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采用激光熔覆法在TC4钛合金表面原位制备Y2O3颗粒增强Ni/TiC复合涂层,研究涂层的相组成、微结构、成分分布及性能。结果表明,复合涂层内的微结构和成分在深度方向具有分层现象,这主要是由激光熔覆过程的快速熔凝和冷却过程所致。在激光熔覆过程中,TiC粉末完全熔化并在凝固过程中析出为细小枝晶,这些TiC枝晶的尺寸随着深度的增加而减小,而Y2O3颗粒则分布在整个重熔层中。Y2O3颗粒增强Ni/TiC复合涂层具有较均匀的硬度,其最高值约为HV1380,比基体高4倍以上。由于复合涂层具有高的硬度,钛合金经过激光熔覆后其耐磨性得到大幅度提高。
In-situ preparation of Y2O3 particle reinforced Ni / TiC composite coating on TC4 titanium alloy by laser cladding was carried out to study the phase composition, microstructure, composition distribution and properties of the coating. The results show that the micro-structure and composition in the composite coating delaminate in the depth direction mainly due to the rapid melting and cooling process of laser cladding. During laser cladding, the TiC powder completely melted and precipitated into small dendrites during solidification. The size of these TiC dendrites decreased with increasing depth, while the Y2O3 particles distributed throughout the remelt layer. Y2O3 particle reinforced Ni / TiC composite coating has a more uniform hardness, the highest value of about HV1380, more than 4 times higher than the substrate. Due to the high hardness of the composite coating, the wear resistance of titanium alloy after laser cladding has been greatly improved.