal structure, and lead to the improved hardness and strength of material. In this paper, the simulation of laser shocking process with square spot of Titanium alloy plate was carried out through ABAQUS. The influences of the shock time, laser energy, plate thickness and spot size on the strengthening are investigated from the view of residual stress. The results show that: There are the compression residual stress in the workpiece surface after laser shcok processing, and its amplitude is about 300-400Mpa. With the increase of shock time, the surface residual stress increases, the area and depth of strengthening zone also increase. The strengthening area becomes a circular, while the distribution of residual stress becomes unhomogeneous. The surface residual stress increases as the laser energy increasing, but the amplitude is smaller. The plate thickness does not affect the amplitude of the surface residual stress. When the shock pressure is constant, surface residual stress does not change with the spot size. However, if the laser energy is constant, due to the shock pressure will decrease with the increase of spot size. Therefore, there should be an optimized spot size when the strengthening effectiveness and efficiency are both considered.