Al addition on the short and medium range order of CuZrAl metallic glasses

Appropriately addition of Al element can significantly enhance CuZr binary system mechanical properties and glass forming ability (GFA). In this work, the role of minor addition of Al atoms in CuZrAl metallic glasses is investigated by molecular dynamics (MD) simulation. The short and medium range structure of Cu50Zr50 and Cu45Zr50Al5 are systematically investigated from the liquid at 1600 K to amorphous solid at 100 K. Our results show that Al atoms tend to act as the centers of icosahedron (ICO), and it can remarkably increase the fraction of full ICO. More importantly, Al atoms can significantly facilitate the formation of Bergman medium range order, which accounts for the higher GFA of CuZrAl metallic glasses. The enhancement mechanism of Al addition on Bergman MRO can be explained by its adhesive effect on icosahedral clusters.