Investigating medium range order in Mg-Al binary metallic glasses: Molecular dynamics approach

Abstract

In this work, we used molecular dynamics (MD) simulations in order to investigate the Medium-Range Order (MRO) in Mg-Al binary metallic glasses (MGs). The embedded atom method (EAM) has been adopted to accurately model the interatomic interactions. Various techniques such as radial distribution function (RDF), coordination number (CN) analyses and Gaussian fitting have been mobilized to comprehensively study the impact of cooling rate, composition and mechanical solicitations, on the structural properties at the MRO level. Our results reveal that the 1-atom connection mode is consistently dominant across all cooling rates. Moreover, as the cooling rate increases in the Mg25Al75 binary MG, the abundance of the 4-atom and 2-atom connection modes increases, while the percentage of the 3-atom mode experiences a slight decrease. Furthermore, we investigate the influence of composition on the properties of MgxAl100-x alloys, demonstrating that the RDF peaks and connection modes are highly sensitive to variations in the Al concentration. Additionally, we explore the relationship between mechanical properties and connection modes during tensile deformation. The 3-atom connection mode exhibits superior hardness and stability, while the 4-atom and 2-atom connection modes offer increased flexibility. These significant findings enhance our understanding of MGs structural evolution, stability and deformation behavior. Ultimately, this knowledge facilitates the design and optimization of tailored MGs for advanced applications.