抄録
Lead is added to traditional free-cutting brass. However, lead is dangerous to the human health and environment. So, Bi brass has been produced as an alternative to the lead brass. In this study, fatigue test was conducted at room temperature using the lead free brass, i.e., Bi brass. The material was clarified to be consist of three phases, a, R and Bi phases. A crack was initiated at Bi phase existing in specimen surface at the early stage of fatigue life. The Bi phase is much softer than the other phases. Prediction of fatigue life was carried out on the basis of crack propagation behavior. The predicted result was in good agreement with the experimental value. It was also clarified that the smaller the size of Bi phase, the longer the fatigue life.
