Numerical Simulation of Phase Transitions in Two-Component Materials upon Noncongruent Evaporation

The dynamics of noncongruent phase transitions in two-component materials upon evaporation in vacuum has been numerically simulated within a model based on the assumption of local thermodynamic equilibrium in the condensed phase. The results presented for nonstoichiometric uranium dioxide irradiated by a laser pulse have been obtained with allowance for the dependence of its thermodynamic and transport properties on the temperature and composition. It has been shown that, because of noncongruent evaporation changing the composition of the material in the surface region, its melting can begin in its interior even in the case of surface heating.