Microstructure Study of Compound Layer Fabricated by Coincident Wire-powder Laser Cladding on TC4 Surface

Abstract:

The aim of this paper was to overcome the problem of the poor tribological properties such as high friction coefficient and low hardness of Ti6Al4V. Cladding of metal matrix composites (MMC) layer on Ti-6Al-4V substrate by coincident wire-powder laser deposition was conducted in the paper. During experiment, powder was fed from a coaxial nozzle and wire was fed from a lateral nozzle into the deposition melt pool. Microstructure of compound layer was analyzed by SEM, EDS, XRD. It has shown that compound layer mainly comprises WC, W2C, TiC, α-Ti, W phase. TiC、W2C phase was formed with different morphology at different location of MMC layer. W2C, W and TiC layer can be found at the interface of WC/Ti matrix,. The hardness of compound layer is 570HV0.2 ，which is about 2 times of the hardness of substrate. The friction coefficient of MMC layer was 0.3, while the friction coefficient of Ti substrate was 0.5. Compared to the substrate, the friction coefficient of MMC layer reduced distinctively.