Abstract: In order to research the effect of micro defects on the performance of powder metallurgy (PM) turbine disk, a reliability calculation model based on the probabilistic character of distribution of defects is established by using the results of finite element analysis, which is aimed at the failure mode of crack initiation and propagation under low cycle fatigue. The model can be used to calculate the reliability of PM turbine disk under different distribution of defects and different cyclic loading conditions. Then failure analysis of a PM turbine disk indicates that the surface quality is an important factor leading to failure of PM turbine disk, and that is in good agreement with a great deal of experimental results. So the model can be used to guide the engineering design and application of PM turbine disk.

Key words: Critical size, Defects, Powder metallurgy turbine disk, Reliability