Fatigue behaviour of iron based sintered material: a review

Abstract

During the last decades, the demand for lower production costs and the reduction of weight resulted in the use of PM iron and PM steel for highly stressed fatigue loaded components. The fatigue behaviour of such PM materials has been described in numerous papers. However, the studies were mostly limited to investigations of the influence of various processing, sintering parameters, and alloying techniques. Relatively few authors applied more basic scientific considerations to understand the fatigue behaviour of sintered iron based material. Thus, a main objective of this review is to consider the characteristic porous microstructure, which may consist of singular isolated pores in a solid structure up to an interconnected three dimensional porous configuration resembling an almost different material. The response of such structures to various stages of the fatigue process, starting from the damaging criteria such as the cyclic plastic strain, to crack initiation and crack propagation will be presented. Considerations in terms of a fracture mechanics approach to such porous structures are proposed. These imply the possibility of predicting some fatigue characteristics which may reduce experimental effort.