Sadao Kokubo

Surface Treatment of Aluminum Alloy with Laser Irradition to Increase Wear Resistance

Laser irradiating process with Nd-YAG laser is investigated in order to improve the adhesion and wear resistance of low pressure plasma sprayed layer on the surface of aluminum extruded shape using the atomized powder of Al-50mass%Fe, Al-15mass%Fe-17mass%Si and Al-50mass%Si. The effect of pulse energy of laser beam on the microstructure, micro hardness and wearing rate of these laser irradiated layers are evaluated. Laser irradiated layers have appeared more smooth surface and better adhesion than as sprayed layer. Depth profile of micro hardness where laser irradiated is respectively kept constant. In the microstructure of laser irradiated layer of Al-50mass %Fe, fine needle-like Al3Fe and massive Al2Fe are dispersed. Micro hardness increases with decrease of the pulse energy of laser beam However, the wearing rate of laser irradiated layer increases due to the initiation of cracking. In the microstructure of laser irradiated layer of Al-15mass%Fe-17mass%Si, ultra fine needle-like and massive (Al, Fe, Si) ternary crystals are aggregated. In the microstructure of laser irradiated layer of Al-50mass%Si, ultra fine hyper-eutectic structure is observed. Micro hardness of these layers are HV250-350, HV150-200, respectively and wearing rate of these layer are 1/7 or less than anodized surface.