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Ti-Al based intermetallic alloys are promising for various applications in aerospace and automobile industry. Their favorable 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. fraction) alloy consists in change of their microstructure into lamellar microstructure, which can be reached moreover by directional crystallization. This experiment is described in this paper. Samples of the Ti-46Al-5Nb-1W (%,at. fraction) alloy prepared by plasma and vacuum-induction metallurgy were subjected to directional crystallization. Cooling rates were constant and ranged from 5.56×10~ -6 m/s to 1.18×10 ~ -4 m/s. Directional crystallization has been accomplished in ceramic tubes made of corundum-Al_ 2 O_ 3 . The samples were studied by metallographic and chemical analysis. Lamellar microstructure of the samples was found to consist of α_ 2 - and γ-phase lamellas. Moreover, ceramic particles Al_ 2 O_ 3 were found to be present in the samples. Distribution of the alloying elements in the samples was homogenous.
Ti-Al based intermetallic alloys are promising for various applications in aerospace and automobile industry. Their favorable properties, such as low low 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. fraction) alloy consists of change of their microstructure into lamellar microstructure, which can be reached moreover by directional crystallization. This experiment is described in this paper. Samples of the Ti- 46Al-5Nb-1W (%, at. Fraction) alloy prepared by plasma and vacuum-induction metallurgy were subjected to directional crystallization. Cooling rates were constant and ranged from 5.56 × 10 -6 m / s to 1.18 × 10 -4 m / s. Directional crystallization has been accomplished in ceramic tubes made of corundum-Al 2 O 3. The samples were studied by metallographic and chemical analysis. Lamellar microstructure of the samples was found to consist of α_ 2 - and γ-phase lamellas. Moreover, ceramic particles Al_2O_3 were found to be present in the samples. Distribution of the alloying elements in the samples was homogenous.