In this work, the effect of a novel post process integrating laser shock peening (LSP) with shot peening (SP) on the fatigue property of Ti-6Al-4V titanium alloy is investigated. The fatigue life can be improved (up to 9.3 times) by this post-process. The compressive residual stress (CRS) distribution and dislocation-gradient microstructure obtained were found to be responsible for the improvement. The fatigue crack initiation was hindered by the high-density dislocation layer with high CRS value on the surface and maximum CRS in the sub-surface, while the crack propagation was retarded by the dislocation proliferation layer with large CRS gradient.

中文翻译：

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激光冲击强化、喷丸强化及其组合对Ti-6Al-4V钛合金组织和疲劳性能的影响

在这项工作中，研究了一种将激光冲击强化 (LSP) 与喷丸强化 (SP) 相结合的新型后处理对 Ti-6Al-4V 钛合金疲劳性能的影响。通过该后处理可以提高疲劳寿命（高达 9.3 倍）。发现所获得的压缩残余应力 (CRS) 分布和位错梯度微观结构是改进的原因。疲劳裂纹萌生受到表面高CRS值和亚表层CRS最大的高密度位错层的阻碍，而CRS梯度大的位错扩散层阻碍了裂纹扩展。