Behavior of amorphous materials under hydrostatic pressures: A molecular dynamics simulation study

The atomic structural behavior of amorphous pure Ni under hydrostatic pressures has been investigated through a molecular dynamics simulation study based on a semi-empirical interatomic potential (MEAM). It was observed that the amorphous material crystallizes under hydrostatic compressive pressur e but forms nanovoids under hydrostatic tensile pressure at room temperature. These results could be explained by the volume change effect on the nucleation energy barrier during crystallization. Consistent with this explanation, stress induced increase in the energy level (decrease of energy barrier) is proposed as the main reason for the mechanically driven nanocrystallization of amorphous materials.