Effect of Rare Earth Element (RE) Oxides on Diffusive Behaviour and Wear Resistance of a Laser Clad TiC/TiB_2 Reinforced Coating on a Ti-3Al-2V Alloy

摘要

TiC/TiB_2 reinforced composite coatings were fabricated by laser cladding of Al+Ni/Cr+B_4C+CeO_2 pre-placed powders on Ti-3Al-2V alloys. These composite coatings have been researched by means of X-ray diffraction (XRD) analysis, scanning electron microscope (SEM) and energy dispersive X-ray (EDX) analysis. The test results indicated that with addition of excessive CeO_2, the quality and wear resistance of this composite coating were poor. Moreover, excessive CeO_2 can also decrease the temperature of the molten pool, thus resulting in the weak diffusibility of Ti. With addition of proper CeO content, a large amount of Ti in the substrate were able to enter into the molten pool due to their high diffusibility, and this composite coating showed an excellent wear resistance and fine microstructure free of the pores and microcrack.