Increased stability of CuZrAl metallic glasses prepared by physical vapor deposition

摘要

We carried out molecular dynamics simulations (MD) using realistic empiricalpotentials for the vapor deposition (VD) of CuZrAl glasses. VD glasses havehigher densities and lower potential and inherent structure energies than themelt-quenched glasses for the same alloys. The optimal substrate temperaturefor the deposition process is 0.625$\times T_\mathrm{g}$. In VD metallicglasses (MGs), the total number of icosahedral like clusters is higher than inthe melt-quenched MGs. Surprisingly, the VD glasses have a lower degree ofchemical mixing than the melt-quenched glasses. The reason for it is that themelt-quenched MGs can be viewed as frozen liquids, which means that theirchemical order is the same as in the liquid state. In contrast, during theformation of the VD MGs, the absence of the liquid state results in thecreation of a different chemical order with more Zr-Zr homonuclear bondscompared with the melt-quenched MGs. In order to obtain MGs from melt-quenchtechnique with similarly low energies as in the VD process, the cooling rateduring quenching would have to be many orders of magnitude lower than currentlyaccessible to MD simulations. The method proposed in this manuscript is a moreefficient way to create MGs by using MD simulations.