Investigation on microstructure characteristics of Ti-48Al alloy fabricated using twin-wire directed energy deposition-plasma arc

Ti-48Al alloy is fabricated successfully using plasma arc powred twin wire-directed energy deposition-arc, and its microstructure characteristic before and after heat treatment is systematically investigated. The results show that as-deposited Ti-48Al alloy consists of α₂ and γ phase. The microstructure is characterized by the alternatively distributed dendritic grain and fully lamellar colony along the building direction for as-deposited Ti-48Al alloy, and there is interdendritic Al element segregation in the dendritic grain region. After heat treatment in 1340 ℃/10 h/furnace cooling, the duplex microstructure with fine grain size is obtained, and the microstructure heterogeneity is significantly improved, the α₂ phase content is obviously increased, the preferred orientation of microstructure is also weakened.