激光温喷丸是一种新型的激光表面强化工艺, 即先将材料预热到一定的温度, 再对材料进行激光喷丸处理。相比于常温激光喷丸, 激光温喷丸产生的热-力效应更有利于提高循环载荷和高温下的残余应力和微观组织性能稳定性。温度和激光功率密度是影响激光温喷丸效果的两个重要因素, 本文以Johnson-Cook模型为本构模型, 用Abaqus有限元分析软件模拟分析了不同温度(250、 260、 270、 290、 310 ℃)和激光功率密度I0(7、 8、 9、 10 GW/cm2)下激光喷丸Inconel 718镍基合金后的残余应力分布, 从而确定了激光温喷丸镍基合金的较优工艺参数组合I0＝9 GW/cm2, T＝260 ℃,此时残余应力存在一极大值-489.06 MPa。在此基础上, 选取I0＝9 GW/cm2进行激光温喷丸(260 ℃)和激光喷丸实验, 用X射线应力测定仪和显微硬度计分别对试样的表面残余应力和显微硬度进行测试, 发现表面残余应力和模拟结果一致性较好, 激光温喷丸后的显微硬度相对于基体提高了60%, 比常温激光喷丸后的显微硬度更有所增大。

Warm laser shock peening is an innovative surface treatment by heating up the workpiece before laser peened. The thermomechanical effect of WLSP increase the stability of residual stress and microstructure under high temperature and cyclic loading. Temperature and laser intensity are two important factors of WLSP. This paper analyzed the residual stress contribution of WLSP Ni-based superalloy Inconel 718 under different temperatures(250、260、270、290、310 ℃) and laser intensities (7、8、9、10 GW/cm2),and found that the residual stress is highest when I0＝9 GW/cm2, T＝260 ℃.X-ray stress analyzer and microhardness meter was used to test the residual stress and microhardness of WLSP(260 ℃)and LSP , the results indicated that the experimental residual stress and the simulated results were in good agreement, and the microhardness after WLSP had a 60% increment which is higher than the LSP condition.