Effect of nano-Y2O3 on microstructure and diffusive behavior of Ti3Al/Al3Ti matrix composite coatings

Laser cladding of the Al3Ti+TiC+(Ni-coated WC) pre-placed powders on titanium alloy can form the Ti3Al/Al3Ti matrix composite coating, which improves the surface performance of the substrate. With addition of nano-Y2O3, this composite coating exhibited a finer microstructure. In this study, the Al3Ti+TiC+(Ni-coated WC)+nano-Y2O3 laser-cladded coatings have been researched by means of X-ray diffraction and scanning electron microscope. The function of nano-Y2O3 acted as the heterogeneous nuclei, and the growth of the grains was hindered by Y2O3 and Y. Y2O3 can also decrease the temperature of the molten pool. Thus, the probability that grains traverse potential barrier decreased, leads to more stability of the grains.