Abstract The corrosion-fatigue response of Al alloys becomes an important consideration for qualifying them for aerospace and other structural applications, the MAO coatings with three different thicknesses namely 10 µm, 50 µm and 90 µm were provided on peened (SP+MAO) and un-peened (Plain MAO) substrates. Further, the corrosion (potentiodynamic polarization) tests in 3.5 wt. % NaCl solution and corrosion-fatigue tests at 5-different maximum alternating stress levels were evaluated for each material condition. In addition, the surface roughness, surface and cross-sectional coating morphologies in as deposited and corroded conditions; fractured morphology and corrosion-fatigue crack propagation features were evaluated; correlated with the corresponding corrosion rates and corrosion-fatigue life. The results obtained highlight the role of corrosion medium in significant degradation of corrosion-fatigue life as compared to the plain-fatigue life of both bare substrate and MAO coated conditions. A new parameter namely the normalized corrosion-fatigue life index (NCFI) provides a quicker insight and possible benchmarking of the coating’s ability to withstand the damaging action of simultaneous corrosion and fatigue. A 50 µm thick SP+MAO coating was identified as a candidate choice to withstand diverse degradation modes namely the simple corrosion, plain-fatigue and corrosion-fatigue.

中文翻译：

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微弧氧化涂层6061-T6铝合金的腐蚀疲劳行为

摘要 铝合金的腐蚀疲劳响应成为使其在航空航天和其他结构应用中合格的重要考虑因素，在喷丸 (SP+MAO) 和 un -喷丸（Plain MAO）基材。此外，腐蚀（动电位极化）测试在 3.5 重量。对于每种材料条件，评估了 5 种不同最大交变应力水平下的 % NaCl 溶液和腐蚀疲劳试验。此外，沉积和腐蚀条件下的表面粗糙度、表面和横截面涂层形态；评估了断裂形貌和腐蚀疲劳裂纹扩展特征；与相应的腐蚀速率和腐蚀疲劳寿命相关。与裸基体和 MAO 涂层条件的普通疲劳寿命相比，获得的结果突出了腐蚀介质在腐蚀疲劳寿命显着降低方面的作用。一个新参数，即归一化腐蚀疲劳寿命指数 (NCFI)，提供了更快的洞察力和可能的涂层承受同时腐蚀和疲劳破坏作用的能力的基准。50 µm 厚的 SP+MAO 涂层被确定为可承受多种退化模式的候选选择，即简单腐蚀、普通疲劳和腐蚀疲劳。一个新参数，即归一化腐蚀疲劳寿命指数 (NCFI)，提供了更快的洞察力和可能的涂层承受同时腐蚀和疲劳破坏作用的能力的基准。50 µm 厚的 SP+MAO 涂层被确定为可承受多种退化模式的候选选择，即简单腐蚀、普通疲劳和腐蚀疲劳。一个新参数，即归一化腐蚀疲劳寿命指数 (NCFI)，提供了更快的洞察力和可能的涂层承受同时腐蚀和疲劳破坏作用的能力的基准。50 µm 厚的 SP+MAO 涂层被确定为可承受多种退化模式的候选选择，即简单腐蚀、普通疲劳和腐蚀疲劳。