Structure property relationships in porous sintered steels

The flat bending fatigue strength of a variety of carbon-free iron base sin tered materials has been investigated varying density, sintering temperatur e and particularly the morphology of the base powder. All effects that lead to round pores improve the fatigue performance. The porosity of sintered i ron and steel is characterised by a large majority of tiny spherical pores and a few big pores of high irregularity. It is this small fraction of larg e and irregular pores with their pronounced internal stress concentration w hich determines the fatigue strength of sintered porous materials, next to overall density and alloying effects. (C) 2001 Elsevier Science B.V. All ri ghts reserved.