Microstructure and properties of Ti–Al–C composite coatings prepared by laser cladding

Abstract

The high-temperature wear resistance of Ti alloys was improved in the work, with their application in the hot-end parts of engines expanded. Laser cladding was used to clad TiC/TiAl powders with different molar ratios on the Ti6Al4V surface for hardness, friction, and wear tests. Laser cladding was used to explore the structural transformation rules of composite coatings with different components. The formation mechanism of Ti2AlC MAX phases was revealed, with the wear mechanism of the substrate and coating analyzed. Results indicated the ideal metallurgical properties of the coating and substrate. The structure and performance of the coating were controlled by adjusting the molar ratio of the two-component system. Ti2AlC MAX phase content in the coating increased significantly with increased TiC content. Al powders improved the metallurgical chemical reaction inside the molten pool, which enhanced the coating quality. The cladding coating increased the hardness of the plates—approximately two times higher than that of the substrate. The TiC/TiAl coating improved the wear resistance of Ti plates under a wide temperature range. The main wear of the coating and Ti plate at room temperature to 600°C is primarily abrasive wear. The work laid the foundation for preparing MAX phase composite coatings by laser cladding. The coating-grain structure of the Ti alloy surface was refined, with the wear resistance of the material improved.