Elevated Temperature Compression Behavior of Al–Cu₅₀Zr₅₀ Nano-laminates

Abstract

In this work, molecular dynamics simulation studies are performed to investigate the deformation behavior of Al (metal)–Cu₅₀Zr₅₀ (metallic glass) nano-laminates. Three-layer nano-laminate models have been used for compression studies in which Cu₅₀Zr₅₀ metallic glass (thickness = 34 Å) is a sandwich layer between the two Al layers (33 Å thick). Al is modeled as a single crystal and polycrystal (average grain size ~ 3.5 nm). The deformation studies have been carried out by subjecting the nano-laminates to compression loading (y-axis; periodic boundary) at a strain rate of 10¹⁰ s⁻¹ and temperatures of 400 K and 500 K. The simulation results show that the nano-laminate with Al as a polycrystalline structure exhibits higher yield strength as compared to the nano-laminate with Al as a single crystal [σ_{Al,Polycrystal} = 0.376 GPa (400 K); σ_{Al,single crystal} = 0.272 GPa (400 K); σ_{Al,Polycrystal} = 0.152 GPa (500 K); σ_{Al,single crystal} = 0.129 GPa (500 K)]. The higher strength is attributed to the low dislocation density as observed from dislocation extraction algorithm analysis. Also, the flow stress decreases with temperature due to softening as expected.