Theoretical and experimental study of the contact fatigue behavior of a Mo-Cu steel produced by powder metallurgy

A conservative approach to predict the contact fatigue behavior of a Powder Metallurgy steel, in the sinter-hardened condition and after shot peening, was proposed. It is based on the assumption that the contact fatigue crack nucleation is anticipated by the local plastic deformation of the material, which occurs when the maximum local stress exceeds the yield strength of the matrix. A model to predict contact fatigue crack nucleation has been proposed and validated by experiments. A local approach is used, based on the characteristics of the largest pores, which promote fatigue crack nucleation, and on the microhardness of the microstructural constituents where they are localized. Shot peening improves the contact fatigue resistance of the sinterhardened steel by 30%.