Numerical investigation on laser-produced microstructure of metal under non-melting condition

Surface topography plays an important role on the improvement of tribological properties under hydrodynamic or elasto-hydrodynamic lubrication conditions. Laser texturing processes that give a regular surface topography have been extensively analyzed, however, the micro-convex features produced have a regular volcano profile which is not in favor of dynamic pressure lubrication and enhancing the wear-resistant ability. To obtain a functional surface topography, a new process method by laser non-melting is proposed. The forming mechanism of the micro-convex features produced has been analyzed. The main reason for the formation was found to be due to the free expansion of the heating area being restricted by the surrounding cool material. The effect of different process parameters on the height and width of the micro-convex features is investigated. Finally, a scanning strategy to control the surface micro-convex feature length is presented. The numerical results show that smooth micro-convex features can be achieved by selecting the correct heating paths and process parameters.