Molecular Dynamics Study of Crystallization Behavior in the Solid State of Zr-Cu Amorphous Alloys

Abstract

Amorphous alloys show interesting mechanical properties as well as unique physical and chemical properties due to their atomic stacking structure. However, when partial crystallization occurs in amorphous alloys, it can impact the properties of the original amorphous alloy. To study the crystallization phenomenon in the Zr-based amorphous alloy, a three-dimensional Zr-based amorphous alloy atomic-stacking model was established by molecular dynamics simulations, and the atomic structure evolution of the Zr-Cu amorphous system after partial crystallization was analyzed by the radial distribution function g(r), HA bond index and Voronoi polyhedron. The results showed that adding more copper (Cu) atoms to the Zr-Cu amorphous system greatly improves its stability at high temperatures. The atomic diffusion was analyzed by root-mean-square displacement of atoms (MSD); as the temperature rose, the MSD of atoms also increased, suggesting that the crystallization of the amorphous material occurs due to the short-range diffusion of atoms. The analysis of the mechanism of the high-temperature action time on the Zr80Cu20 amorphous alloy showed that the crystallization phase precipitation rate of the amorphous alloy gradually increases with time, but it does not change linearly.