Ti-6al-4v Alloy Surface Laser Cladding Wc-12co/nicraly Composite Coating Microstructure And Properties Of,

In this paper, the structure , microhardness and the distribution characteristics of composition of laser clad zone of WC-12Co and NiCrAlY on TC4 were studied. Cross-section of the laser clad zone showed three distinct regions which consisted of clad layer , melt zone and heat-affecting zone The result showed that laser cladding leads to the formation of a continue and compact clad layer. The difference in the composition , temperature and cooling speed in different areas of the coating leads to the result that there are several kinds of structural feathers including dendritic , polgon lumpish , petaloitic, lathy and particulate. The metallurgical combining interface between the cladding layer and matrix is achieved. The maximum of the microhardness of WC-12Co and NiCrAlY layers cladded by laser comes up to 1100HV.The influence of laser power and coating thickness on the microhardness of the clad zone ,on the thickness of clad-layer and the depth of melt zone were studied using scanning electron microscope(SEM) and microhardness testing techniques. The result showed that given the WC-12Co and NiCrAlY coating thickness constant, the depth of clad-layer increases while the microhardness of clad zone decreases with the increment of laser power .There is a process of convection at the bottom of the melting pond, where the alloy elements flows upwards, and the alloy element,W, Cr , Ni, Co etc. in coating layer, flows down. The effect of convection differs with the laser power. The alloy elements in the melting pond distribute more equably when the laser power is stronger.The paper applies the orthogonal experiment to design suitable organization of the process parameters, the part with high qualities were achieved by control the corresponding process parameters.