Effect of severe vibratory peening on microstructural and tribological properties of hot rolled AISI 1020 mild steel

In this study, microstructural and mechanical performance of AISI 1020 were investigated after severe vibratory peening (SVP) for emerging the potential and performance of this novel treatment among surface severe plastic deformation (SSPD) methods. The specimens were subjected to SVP treatment of V1, V2, and V3 conditions at 20, 40 and 60 min. durations, respectively. Optical microscope (OM) and SEM images demonstrated two layered gradient structure. XRD analysis showed the oxide layer was completely vanished besides surface nanocrystallization by severe plastic deformation (SPD). The microhardness test revealed an average improvement of 48% compared to the untreated specimen. SVP caused raising of hardness from surface to a depth of approximately 900 μm. In wear tests, the volume loss after SVP were less. The hardness improvement due to deformation overcame the negative effect caused by roughness increase. However, the friction coefficient of the unpeened specimen was the lowest at all loads.