Study on the microstructure of laser clad metallic silicide composite coatings on TiAl intermetallic alloy

γ-NiCrAl/Ti₅Si₃/TiSi composite coatings were fabricated on γ-TiAl intermetallic alloy by laser cladding pre-placed with NiCr-Si mixed powders. The microstructure of the laser clad metallic silicide composite coatings are characterized as function of constitution of the mixed precursor powders and their microstructural evolution process are discussed. The results show that microstructure of the laser clad composite coatings consists of primary blocky Ti₅Si₃ and dot-like γ/TiSi eutectics and is metallurgically bonded to the TiAl substrate. The volume fraction of the primary Ti₅Si₃ reinforced blocks and the microhardness of the laser clad composite coatings increases with the increasing of Si content in the mixed powder pre-coatings.