Macroscale inhomogeneity in Zr-based bulk metallic glasses castings

Previous studies have demonstrated the presence of numerous microscale inhomogeneities within bulk metallic glasses (BMGs), yet the issue of macroscale inhomogeneities in castings remains largely overlooked. In this study, the phenomenon of macroscale inhomogeneity in Zr-based BMG castings is discovered, and its underlying thermodynamic and kinetic mechanisms are elucidated by molecular dynamics (MD) simulations. A direct correlation between the casting modulus and cooling times was established to classify different characteristic regions in BMGs castings. The region with the highest casting modulus hosts the most significant composition deviation from the initial nominal composition. Instead, regions with lower casting modulus show composition closest to the initial nominal composition. These results underscore the importance of controlling cooling conditions to optimize macroscale inhomogeneity in large-scale BMGs casting, providing valuable insights for improving their application in advanced engineering fields.