DIFFUSION-CONTROLLED GROWTH IN TERNARY-SYSTEMS

Diffusion-controlled growth of particles, dendrites, and plates in inf inite media is examined for ternary systems. The growth kinetics assoc iated with planar, cylindrical, and spherical particles are shown to b e limiting cases of a more complete analysis (also presented) for shap e-preserving growth. The theory is applied to the growth of allotriomo rphic fenite from austenite in ternary Fe-C-X steels, where X represen ts a substitutional alloying element. Numerical results are given, the analysis relying on the ability to predict multicomponent phase equil ibria. The work represents an attempt at coupling together thermodynam ic and kinetic models for the diffusion-controlled phase transformatio ns that occur in steels.