WEAR-RESISTANCE OF LASER PROCESSED AL-SI-GRAPHITE(P) COMPOSITES

The surface of an Al-Si-graphite particle composite was melted and sel f quenched after laser beam scans. The microstructure in the laser pro cessed zone was much finer and more homogeneous due to the rapid solid ification. The samples before and after laser treating were aged at di fferent temperatures, leading to different hardness levels. A linear r elationship was found between the wear resistance and hardness in both aged and over-aged samples. The wear resistance of laser processed sa mples was higher than the as cast matrix material. Microscopy of the w orn surfaces' analysis indicated that the ploughing process of the har d particles had caused the damage of the sliding surface. The effect o f ploughing was reduced, and higher hardness were obtained after laser treatment since a homogeneous and fine microstructure, modification o f the eutectic. (C) 1997 Elsevier Science S.A.