Coupled Effects of Single-Vacancy Defect Positions on the Mechanical Properties and Electronic Structure of Aluminum Crystals

Vacancy defects, as fundamental disruptions in metallic lattices, play an important role in shaping the mechanical and electronic properties of aluminum crystals. However, the influence of vacancy position under coupled thermomechanical fields remains insufficiently understood. In this study, transmission and scanning electron microscopy were employed to observe dislocation structures and grain boundary heterogeneities in processed aluminum alloys, suggesting stress concentrations and microstructural inhomogeneities associated with vacancy accumulation. To complement these observations, first-principles calculations and molecular dynamics simulations were conducted for seven single-vacancy configurations in face-centered cubic aluminum. The stress response, total energy, density of states (DOS), and differential charge density were examined under varying compressive strain (ε = 0–0.1) and temperature (0–600 K). The results indicate that face-centered vacancies tend to reduce mechanical strength and perturb electronic states near the Fermi level, whereas corner and edge vacancies appear to have weaker effects. Elevated temperatures may partially restore electronic uniformity through thermal excitation. Overall, these findings suggest that vacancy position exerts a critical but position-dependent influence on coupled structure-property relationships, offering theoretical insights and preliminary experimental support for defect-engineered aluminum alloy design.