Computer simulation of phases consisting of Be, B and Li atoms and calculating their elastic properties using quantum mechanical calculation

Chemical elements of groups 1 and 2 have the most pronounced properties in their periods. There is something unique about each of them, inciting substantial interest, especially regarding light-weight alloys of these elements. Young's modulus to density ratio of beryllium is six times higher than that of steel. Heat-resistance of Be is 600°C. The combination of these physicochemical properties makes beryllium alloys specifically applicable in aerospace. Simulation of material properties is one of the main missions for materials science. Elastic properties are the easiest to calculate compared to other mechanical properties. Elastic properties are characterized by the fifth-fourth digits of the total cluster energy. Here we present the results of the calculation of the elastic constants of hexagonal and cubic beryllium and cubic lithium boride. The calculations were based on the density functional theory (DFT). The results obtained by different techniques (quantum chemical, semi-empirical) and data from the literature were compared. (paper)