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

阳极氧化或等离子体电解氧化等电化学转化处理是提高铝合金耐蚀耐磨性的有效方法。不同结构和性能的转换层的类型直接影响疲劳强度和循环载荷下的失效机理。这种可调节系统“具有阳极/等离子体-氧化层的衬底”与疲劳性能之间的复杂关系尚不完全清楚。该研究项目的目的是了解基板和转换层的组织结构、层厚度以及基板表面的加工硬化和氧化层的后处理对高周疲劳强度的影响和损伤机制。重点研究了转化层及其组织性能和残余应力与疲劳性能、裂纹萌生以及从氧化层到衬底的过渡过程之间的关系。

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.