为了探究工艺参量对激光增材制造熔覆层残余应力影响规律, 采用数值模拟及实验验证相结合的方法, 取得了激光增材制造熔覆层截面深度方向上沿扫描路径y方向和垂直扫描路径x方向上残余应力的分布规律,并在此基础上进行了不同工艺参量对y方向和x方向应力场影响分析。结果表明, 在一定参量范围内, 随着熔覆层深度的增加, y方向残余应力均表现为拉应力, 呈现先增大后降低趋势, 在熔覆层顶部约0.2mm处存在最大拉应力为262MPa; x方向由压应力逐步转变为拉应力, 其略小于y方向应力值; 随着激光功率的增大, x方向残余应力逐渐增大, y方向残余应力逐渐降低; 随着扫描速率的增大, x方向的残余应力将随之减小, 而y方向的残余应力将随之增大; 随着送粉量的增大, x方向和y方向的残余应力均将随之增大。此研究为降低激光增材制造熔覆层残余应力及工艺参量优化选择提供了指导。

In order to study influence rules of process parameters on residual stress distribution of cladding layers, the numerical simulation and experiments test were adopted. The residual stress distribution rules in depth direction of cladding layer section along the scanning path direction(y-direction) and the vertical scanning path direction(x-direction) were obtained. At the same time, the stress field was also analyzed under different process parameters. The results show that the residual stress of y-direction is tensile stress, which is first increasing and then decreasing, and the maximum tensile stress is 262MPa at 0.2mm position from the top of cladding layer. The residual stress of x-direction is from compressive stress converted gradually to tensile stress, which is less than the value of the y-direction stress with the depth of the cladding layer increasing. The x-direction residual stress gradually increases and the y-direction residual stress gradually decreases with the increasing of laser power. The x-direction residual stress gradually decreases and the y-direction residual stress gradually increases with the increasing of scanning speed. The x-direction residual stress and the y-direction residual stress decreases with the increasing of powder mass flow rate. Meanwhile it can provide a method for decreasing residual stress and optimizing process parameters.