MICROSTRUCTURAL CHARACTERISTICS AND WEAR PROPERLIES OF IN SITU FORMED TiC PARTICLE REINFORCED COATINGS BY LASER CLADDING
激光形成原位TiC颗粒增强涂层的组织及性能

A new method was realized to produce a Ni-alloy composite coating reinforcedby in situ reacted and gradiently distributed TiC particles (TiCp) by one step laser cladding.TiCp was introduced by an in situ reaction of titanium and graphite during laser clad process.It was observed that the disperse TiCp with size of sub-micrometer formed in the layer. And,TiC. possessed density--gradient distribution and a maximum volume fraction of 38% at thelayer surface. Furthermore, the in situ generated TiCp/matrir interfaCes is found to keep cleanand free from deleterious surface reactions. The microhardness revealed a gradient variationwith the layer depth,and the highest value was 1250 HV0.2. The wear properties of the layeris significantly enhanced due to a large amount of TiCp and strong phase interface combinationwithout evidently increasing the friction coefficient.