DIFFUSION-CONTROLLED GROWTH IN TERNARY-SYSTEMS

Diffusion-controlled growth of particles, dendrites, and plates in infinite media is examined for ternary systems. The growth kinetics associated with planar, cylindrical, and spherical particles are shown to be limiting cases of a more complete analysis (also presented) for shape-preserving growth. The theory is applied to the growth of allotriomorphic fenite from austenite in ternary Fe-C-X steels, where X represents a substitutional alloying element. Numerical results are given, the analysis relying on the ability to predict multicomponent phase equilibria. The work represents an attempt at coupling together thermodynamic and kinetic models for the diffusion-controlled phase transformations that occur in steels.