Abstract Surface gradient stress distribution was prepared on AISI 420 martensitic stainless steel (MSS) by massive laser shock peening treatment (MLSPT) with different pulse energies, and effects of MLSPT on residual stress and corrosion fatigue properties in NaCl solutions with different pH values were investigated by microstructural observation, residual stress measurement, corrosion fatigue test, and fractural morphology. Results showed that the coupling effect of MLSPT-induced surface microstructural evolution and gradient stress distribution effectively contributed to an extension in corrosion fatigue properties. Furthermore, the corrosion fatigue crack growth rate equation considering both gradient compressive residual stress and pH value was developed.

中文翻译：

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激光冲击强化表面梯度应力分布及AISI 420不锈钢腐蚀疲劳寿命延长机制

摘要 对AISI 420马氏体不锈钢(MSS)采用不同脉冲能量的大规模激光冲击强化处理(MLSPT)制备表面梯度应力分布，研究MLSPT对不同pH值NaCl溶液中残余应力和腐蚀疲劳性能的影响。通过显微组织观察、残余应力测量、腐蚀疲劳试验和断裂形貌。结果表明，MLSPT 诱导的表面微观结构演变和梯度应力分布的耦合效应有效地促进了腐蚀疲劳性能的扩展。此外，建立了考虑梯度压缩残余应力和pH值的腐蚀疲劳裂纹扩展速率方程。