Shot peening of a sintered Ni-Cu-Mo steel produced by diffusion bonded powders

The influence of the mechanical properties of a diffusion bonded Ni-Cu-Mo sintered steel on the residua! stresses and the plastic deformation promoted by both steel and ceramic shot peening was investigated. While steel shots deform the surface more extensively than ceramic ones, leading to a thicker surface densification, ceramic shots are more effective in terms of maximum compressive residual stresses. The increase in the yield strength of the base material enhances residual stresses and reduces plastic deformation. The strain induced transformation of Ni-rich austenite in martensite causes a slight decrease of tensile elongation and of impact energy in specimens sintered at low temperature.