Unveiling a medium-range structural commonality of amorphous alloys

• Published in: Journal of non-crystalline solids 2024-01, Vol.624, p.122696, Article 122696
• Main Authors: Nishio, Kengo, Lu, Anh Khoa Augustin
• Format: Article
• Language: English
• Subjects: Fivefold twin; Glass structure; Laves phases; Medium-range order; Molecular dynamics simulation
• ISSN: 0022-3093; 1873-4812
• DOI: 10.1016/j.jnoncrysol.2023.122696

Despite their complex atomic arrangements, previous investigations have uncovered structural features common to various metallic glasses such as dense cluster packings, local icosahedral symmetry or docosahedral clusters. While this has contributed to unraveling the nature of metallic glasses, our understanding of structural commonalities in general remains limited. In this study, we unveil a common structural feature associated with Laves phases by examining two model alloys that can adopt Laves phases. Our molecular dynamics simulations show that glasses made with sufficiently slow cooling rates contain medium-range structures resembling the core of a fivefold twinned crystal that consists of five structural units of MgCu2-type Laves structure. Since Laves phases are commonly found in Cr-, Cu-, Fe-, Mg-, Nb-, Ni-, Ti-, and Zr-based alloys, these medium-range pentagonal structures are expected to be found in a wide range of amorphous materials. •Glasses of two model alloys that can adopt Laves phases are studied using molecular dynamics simulations.•Glasses made with sufficiently slow cooling rates contain medium-range structures resembling the core of a fivefold twinned crystal that consists of five structural units of MgCu2-type Laves structure.•The medium-range pentagonal structures unveiled in this work are expected to be found in a wide range of amorphous materials, for Laves phases are present in systems such as Cr-, Cu-, Fe-, Mg-, Nb-, Ni-, Ti-, and Zr-based alloys, as well as colloidal mixtures.