Fatigue behaviour of aluminium alloys after anodic and plasma-electrolytic oxidation

电化学转化处理，如阳极氧化或等离子-电解氧化，是提高铝合金耐蚀性和耐磨性的有效方法。具有不同结构和性能的转换层类型直接影响循环荷载作用下的疲劳强度和破坏机理。可调节系统“阳极/等离子-电解氧化层衬底”与疲劳性能之间的复杂关系尚未完全了解。本研究的目的是了解基板和转换层微观结构、层厚度、基板表面加工硬化和氧化层后处理对高周疲劳强度和损伤机制的影响。重点研究了转换层及其显微组织性能、残余应力与疲劳性能、裂纹萌生和裂纹从氧化层向基体过渡之间的关系。

Electrochemical conversion treatments, such as anodic or plasma-electrolytic oxidation, are an effective method to enhance the corrosion and wear resistance of aluminium alloys. The type of conversion layer with the respective structure and properties directly influences the fatigue strength and the failure mechanisms under cyclic loading. This complex correlation between the adjustable system “substrate with anodic/ plasma-electrolytic oxide layer” and the fatigue properties is not fully understood yet. The aim of the proposed research project is to understand the effects of substrate and conversion layer microstructure, layer thickness as well as work hardening of the substrate surface and a post-treatment of the oxide layer on the high-cycle fatigue strength and the damage mechanisms. We focus on the correlation between a conversion layer, its microstructural properties and residual stresses and the fatigue performance, the crack initiation and the crack transition from the oxide layer into the substrate.