Glass formation and crystallization of liquid and glass rubidium: A constant-pressure molecular-dynamics study

Abstract

Glass formation and crystallization processes in supercooled metallic liquid and the crystallization processes in glass are investigated for a rubidium system with 500 atoms by means of a constant-pressure molecular-dynamics technique. Calculations of thermodynamic and structural properties associated with the phase transitions are presented. The processes of structure transformation are analyzed by means of the atomic pair concepts, polyhedra, volume, energy, and pair distribution function. The results demonstrate a feature of structure transformation and show a clear picture of structure transitions during the cooling and heating processes. The glass formation has no sharp variations in the volume, the energy, or the structure, with temperature. However, the crystallization of both the supercooled liquid and the glass do have sharp variations. The results confirm that the transitions associated with these crystallization processes are first-order-like transitions, and that if there is a relaxation of the glass before the crystallization, the heating process which follows makes the glass more stable at low temperature. It is also confirmed that the cooling and heating rates have a strong effect on the transitions.