Abstract Effects on fatigue behaviors and microstructures of Surface Mechanical Attrition Treatment (SMAT) before or after precipitation aging have been investigated on two hardenable Al alloys. The aluminum alloy with high notch sensitivity (7075) should not be processed by SMAT as the generated low surface integrity is always detrimental to fatigue performances. On less notch sensitive alloys (2024), SMAT before aging formed smaller and denser precipitates, resulting in a high hardened depth, and microstructures more resistant to residual stress relaxation than after conventional shot-peening. SMAT after aging resulted in a significant improvement of fatigue performance with only subsurface crack nucleation sites.

中文翻译：

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严重塑性变形引起的纳米结构表面的表面完整性如何影响具有增强沉淀的铝合金的疲劳行为？

摘要 研究了沉淀时效前后表面机械磨损处理 (SMAT) 对两种可硬化铝合金疲劳行为和显微组织的影响。具有高缺口敏感性（7075）的铝合金不应通过 SMAT 加工，因为产生的低表面完整性总是不利于疲劳性能。在对缺口不太敏感的合金 (2024) 上，时效前的 SMAT 形成更小更致密的沉淀物，导致更高的硬化深度，与传统喷丸处理后相比，微观结构更能抵抗残余应力松弛。时效后的 SMAT 导致疲劳性能的显着改善，只有亚表面裂纹成核位点。