Study on microstructures and high temperature oxidation resistance of Ti-based NiAlSi alloy by laser cladding

The NiAlSi coating on Ti4 alloy surface was generated by laser cladding, the phase composition, microstructures, and oxidation resistance at 860 of the Ti℃ -based NiAlSi alloy were analyzed. The results show that, the fusion line is present at the interface of Ti4 ally and coating, which can be deduced that there is a good metallurgical combination between titanium alloy and coating. The numerous columnar crystals are formed in the coating bottom, and the major components of coating are composed of Ti₅Si₃ and Al₃Ni₂. The coating has higher oxidation resistance than titanium alloy. After high-temperature oxidation treatment for 40 h, the mass increase of coating is 2.19 mg·cm^-2, which is about 12 times higher than that of Ti4 alloy. After the oxidation treatment for 40 h at 860℃, the combination between coating and oxide film remains tied closely without peeling, and the main component of oxide film is Al₂O₃.