Evolution of the microstructure and tribological performance of Ti-6Al-4V cladding with TiN powder

Titanium nitrides (TiNs) powder was used as a material to resist wear; it was then clad onto a Ti-6Al-4V substrate by gas tungsten arc welding (GTAW). During the cladding process, the TiNx reinforcing phase was formed in situ within the clad layer. Since the TiNx reinforcing phase exists within the clad layer, the hardness of the clad layer is double that of the substrate. Wear test results reveal that the wear resistance of TiN clad layer is up to ten times more resistant than the Ti-6Al-4V substrate. From the worn surface analysis, the primary wear mechanism of the Ti-6Al-4V specimen exhibited oxidation wear combined with adhesive wear, and the TiN clad layer specimen exhibited abrasive wear. This investigation also discusses the mechanism for forming the clad layer microstructure. During solidification of the clad layer, the motion of the liquid-solid interface caused the oval TiNx phase to cluster, producing a dendritic appearance. (C) 2011 Elsevier Ltd. All rights reserved.