Microstructural‐Mechanical Response and Mechanical Optimization of Steels: Insights From Dislocation‐Based Crystal Plasticity Finite Element Method Analysis of Grain Characteristics

Microstructure governs the mechanical properties of steel structures, and thus, predominantly influences their mechanical property. To gain an in‐depth understanding of this mechanism and to provide theoretical guidance for the manufacturing and optimization of steel structures, this article systematically investigates the interaction among grain characteristics, stress distribution, dislocation density, slip system activation, and tensile properties in steel structures using a dislocation‐based crystal plasticity finite element method. The results indicate that the tensile properties of a single crystal are governed by the peak internal stress, which is maximized at a grain orientation of ≈45° due to the activation of more slip systems. The mechanical performance of steels can be optimized through the synergistic effects of high‐angle grain boundaries (HAGBs) and favorable textures, with HAGBs providing local strengthening and advantageous textures improving strength and ductility. Grain refinement and bimodal grain size distribution enables a balance of strength and toughness, while increased grain equiaxiality enhances local stress concentration, dislocation accumulation, and tensile strength. Additionally, reducing inclusion size intensifies local reinforcement and further improves tensile properties. These findings can provide new perspectives and a solid theoretical foundation for optimizing and controlling mechanical performance in steel manufacturing, welding, and additive manufacturing processes.