Microstructure and Properties of Laser Clad Ni-Base Intermetallic Alloys Reinforced with Carbide Particles

Microstructure and hardness of two-phase Ni3Al and Ni3V intermetallic alloy layers reinforced with VC, NbC and WC particles, which were clad by laser metal deposition on SUS304 steel, were studied, focusing on the effect of the charged carbide species. In VC and NbC composite layers, premature microstructure composed of Ni solid solution and Ni3Al phase was developed in as-clad layers while stable microstructure composed of the Ni3Al and Ni3V phases was developed in annealed one. Hardness level in the both composite layers was increased by annealing. In WC composite layer, microstructure composed of the Ni3Al and Ni3V phases was developed in as clad layer while microstructure composed of Ni solid solution and Ni3Al phase was developed in annealed one. Hardness level in the WC composite layer was conversely decreased by annealing. The VC and NbC particles were relatively stable during cladding as well as annealing, resulting in unaffected matrix composition. The WC particles were unstable, resulting in degenerated matrix composition. The present work reveals that reinforcement of VC and NbC particles into the two-phase Ni3Al and Ni3V intermetallic alloy is favorable as cladding layer from the point of microstructural stability as well as mechanical property.