The aspect of the corrosion pitting with fretting fatigue on Aluminum Alloy: A nuclear reactor safety or an aerospace structural failure phenomenon

Abstract

Since wear and other surface decaying processes as Stress Corrosion Cracking (SCC) and Gridto-rod fretting failure (due to fuel rod vibration) can risk the lifespan of nuclear reactors, surface modification and other life degradation reducing attempts are being adopted for Aluminum alloys in such sophisticated applications like nuclear or aerospace components. In this research work, fretting fatigue and artificial pitting effect on heat-treated Al-Mg-Si alloy (Al 6061-T6) have been studied. Experimental observations have been authenticated by developing a FEM (Finite Element Method) model using simulation software ANSYS. Fretting causes a noticeable reduction in fatigue life at high cycle fatigue tests. However, it is difficult to differentiate between fretting and normal fatigue curve lines at low cycle fatigue. The fracture surface schematic shows how fretting affects crack initiation to final rupture. Interestingly, it has been found that pitting reduces the lifetime of Aluminum more abruptly than normal and even fretting fatigue. This study suggests more concentration on pitting by corrosion or others as well as geometry irregularities than the fretting aspect comparatively.