Abstract
	Intermetallic alloys based on ?-TiAl two-phases alloys are sought-after materials for assumed applications in aerospace and automotive industries. Their favourable properties, such as low density and good corrosion resistance, are accompanied on the other hand by low toughness and very difficult metallurgy. One of the possibilities to improve the toughness of Ti-46Al-5Nb-1W (at.%) alloy consists in change of their microstructure into lamellar microstructure, which can be reached moreover by directional crystallisation. This experiment is described in this paper. Samples of the Ti-46Al-5Nb-1W (at.%) alloy were prepared by plasma melting.  Then the samples were remelted in vacuum-induction furnace because of the low homogeneity. Cast samples were subjected to directional crystallization. Cooling rates were constant and ranged from 20 mm/h to 425 mm/h. Directional crystallization has been accomplished in ceramic tubes made of corundum – Al2O3. The samples were studied by metallographic analysis. Lamellar microstructure of the samples was found to consist of ?2- and ?-phase lamellas. Moreover, ceramic particles Al2O3 were found to be present in the samples. Distribution of the alloying elements in the samples was homogenous. Obtained lamellar microstructures are documented, contents of nitrogen and oxygen in dependence on parameters of crystallisation were verified and temperature of melting of this alloy was measured on DTA analyser.