Analysis of the solidification microstructure of multi-component γ-TiAl alloys

Gamma titanium aluminide alloys often solidify peritectically and show a coarse, dendritic microstructure, which can lead to unacceptable mechanical properties in the as-cast condition. In view of the development of improved cast alloys, the dependence of the solidifying microstructure on the aluminum content and other alloying elements was investigated. The formation of the observed solidification microstructures is discussed in comparison with microstructure formation maps calculated by the NCU (nucleation and constitutional undercooling) model developed by Hunziker et al. [1].