TC4钛合金激光搭接冲击强化的实验和数值模拟

Experiment and numerical simulation of overlapping laser shock processing in TC4 titanium alloy

为了研究激光搭接冲击时残余应力场的特征以及激光冲击参量对搭接区残余应力场的影响,采用高功率钕玻璃激光系统对TC4板进行了激光搭接冲击实验,同时利用有限元软件ANSYS对激光搭接冲击过程进行了模拟,残余应力场的数值模拟结果与实验结果取得较好的一致。结果表明,在不考虑各冲击参量之间交互作用的前提下,搭接区表面残余压应力值和残余压应力场深度随搭接率增加而增加,但达到一定阈值后,残压应力场深度会下降;搭接区表面残余压应力值和残余应力场深度会随着功率密度的上升而增加;在脉宽小于一定阈值条件下,搭接区表面残余压应力随脉宽增加而增加,超过阀值之后,表面残余压应力减小,但残余压应力层深度一直是随着脉宽的增加而增加。

In order to study the characteristics of the residual stress field, the effect of laser shock parameters on residual stress field in overlapping area, overlapping laser shock of TC4 Titanium alloy was carried out with high-power Q-switched, pulsed neodymium-glass laser. Then the process of overlapping laser shock was simulated with ANSYS. The numerical results showed good agreement with the experimental data. Without considering the interaction between the shock parameters, increasing the overlapping rate, the laser power density and the laser pulse duration, the surface residual compressive stress and the depth of residual compressive stress field in overlapping zone can be increased. However, if the overlapping rate and laser pulse duration exceeds a threshold value, the depth of residual compressive stress field and the value of surface residual compressive stress in overlapping zone decline respectively with the increase of the overlapping rate and the laser pulse duration.