Fatigue Behaviour and Fracture Mechanisms in 6063 Aluminium Alloy
Keiro TOKAJI, Zhenzhong CHEN and Yoji GOSHIMA
Abstract:The purpose of the present study is to create a better understanding of the fatigue behaviour in 6063 aluminium alloy. Rotating bending fatigue tests have been conducted using smooth specimens in laboratory air at ambient temperature. Crack initiation site and growth path were found to depend strongly on stress level. Particularly, the stress level dependence of crack initiation site largely changed at a certain stress level, above which the crack initiation was predominantly intergranular, while transgranular below that stress level. Such crack initiation behaviour was significantly related to fatigue life and a morphological change of the S-N curve was seen. Additional fatigue tests were performed using the materials with different grain sizes, and the grain size dependence of fracture mechanisms and associated S-N characteristics are further discussed. Key Words:Aluminium alloy, Fatigue strength, Crack initiation, Small crack growth, Fracture mechanism, Grain size