Atomic-level diffusion at the amorphous Zr50Cu50/crystalline Cu interface: A molecular dynamics study

Abstract

The interdiffusion and atomic structure of the interface between metallic glass Cu50Zr50 and crystalline Cu were investigated using molecular dynamics simulations. We show that the interdiffusion of atoms at the amorphous/crystalline interface is mainly manifested as the diffusion of crystalline Cu atoms into amorphous atoms, and only a very small amount of amorphous atoms diffuse into crystalline Cu. And the temperature and diffusion time are proportional to the thickness of the diffusion layer. The H-A bond index and Voronoi polyhedron distribution method were used to analyze the structure type and cluster distribution of the interface atoms. the results show that the diffusion will cause the amorphization of the atoms on the crystal side of the interface, and the higher the temperature and the longer the diffusion time, the higher the degree of amorphization of the interface atoms. And the size of the amorphized region is related to the temperature, and the dividing plane between the amorphized atoms and the crystal atoms gradually moves to the crystal side with the increase of temperature. In addition, the diffusion behavior of atoms at the amorphous/crystal interface with different crystal orientations exhibits anisotropy, and some atoms at the interface between the 〈110〉 oriented crystal and amorphous are transformed from FCC structure to HCP structure during the diffusion process.

Keywords

• Molecular dynamics
• Interfacial diffusion
• Atomic structure
• Zrr-Cu amorphous