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Ti-43Al-9V-Y alloy billets was prepared by the quasi-isothermal canned forging processing, and effect of heat treatment processes on the microstructure of as-forged Ti-43Al-9V-Y alloy was investigated. The results show that, as-forged Ti-43Al-9V-Y alloy has streamline microstructure including a large number of recrystallized grains and broken lamellae, and different heat treatment processes were employed to obtain different microstructures of Ti-43Al-9V-Y alloy. After heat treatment at 1250°C, the microstructure of as-forged Ti-43Al-9V-Y alloy becomes γ+B2 microstructure. Comparing with the microstructure after HT of 1250°C/30 min, the precipitation of B2 lath phase in γ equiaxed grains increased and γ grains refined after HT of 1280°C/30min or 1320°C/30min. However, after the heat treatment of 1300°C/30 min, the duplex microstructures can be gained.

This work deals with the consolidation of a TiAl alloy powder by spark plasma sintering (SPS). Pre-alloyed powder with a composition of Ti–48Al–2Cr–2Nb (at.%) was consolidated in a SPS furnace at temperatures between 1200${}^{\circ }$C and 1325${}^{\circ }$C and with a pressure of 50 MPa. The microstructures obtained after SPS depend on the sintering temperature. Tensile tests at room temperature were performed. The alloy SPSed at temperatures not less than 1250${}^{\circ }$C exhibits good properties at room temperature.

Atom packing structures of a large-angle tilt grain boundary between nano-grains in TiAl alloy are simulated at different temperatures by molecular dynamics simulations. Through the analysis of the average energy of the atoms and the atomic arrangements, these can be found that the atom packing in the grain boundary changes at different temperatures, there are different kinds of defects in the boundary and grain interior part, and Ti and Al atoms present different packing patterns.