10.4.2017 Pressing & Sintering

Fatigue of heat treated PM steels – a fracture mechanics approach

Fatigue is one of the most common failure mechanism for components subjected to mechanical load. Therefore it is of key importance to have reliable models to describe the fatigue strength of materials and components. This paper describes how a fracture mechanics based model can be used to take both density and notch effects into account. First the porosity is described using extreme value statistics, and then the largest pores linked to the fatigue strength by linear fracture mechanics. It is demonstrated how this concept can be used to estimate the fatigue strength for test bars with different densities and stress concentrations, requiring only a minimum of fatigue testing.