Fatigue behavior of diffusion bonded powder metallurgy steel with heterogeneous microstructure

Fatigue is an important field for the application of powder metallurgy steels in service conditions. The fatigue performance of as-sintered powder metallurgy steel depends on microstructure and density. This concept requires a deep understanding of materials microstructure. Various microstructures in powder metallurgy steels, depending on alloying methods, have different responses against cyclic loading. Focus of this article is to quantify the fatigue behavior of sintered steel material based on diffusion bonded powders in relation to the microstructure. In this study, fatigue behavior of Distaloy AE sintered steels, with two different carbon contents, under different periodic loading have been investigated. Metallugraphy and fractography examinations on fatigue loaded samples revealed the positive effect of microstructure heterogeneity on fatigue cracks behavior.