Melting of model structures: Molecular dynamics and Voronoi tessellation

Using classical molecular dynamics simulations combined with Voronoi tessellation we study the geometrical modifications as a function of temperature in two model Frank-Kasper phases: the A15 structure (beta-tungsten) and the cubic Friauf-Laves structure (MgCu2). We show how the perfect arrangement of disclination lines at 0 K for the crystalline structures evolves through the melting point. In particular, as the temperature is increased, the results permit us to identify the first defect and to show that the initial network of disclination lines survives until the solid-liquid first-order transition has indeed taken place.