Microstructure and property of composite coatings on titanium alloy deposited by laser cladding with Co42+TiN mixed powders

摘要

In this study, composite coatings were fabricated on Ti-6Al-4V alloy by laser cladding with Co42 Co-based self-fluxing alloy and TiN mixed powders. Microstructures and wear resistance of the cladding coatings with 20 wt% and 30 wt% TiN addition were investigated comparatively. The composite coatings were mainly comprised of gamma-Co/Ni, CoTi, CoTi2, Co3Ti, NiTi, TiN, CrB, Cr7C3, TiC, TiB, and TiC0.3N0.7 phases. The composite phase components were beneficial to the improvement of the micro-hardness and wear resistance. Results showed that the micro-hardness of the composite coatings was 3-4 times the Ti-6Al-4V substrate and the wear resistance was enhanced as high as 18.2 times. With more TiN addition, the micro-hardness and wear resistance of the laser cladding coating were improved further. The microstructure, strengthening mechanism, and wear mechanism of the laser cladding coatings were investigated accordingly. (C) 2016 Elsevier B.V. All rights reserved.