Synthesis and consolidation of TiAl by MA-PDS process from sponge-Ti and chip-Al

Low cost sponge-Ti and recycled chip-Al were used as starting materials for the synthesis and consolidation of TiAl alloy via a mechanical alloying (MA) and pulse discharge sintering (PDS) process. Amorphous structured TiAl powder was obtained by MA process from sponge-Ti/chip-Al and was sintered and concurrently consolidated with the PDS process. The obtained TiAl alloy consists of gamma-TiAl and alpha(2)-Ti3Al and additional Ti2AlC phase. The microstructure of the alloy can be controlled by the sintering temperature. It was found that fine equiaxed grains were obtained by low temperature sintering while fine duplex structures formed at high temperature sintering. Compared with alloys fabricated from high cost elemental Ti/Al powder with a similar process, the alloys sintered at high temperature with this process possess much higher strength at both room temperature and elevated temperatures. (C) 2003 Elsevier Science Ltd. All rights reserved.