Microstructure and mechanical properties of a TiAl-based powder alloy containing carbon

Gas-atomised powder of a Ti–48Al–2Mn–2Nb (at.%) matrix alloy containing 0.8 at.% carbon addition has been examined in the as-solidified and as-HIPped conditions. The as-atomised material consisted of fine powder particles supersaturated in carbon and coarser powder particles containing large carbide platelets. HIPping over the temperature range 1250–1400°C produced fully consolidated structures containing various carbide particles. Mechanical testing of HIPped samples revealed that carbon has a beneficial effect on the strength and creep behaviour, but reduces tensile ductility. The forgeability of the consolidated powder was also examined.