Temperature and composition effects on the structure and mechanical behavior of V-Al metallic glasses

Metallic glasses (MGs) are amorphous alloys with high strength, elasticity, and corrosion resistance, making them attractive for diverse engineering applications. Unlike crystalline metals, their deformation is controlled by shear transformation zones, which are strongly influenced by short-range order (SRO) and medium-range order (MRO). Parameters such as potential energy, atomic volume, and five-fold symmetry have been linked to stability and plasticity, yet quantitatively connecting these atomic-scale features to macroscopic properties under varying conditions remains challenging. To address this, V-Al MGs were selected as a model system, given their potential for hydrogen storage and the ability to tune free volume through composition.

Molecular dynamics simulations were performed on V $_{80}^{}$ Al $_{20}^{}$ and V $_{50}^{}$ Al $_{50}^{}$ MGs to investigate structural and mechanical behavior. Potential energy, atomic volume, and five-fold symmetry, among others, were evaluated across SRO and MRO, while thermal effects were examined through atomic mobility and free volume. Tensile tests under uniaxial loading assessed stiffness, strength, and ductility. Results showed that the equiatomic alloy had higher potential energy, larger atomic volume, and reduced five-fold order, leading to lower strength but greater ductility. Temperature further decreased mechanical performance, with flow stress reductions up to 50%. Analytical models captured these trends, demonstrating compositional and thermal effects on structure-property relationships.