Surface characterization and tribological performance of laser shock peened steel surfaces

Laser shock peening (LSP) is a preeminent surface treatment technique that can surpass many of the modern surface modification processes. Though the wear and surface hardening behavior of the LSP treated surfaces has been extensively investigated, the friction behavior and surface morphological changes due to LSP are not well explored. Hence, the present study focuses on the effect of LSP process parameters on surface morphology and tribological behavior of 1045 steel surfaces. More specifically, the influence of laser intensity on surface roughness and its effect on the coefficient of friction (COF) and transfer layer formation were investigated. The results show that the COF decreased with increasing laser intensity up to a threshold intensity, thereafter, the COF increased with increasing laser intensity. These variation in COF was attributed to the change in surface morphology as a result of applied laser intensity. As the laser intensity increased to a threshold value, the COF decreased as a result of surface strengthening and roughening effects. Beyond the threshold laser intensity, the COF increased as a result of the dominant surface roughening effect.