Effects of Si solute on the glass formation and atomic structure of Pd liquid

TL;DR

This study uses molecular dynamics simulations to show that small amounts of silicon doping improve the glass-forming ability of liquid palladium by promoting specific structural motifs and network formation.

Contribution

It demonstrates that Si solutes significantly enhance glass formation in Pd liquids, revealing the structural mechanisms behind this effect.

Findings

Si doping enables vitrification at lower cooling rates.

Dominant glass-forming motifs identified include Pd-centered Z13 and Si-centered Z9-like clusters.

Si-induced network structures correlate with increased glass-forming ability.

Abstract

Molecular dynamics simulations were performed to study the effects of Si solute on the glass formation and crystallization of Pd liquid. Pure Pd sample prepared by quenching process with cooling rate of $10^{13}$ K/s can be in an amorphous state but the structural analysis indicates there is nearly no glass-forming motif in the sample. However, doping a small amount Si (Si concentration ~ 4%) the sample can be vitrified at a cooling rate of $10^{12}$ K/s. The glass-forming motifs such as Pd-centered Z13, Si-centered Z9-like and Mixed-ICO-Cube clusters with 5-fold local symmetry are found to be the dominant short-range orders in the glassy samples. With the increasing of the Si-doping concentration, these glass-forming motifs tend to aggregate and connect with each other forming a network structure. Our calculated results revealed that Si solutes in liquid Pd can significantly enhance the glass-forming ability.