Effect of Rare Earth Element (RE) Oxides on Diffusive Behaviour and Wear Resistance of a Laser Clad TiC/TiB2 Reinforced Coating on a Ti-3Al-2V Alloy
P. Liu, H-X. Li and Y-B. Zhang
TiC/TiB2 reinforced composite coatings were fabricated by laser cladding of Al+Ni/Cr+B4C+CeO2 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 CeO2, the quality and wear resistance of this composite coating were poor. Moreover, excessive CeO2 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.
Keywords: Rare earth element (RE), laser cladding, CO2 laser, TiC/TiB2, Ti-3Al-2V, diffusive behaviour