为了实现某镍基高温合金涡轮叶片榫槽结构复杂部位的激光冲击强化(LSP),进行了不同激光脉冲能量下某涡轮叶片材料K417的激光冲击强化试验,分析了强化参数对材料表面粗糙度、显微硬度和微观组织的变化规律,确定了该材料激光冲击强化工艺参数;并通过振动疲劳对比试验研究了激光冲击强化对材料模拟试件疲劳性能的影响。结果表明,激光冲击强化对材料表面粗糙度影响不大,能提高表层材料显微硬度,影响深度达0.7 mm以上;强化后表层材料的X射线衍射峰宽化明显,位错密度增加,激光冲击强化提高榫槽模拟试件疲劳寿命达67%。

In order to improve the fatigue strength of the blade,the Ni-based superalloy laser shock peening (LSP) parameters and method are researched. After laser shock peening on the Ni-based superalloy(K417),the surface roughness,micro-hardness,and microscopic structure are analyzed,and the parameters are determined for LSP. Then the fatigue performance is tested by means of vibration fatigue test adopting the samples with the same groove in a turbine blade. The results indicate that LSP changes the surface roughness lightly,but increases the micro hardness evidently and the depth affected by LSP is up to 0.7 mm. The breadth at half height of the X-ray diffraction peak after LSP indicates that the plastic deformation occurres in the LSP part,and the dislocation density and micro-residual stress increase,which are advantageous to the fatigue performance. The vibration fatigue tests prove that the fatigue life with LSP is 1.67 times longer than that without LSP.