Thermodynamic conditions of phase formation in Ti₃Al based alloys

Institute of Metal Physics, National Academy of Science, Ukraine Vernadsky pr 36, Kiev-180, Ukraine.

Abstract

In the titanium enriched part of Ti-Al diagram there were determined the temperatures of the beginning and of the end of phase transformation with the participation of liquid and solid β, α and α₂ -phases. Nonmonotonous character of fusible diagram and of the curves of ordering α→α₂ was established. The position of maximum at fusible diagram is determined, the most optimum for single crystal production there are the alloys, in which the composition corresponds to the maximums at the curves of L[math]β and α[math]α₂ phase transformations.

Résumé

Dans la partie du diagramme Ti-Al riche en titane, nous avous determine les temperatures de dibut et de fin des transformations de phases du liquide et des solides β, α et α₂. Le caractere non monotone du diagramme de fusibilité des liquides et des courbes d’ordre α[math]α₂ a ete etabli. La position du maximum du diagramme de fusibilité a été determinée.