Evaluation of Temperature-Dependent Thermo-Plastic Behaviors of Single and Polycrystalline Pure Aluminum Based on Molecular Dynamics Simulation

Aluminum wire bonds in power semiconductor packages face high thermal loading, making finite element analysis (FEA) accuracy dependent on reliable temperature-dependent properties. Existing data often rely on discontinuous temperature points and overlook microstructural effects. This study proposes a Materials Studio-based molecular dynamics framework to evaluate the thermo-mechanical properties of pure aluminum using a Mishin EAM potential. Single-crystal and Voronoi polycrystalline models were constructed to analyze cell-size and grain-boundary effects. Following stepwise NVT/NPT equilibration, elastic constants were calculated via a small-strain method, and uniaxial tensile simulations were performed to derive Young’s modulus, Poisson’s ratio, linear thermal expansion coefficient, yield strength, and ultimate tensile strength across 238K to 498K. The single-crystal model revealed cell-size effects in post-peak deformation, while the polycrystalline model exhibited grain-boundary-induced softening at yielding but enhanced strength retention at ultimate tensile strength. Results were averaged and formulated into continuous regression functions. This approach supplements experimental data and provides continuous property inputs for power semiconductor FEA reliability analysis.