LASER IN SITU SYNTHESIZED TiN/Ti3Al COMPOSITE COATINGS
Utilizing the high-temperature chemical reaction between Ti and A1N, TiN reinforced Ti3Al composite coating was in situ synthesized on TC4 alloy substrate by laser cladding technique. The phase constitution and microstructure of treated samples were examined by XRD and SEM. The results reveal that the coating is mainly composed of TiN and Ti3Al phase. When the molar ratio between Ti and A1N is 4: 2, the content of TiN reduces as the laser power density increases; whereas when the molar ratio between Ti and A1N is 4 '. 1, the content of TiN increases with increasing the laser power density. SEM observation shows that the morphology of TiN changes gradually from bar-shaped to granular with the increase of laser power density. When the molar ratio between Ti and A1N is 4:1 and the laser power density is 15.28 kW·s·cm-2, the macro-morphology of surface coating is better, no pores and cracks appear. The average microhardness of laser cladding coating is 3.4 times larger than that of TC4 alloy substrate.
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万方数据
维普
