This study aims to represent the crystal structure of a manganese-based damping alloy by molecular dynamics (MD) simulation and to predict its mechanical properties, such as Young’s modulus and tensile strength, with high accuracy, without performing tensile and vibration tests. In the previous study, we developed a single-crystal MD model of the M2052 (Mn–20Cu–5Ni–2Fe) alloy and performed tensile test simulations. The simulation results indicate that the temperature dependence of Young’s modulus predicted by the single-crystal MD model follows the same trend as the experimental results. In this paper, we develop a polycrystalline MD model of the M2052 alloy incorporating twin boundaries and perform tensile test simulations to investigate the effect of grain size on its mechanical behavior. In particular, we focus on the relationship between grain size and yield stress to verify whether the Hall–Petch law holds for the microstructural model of the M2052 alloy. Using polycrystalline MD models with different grain sizes at 273 K, we determined the correlation between grain size and yield stress. The tensile test simulation results indicate that MD models with grain sizes of approximately 20 nm do not follow the Hall–Petch relationship.
FURUKAWA et al. (Wed,) studied this question.