Abstract Effects of surface mechanical attrition treatment (SMAT) on fatigue performance of a 7075-T6 aluminium alloy were studied in high cycle fatigue (HCF) and very high cycle fatigue (VHCF) regimes. Fatigue test results showed that SMAT can improve fatigue strength in HCF regime, but decrease it in VHCF regime. Fracture surface observations indicated that the low SMAT intensity is quite optimal, which can protect the surface from crack initiation. However, increasing SMAT intensity could lead to over-peening by inducing deep impact dimples, micro-cracks at the surface and high tensile residual stresses in the subsurface, which deteriorated fatigue performance in VHCF regime.

中文翻译：

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表面机械磨损处理对7075-T6铝合金高周和甚高周疲劳的影响

摘要 在高周疲劳(HCF) 和甚高周疲劳(VHCF) 状态下研究了表面机械磨损处理(SMAT) 对7075-T6 铝合金疲劳性能的影响。疲劳试验结果表明，SMAT 在 HCF 状态下可以提高疲劳强度，但在 VHCF 状态下会降低疲劳强度。断裂表面观察表明，低 SMAT 强度是非常理想的，可以保护表面免受裂纹萌生。然而，增加 SMAT 强度可能会导致过度喷丸，产生深冲击凹坑、表面微裂纹和次表面高拉伸残余应力，这会降低 VHCF 状态下的疲劳性能。