High-power laser surface treatments in the form of glazing, shock peening, cladding, and alloying can significantly affect material surface properties. In this paper, effects of laser glazing, laser shock peening, and their combination on the tribological behavior of 1080 carbon steel were investigated. Laser glazing is a process in which a high-power laser beam melts the top layer of the surface, followed by rapid cooling and resolidification. This results in a new surface layer microstructure and properties. Laser shock peening, on the other hand, is a mechanical process in which a laser generates pressure pulses on the surface of the metal, similar to shot peening. Five conditions were evaluated: untreated (baseline), laser shock peened only (PO), laser glazed only, laser glazed then shock peened last, and laser shock peened then glazed last (PFGL). In pin-on-disc testing, all laser-treated surfaces reduced dry friction when sliding against alumina, with the PFGL surface having maximum friction reduction of 43%, especially in the early stage of testing. Under lubricated conditions, all laser-treated surfaces except the PO sample lowered friction against alumina. Similarly, all glazed samples showed reduced wear by a factor of 2–3, whereas the peening alone did not change wear significantly. These tribological results are associated with changes in the near-surface microstructure and properties.
Effect of Laser Shock Peening on the Microstructure and Properties of the Inconel 625 Surface Layer
