Microstructure and high temperature oxidation behavior of Ti-Al-Nb-Si coatings on Ti-6Al-4V alloy

Abstract Ti-Al- x Nb- y Si coatings were fabricated by laser surface alloying on a Ti-6Al-4V alloy substrate. The high-temperature oxidation behavior of the coatings was investigated at 800 °C. The coatings mainly consisted of TiAl x and Ti 5 Si 3 . Compared with the substrate and Ti-Al coatings, the Ti-Al- x Nb- y Si coatings showed better oxidation resistance. The synergistic effect of Nb and Si on improving high temperature oxidation resistance of the coatings included changing the control mechanism of the oxidation process, promoting the formation of Al 2 O 3 in the oxide scales, inhibiting the diffusion of oxygen and increasing the adhesion of the oxide scales.