激光熔覆原位合成TiC-Cr7C3-Ti-Ni金属复合材料涂层

利用激光熔覆工艺在Ti-6Al-4V合金表面制备出原位自生TiC-Cr7C3-Ti-Ni金属复合陶瓷涂层,以改善材料表面的综合性能。采用X射线衍射(XRD)、扫描电镜(SEM)、能量分散仪(EDS)、电子探针显微分析仪(EPMA)等手段对复合涂层微观组织结构进行研究。结果表明,复合涂层主要由-βTi,-γNi固溶体及分布于晶间的Ti/TiC或Ti/Cr7C3共晶组成;晶内为贫Ni,C的-βTi固溶体组织,晶间为富Ti,C的Ti/TiC和Ti/Cr7C3共晶组织;随着复合涂层成分的变化,激光熔覆原位合成物的量发生相应的变化,涂层熔区内晶体生长形态从网络状晶向树枝晶、等轴晶过渡;复合涂层显微硬度值较基体有显著提高。

Study on Microstructure of In-situ Synthesis of TiC-Cr7C3-Ti-Ni Metal-Ceramics Composite Coating

In-situ synthesized TiC-Cr7C3-Ti-Ni multiphase metal-ceramics composite coating has been fabricated on Ti-6Al-4V surface by laser cladding in order to improve the comprehensive properties of the material. Composite coating were studied by means of X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectrometer (EDS), and electron probe microanalyzer (EPMA). Results show that main phase in the coating is β-Ti and γ-Ni solid solution dendrite with eutectic structure of Ti/TiC or Ti/ Cr7C3 distributing in intergranular. Among the crystal structure is β-Ti solid solution which is poor Ni and C, Ti/TiC or Ti/ Cr7C3 distributes in intergranular which is rich Ti and C. The amount of reinforcement phase varies with chemical composition of the coating, the form of crystal in the coating transfers from network to dendrite and equiaxial crystals. The microhardness of the coating increases prominently compares with the matrix.