Quasi-equilibrium and nonequilibrium explosive crystallization of InBi and In₂Bi compounds

The process of quasi-equilibrium and nonequilibrium explosive crystallizations of chemical compounds InBi and In₂Bi, as well as their components bismuth and indium, has been studied using cyclic thermal analysis (CTA) and differential thermal analysis (DTA). The experiments were carried out under the same conditions. It has been established that the chemical compound In₂Bi behaves like indium during crystallization, i.e., regardless of the preliminary overheating and the time of isothermal exposure of the melt to four hours, it crystallizes quasi-equilibriously with a slight pre-crystallization overcooling of 1.5-2 K. And the chemical compound InBi behaves like bismuth during crystallization. The temperature of critical overheating of the melt has been found, upon cooling from which crystallization has a quasi-equilibrium character (PK), and upon cooling from temperatures above, crystallization has an explosive character from the supercooled state, i.e., the dependence of melt overheating on overcooling is abrupt. The experimental results are interpreted from the point of view of the cluster-coagulation model of melt crystallization.