Tribocorrosion properties and mechanism of a shot peened AISI 4140 low-alloy steel

Many engineering (biomedical, automotive, aerospace etc.) structures suffer from wear and corrosion damage under service conditions and this situation shortens their useful life. In common cases, these damage mechanisms do not act on materials separately. On the contrary, their combined effect called as tribocorrosion cause more decrease in their lifetime than the individual effects of wear and corrosion. Tribocorrosion damages are directly related to surface properties of materials. In order to improve tribocorrosion performance of materials, different surface modifications were applied to enhance their performance and one of them is shot peening. However, tribocorrosion behavior of shot peened materials have not been clarified so far. Therefore, in this study, the effect of shot peening on the tribocorrosion properties of AISI 4140 low-alloy steel was investigated in detail. AISI 4140 samples were shot peened under different Almen intensities and their tribocorrosion performance were examined. The results revealed that the increasing Almen intensity changed the surface characteristics from hydrophobic to hydrophilic. Also, it was determined that the tribocorrosion performance of the material improved with the increasing shot peening intensity in terms of increased surface hardness.