激光形成原位TiC颗粒增强涂层的组织及性能

利用激光熔覆制备了ＴｉＣ颗粒（ＴｉＣｐ）增强金属基复合材料涂层，其中ＴｉＣｐ为激光熔覆过程中原位形成。细小的原位ＴｉＣｐ尺寸为几十至几百纳米，弥散分布于晶粒内部，并在涂层中呈密度梯度分布；高分辨电子显微镜证实了ＴｉＣ／涂层合金的相界面洁净，无界面反应物及非晶结构存在；涂层具有较高的显微硬度及耐磨损性能。

MICROSTRUCTURAL CHARACTERISTICS AND WEAR PROPERLIES OF IN SITU FORMED TiC PARTICLE REINFORCED COATINGS BY LASER CLADDING

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.