Modeling and analysis of the structure of binary melts of the Ni-Mn system

Abstract

Structure models of Ni-Mn binary melts have been constructed using the Reverse Monte Carlo method and experimental curves of the structure factor. The local atomic structure has been analyzed employing the Voronoy-Delaunay statistical and geometrical method. It has been found that except for mathematical expectation and dispersion of the distribution of the sphericity coefficient of Voronoy polyhedra, concentration dependences of Ni-Mn melt structural parameters are of the additive nature. The analysis of the polyhedra metric characterization indicates that there occurs the dense noncrystalline packing of atoms in the melts under study, the portion of which increases with manganese concentration and reaches its maximum near the 66.7 Ni-33.3Mn melt. However, the melt that corresponds to the azeotropic point in the Ni-Mn phase diagram is characterized by an intensification of the interaction between the Ni-Mn and Mn-Mn pairs of atoms. This inhibits the formation of dense noncrystalline packing and increases the variety in the local surroundings of atoms of the melt at this point.