Abstract
This study systematically explores the structural stability, mechanical properties, elastic anisotropy, fracture toughness, and thermophysical characteristics of Au(3)In and Au(3)In(2) intermetallic compounds (IMCs) through density functional theory (DFT) simulations. Employing the generalized gradient approximation (GGA) and the Voigt-Reuss-Hill approximation enables precise predictions of polycrystalline elastic behavior, providing critical insights into the intrinsic stability and mechanical anisotropy of these IMCs. Structural optimization identifies the equilibrium lattice parameters and cohesive energies, indicating stronger atomic bonding and superior structural stability in Au(3)In relative to Au(3)In(2). Elastic constant calculations confirm mechanical stability and reveal pronounced anisotropic elastic behavior; Au(3)In exhibits significant stiffness along the [010] crystallographic direction, while Au(3)In(2) demonstrates notable stiffness predominantly along the [001] direction. Both Au(3)In and Au(3)In(2) exhibit ductile characteristics, confirmed by positive Cauchy pressures and elevated bulk-to-shear modulus (K/G) ratios. Fracture toughness analysis further establishes that Au(3)In offers greater resistance to crack propagation compared to Au(3)In(2), suggesting its suitability in mechanically demanding applications. Thermophysical property evaluations demonstrate that Au(3)In possesses higher thermal conductivity, elevated Debye temperature, and superior volumetric heat capacity relative to Au(3)In(2), reflecting its enhanced capability for effective thermal management in electronic packaging. Anisotropy assessments, utilizing both universal and Zener anisotropy indices, reveal significantly higher mechanical anisotropy in Au(3)In(2), influencing its practical applicability.