Influence of the interatomic repulsive hardness on the microstructure and dynamics of CuZr metallic glasses

The influence of the interatomic repulsive hardness (RH) on the microstructure and dynamics of CuZr metallic glass is studied by the molecular dynamics simulation method. By constructing potential energy functions that characterize different RH, we calculated their atomic diffusion coefficients, thermal expansion coefficients, radial distribution functions, fivefold symmetry order, and other related structural properties during the quenching process. We found that the atomic diffusion coefficients and thermal expansion coefficients decrease with RH, and the variation of radial distribution functions with temperatures becomes slower in softer RH. The softening RH is also accompanied by the enhancement of the icosahedral order in the liquids. Our results explain the experimental conclusion of "soft atoms make strong glasses" when considering the relation of the repulsive potential and liquid dynamics fragility.