KLIMOVÁ Alena

Spoluautoři GABALCOVÁ Zuzana, LAPIN Juraj

Quench during directional solidification (QDS) experiments and energy-dispersive spectrometry measurements were carried out to study the effect of growth rate V and temperature gradient in liquid at the solid-liquid interface GL on distribution of main alloying elements during solidification of the intermetallic Ti-44Al-5Nb-0.2B-0.2C (at%) alloy. Directional solidification was performed in a modified Bridgman-type apparatus in dense cylindrical Y2O3 moulds at three constant V and three constant GL. After directional solidification to a constant length the samples where quenched by a rapid displacement into the water-cooled crystallizer. For the qualitative and quantitative description of the distribution of the main alloying elements, the evolution of the concentration of Ti, Al and Nb as a function of the fraction solid fs and three segregation indexes for the studied elements - segregation range, segregation coefficient and segregation deviation parameter were evaluated. The studied alloy solidifies with β primary solidification phase and undergoes L + β → α peritectic transformation. The formation of peritectic α-phase affects back-diffusion of the alloying elements.

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