Abstract
According to the statistical analysis by one of the authors, more than 90% of failure is caused by fatigue, and more than 90% of failure causes are initiated from the notched portion. It is very important to improve the fatigue strength of the notched portion in the practical components. Roller working is one of the effective plastic working method to improve the fatigue strength of materials such as carbon steels. In this study, roller work process was used to notched pure aluminum specimens for estimating its effect on fatigue properties. The result of fatigue test indicates that the fatigue strength by 10^7 cycles of specimens after roller working increases by 30% compared to non-roller worked specimens, but with the increase of roller working value, the fatigue strength by 10^7 cycles decreases gradually. The crack propagation behavior was also investigated by taking replicas and observations under an optical microscope. The change in fatigue strength was discussed according to the concept of compressive residual stress at the notch root and the surface condition after roller working.
