Semi-Empirical Kinetic Model for Phase Selection in Rapidly Solidified Multicomponent Concentrated Alloys
Abstract
A semi-empirical kinetic model is formulated for phase selection in multicomponent concentrated alloys under rapid-solidification conditions. The proposed approach is based on the critical cooling rate required to suppress competing crystallization pathways and combines topology-dependent ranking of crystallization pathways leading to BCC-, FCC-, and HCP-like structures with a correction accounting for glass-forming ability. The model includes a topology-dependent correction to the effective melt viscosity and a continuous glass-forming ability correction factor based on mixing enthalpy, excess entropy, and atomic-size mismatch. Comparison with experimental and computational data shows that the proposed kinetic phase-selection criterion identifies cases in which the kinetically preferred lattice type differs from that predicted by the valence electron concentration criterion, describes kinetic suppression of phase separation, and reveals competitive multiphase crystallization. The model also distinguishes between alloys with high and low glass-forming ability. The proposed model enables evaluation of kinetic competition between crystallization pathways and identification of the probable kinetically dominant pathway in rapidly solidified multicomponent alloys.