Analysis of Fatigue Strength of High Density P/M Materials by Extreme Value Statistics and Fracture Mechanics

摘要

In order to promote P/M applications, many studies on high strength P/M materials were performed. In TOYOTA group, we developed new P/M applications produced by the original warm compaction with die wall lubrication. We estimated the largest pore length in P/M materials by means of extreme value statistics and simulated their bending fatigue strength by fracture mechanics based on the weakest link model. Thus we clarified that the fatigue strength could be estimated. This allows us to guarantee of lower limit fatigue strength in mass production. As a result, FINE SINTER CO., LTD launched automotive engine sprockets that have higher relative density in 2003.