Application of Disorder Trapping Theory to the Solidification of Ni₃Al

Abstract

A numerical analysis is presented of the solidification of compositions close to Ni₃Al. A two-sublattice thermodynamic model for the γ and γ' phases is combined with disorder trapping theory and dendrite growth modelling based on the marginal stability hypothesis. It is thereby possible to predict the composition and degree of order in the growing solid as a function of liquid composition and undercooling. Preliminary results are presented on solidification of the liquid of composition Ni-2at%Al.