A molecular dynamics study on the liquid-amorphous-crystalline transition in a Lennard-Jonesian FCC system: I. bulk crystal

Constant-pressure molecular dynamics simulations are carried out to study the liquid-amorphous-crystalline transition behavior in a model system composed of 500 Lennard-Jones particles under three-dimensional periodic boundary conditions. The critical quenching rate (CQR) for amorphization, i.e., the minimum rate above which no crystallization occurs on quenching, is found to be about 5.52 x 1012 K/s for a one-component, unary system. For lower quenching rates, the amorphous phase transforms to a crystalline phase with 0.3~0.5 of the melting point as the transition temperature. A binary system with a misfit in atomic size shows a smaller CQR, while a system with a higher bond strength for solute atoms requires a greater CQR. A crystallization behavior of an amorphous phase on reheating is also studied. Its crystallization temperature depends on the history: the higher the quenching rate for amorphization, the higher the crystallization temperature.