Probabilistic model for prediction of life based on probabilistic character of defects in PM alloys

Due to manufacturing characteristic, the strength and life of powder metallurgy alloy are sensitive to micro defects, such as nonmetallic inclusion, pores, and nicks on the surface. A distinct character of failure of this kind of material is scatter, which makes life prediction more difficult. In this paper, based on the defect populations of domestic PM alloy and some probability failure methods established in reference [7∼9], definition of the probability for the presence of a defect inside the surface, sub-surface and internal region is given first, and then a probabilistic model is set up, which can calculate the failure probability caused by defects having different shapes and different sizes, being in different regions, and also can calculate the total failure probability. It is concluded that the method can describe the effect of probabilistic character of defects on the strength and life of PM alloy, and it is proved to be valid.