MELTING OF MODEL STRUCTURES - MOLECULAR-DYNAMICS AND VORONOI TESSELLATION

Using classical molecular dynamics simulations combined with Voronoi t essellation we study the geometrical modifications as a function of te mperature in two model Frank-Kasper phases: the A15 structure (beta-tu ngsten) and the cubic Friauf-Laves structure (MgCu2). We show how the perfect arrangement of disclination lines at 0 K for the crystalline s tructures evolves through the melting point. In particular, as the tem perature is increased, the results permit us to identify the first def ect and to show that the initial network of disclination lines survive s until the solid-liquid first-order transition has indeed taken place .