Khacatrian A. Ab initio calculation of the characteristic parameters of quasi-binary eutectic boride composites

In the thesis by means of quantum-mechanical methods (a priori pseudopotential) calculated the characteristic parameters of the eutectic formation (concentration and melting temperature) for various quasi-binary ceramic matrix composites (based on borides and boron alloy). Under the proposed models are built pseudopotentials for polyatomic molecules with which calculated the energy of interaction between members of the composite. Using the pseudopotential method for alloys, built the thermodynamic potentials describing the state of the composites at zero temperatures. To calculate the temperature of the thermodynamic potentials used Einstein's model, where all the vibrating atoms is attributed to the same frequency. Obtain a functional dependence of the binary alloy thermodynamic potential from the component concentrations and temperature. Optimality conditions of thermodynamic potentials, a system of two algebraic equations with two unknowns - the concentration and temperature of the eutectic melting. Physical and mechanical properties of the composites were calculated using the law of mixtures. Calculated strength, Young's modulus of the composite, the coefficient of resistivity. The calculated Young's modulus values for the considered composites exceed their experimental values, as in the calculations are only considered ideal crystals, but, the general pattern of change of the Young's modulus for the material characteristic and the experimental data.