为了研究激光冲击处理对GH3039高温合金疲劳寿命的影响,采用Procudo200型激光喷丸系统对GH3039高温合金薄板试样表面进行冲击处理;然后采用光学显微镜观察激光冲击前后试样表层的微观组织,采用X-350A型残余应力测定仪测试激光冲击前后试样表层的残余应力,采用MTS Landmark 370.10 电液伺服试验系统进行疲劳试验,并利用∑IGMA500 型扫描电子显微镜观测疲劳试样的断口形貌。结果表明:激光冲击处理后合金表层晶粒明显细化,试样表面激光诱导的平均残余压应力达到了-255.07 MPa左右,试样的表面粗糙度由0.0346 μm增大到0.048 μm,激光冲击试样的疲劳寿命是原始试样的2.41倍;残余压应力和晶粒细化是激光冲击GH3039高温合金试样疲劳寿命延长的关键因素。

In this study, the GH3039 superalloy sheets were treated by using a Procudo200 laser shock peening (LSP) system to study the effect of LSP on the fatigue life of the GH3039 superalloy. Further, the microstructure and residual stress of the samples before and after LSP were characterized by using an optical microscopy and an X-350A residual stress tester, respectively. The fatigue life tests for the samples before and after LSP were performed by using an MTS Landmark 370.10 electro-hydraulic servo test system, and the fracture morphologies of the samples were characterized by using a ∑IGMA500 scanning electron microscope. The experimental results denote that the grain size of the surface layer of the superalloy is refined by LSP. The average residual stress induced by LSP becomes -255.07 MPa at the sample surface, and the surface roughness increases from 0.0346 μm to 0.048 μm. Furthermore, the fatigue life is observed to be improved by 2.41 times after LSP. Finally, the increase in fatigue life of the LSP-treated GH3039 superalloy can be mainly attributed to the residual compressive stress and grain refinement.