7050铝合金激光冲击强化的试验和数值模拟

Experiment and numerical simulation of laser shock processing in 7050 aluminum alloy

依据激光冲击强化7050铝合金的试验,建立激光冲击强化的有限元模型,实现激光冲击强化的数值模拟,残余应力场的数值模拟结果与试验结果取得较好的一致.在不考虑各冲击参数之间交互作用的前提下,模拟研究冲击参数对残余应力场的影响.模拟结果表明:在激光功率密度小于一定阀值条件下,表面残余压应力最大值随激光功率密度增加而增加,超过阀值之后,表面残余压应力最大值减小;表面残余应力最大值和残余压应力层深度随着脉宽的增加而增加;通过增加光斑半径对残余压应力场的改善主要体现在对深度方向残余应力场的改善;多次连续冲击强化对残余应力场的改善效果比较明显.

According to the experiment of 7050 aluminum alloy by laser shock processing,a finite element model was established to carry out the numerical simulation.The numerical results showed good agreement with the experimental data.Without considering the interaction between the shock parameters,the effects of laser shock parameters on the residual stress field of 7050 aluminum alloy were studied by simulation.The results indicate that increasing the laser power density until a fixed value results in a large peak surface residual compressive stress;increasing laser pulse duration results in the maximum depth of the residual compressive stress;increasing the laser spot size can improve the residual compressive stress in depth;and multiple laser shock processing can improve the residual compressive stress greatly.