Atomic-scale simulations of the interfacial mechanical properties of Al/AlCu intermetallic compounds

The dynamic evolution and the mechanical properties of Al-Cu interfacial microstructures hold considerable scientific and technological significance. This study explores the mechanical behavior of Al/AlCu intermetallic compound (IMC) layered composites using the NEP machine learning molecular dynamics simulation method, with a focus on the bond strength between the Al matrix and various AlCu alloy interfaces. The Al/Al₂Cu/Al and Al/Al₄Cu₉/Al composite systems exhibit significantly enhanced bond strength, resulting in an overall improvement in their mechanical properties. The ordered atomic arrangement of Al-Cu at the interface effectively regulates stress distribution. Notably, the strength of θ'-Al₂Cu is found to increase by approximately 30% compared to the pure polycrystalline Al system. In contrast, the Al₃Cu IMC interface results in reduced bond strength between the Al matrix and the interface due to its poor structural stability, leading to a larger damage region at the grain boundary-Al₃Cu interface. Under high-strain-rate conditions, the Al₂Cu IMC interface is compressed by the polycrystalline Al along the <i>z</i>-direction, leading to greater distortion at the interface.