Solidification behaviour of TiAl-based alloys studied by directional solidification technique

Solidification behaviour of TiAl-based alloys with the nominal chemical composition Ti–46Al–8Ta and Ti–46Al–8Nb (at.%) was studied at steady- and unsteady-state conditions in Y₂O₃ moulds using Bridgman solidification technique. The effect of growth parameters (growth rate V and temperature gradient G_L) on primary solidification phase, solidification path and microstructure parameters were determined. Directional solidification at unsteady-state conditions was applied to determine columnar to equiaxed transition (CET) in the studied systems.