Atomistic mechanisms for temperature-induced crystallization of amorphous copper based on molecular dynamics simulation

Abstract

Atomistic mechanisms for temperature-induced crystallization of amorphous copper were investigated by means of molecular dynamics (MD) simulation. During the crystallization, three kinds of atom structures are formed, where face-centered cubic (FCC) structure is dominant, and body-centered cubic (BCC) structure possesses the lowest fraction. The crystallization of amorphous copper is a process of atom diffusion, where atoms in an unstable state are activated by the heat energy and then they diffuse to the locations in which their energy is minimum. During the diffusion, BCC structure is initially formed in the amorphous copper because it possesses a larger volume. As a consequence, both the close-packed hexagonal (HCP) structure and the FCC structure are transformed from the BCC structure. The crystallization of amorphous copper results in plenty of dislocations, which are formed through two approaches. The first approach is the plastic slip induced by the thermal stress, which may be aroused by the thermal-expansion coefficient difference between the crystallized atoms and the amorphous ones. The second approach is the phase transformation, which refers to the transformation from HCP structure to FCC structure in the present study.