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

摘要

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 Y_2O_3 moulds using Bridgman solidification technique. The effect of growth parameters (growth rate V and temperature gradient Gl) 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.