LAUSR

Abstract In this paper, Ti/TiBCN reinforced Ti based composite coatings were prepared on Ti6Al4V alloys. The influence of the scanning speed on the dilution rate, microstructure and properties was studied. Results showed that when the scanning speed increased from 3 mm/s to 9 mm/s, the dilution rates of the composite coatings presented a decreasing tendency, the microstructure of the composite coatings was basically the same, with short whisker AlTi-Al3Ti phases as the intermetallic matrix and numerous rod-like and dendritic TiBCN, block-shaped TiB2, white polygonal TiN, white needlelike and granular TiC as the reinforcing phases uniformly dispersed throughout. Furthermore, when the scanning speed was 7 mm/s, the microstructure of the coating was finer and less defects. In addition, with the scanning speed going up, the microhardness of the composite coatings first increased and then decreased, the maximum value (1074 HV0.2) was obtained in the coating with a scanning speed of 7 mm/s, which was 3 times that of the substrate (350 HV0.2). The coefficient of friction, wear mass loss, wear volumes, and energy dissipation of the composite coatings first deceased and then increased, and the best wear resistance occurred when the scanning speed was 7 mm/s.