IN-SI TU SYNTHESIZED TiN REINFORCED MMC COATINGBY LASER CLADDINGON NiTi ALLOY

Af ter being irradiated by a continuous wave Nd-YAG laser in N₂ environment, the Ti powders preplaced on the surface of NiTi subst rate t ransformed into a TiN reinforced metal mat rix composite (MMC) coating. Acompact laser modified surface coating reinforced with fine TiN can be achieved with optimum process parameters.The amount of TiN reinforcement gradually decreases across the coating. SEM and EDAX result s indicate that thereis a good metallurgical bonding between the hard MMC modified layer and the NiTi alloy subst rate. The mass f raction of Ni in the modified surface coating is very low. Microhardness and wear test result s show that the surfacehardness and wear resistance are significantly enhanced. Laser surface modification can effectively improve the surface composition and performance of NiTi alloy as an implant biomedical material.