Atomistic simulation on stress barriers for dislocation transmission across <112> symmetric tilt grain boundaries in nickel

Understanding stress-governed dislocation interactions with symmetric tilt grain boundaries (GBs) is crucial for unraveling defect-dominated mechanical responses in face-centered cubic nickel. Through molecular dynamics simulations of both coincident site lattice GBs and general GBs with systematically varied misorientation angles ( θ ), we characterize three main interaction mechanisms between dislocations and tilt GBs: pile-up, absorption, and transmission. The dislocation-GB interaction dynamics demonstrate dual dependence on misorientation and applied stress: high-angle GBs ( θ ⩾ 45°) predominantly facilitate dislocation absorption under high-stress conditions or pile-up in low-stress regimes, whereas low-angle GBs ( θ < 45°) permit dislocation transmission upon exceeding critical stresses. Based on the resolved shear stress of slip system, a simplified correlation between critical transmission stress and misorientation θ is establish. Furthermore, the effect of local GB energy landscape characteristics is discussed. This work provides a predictive framework for tailoring interfacial plasticity in metal alloys.