| Abstract Scope |
The mechanical properties of crystalline materials are strongly influenced by their dynamic responses to external stimuli such as temperature and stress. However, most atomic-scale studies have focused on static observations, leaving the mechanisms governing deformation and fracture insufficiently understood. To address this issue, we performed in-situ straining experiments in (S)TEM to directly visualize deformation and fracture in oxide and metallic materials. Bicrystals of SrTiO₃ and Al₂O₃ with well-defined grain boundaries, including coincidence-site lattice, low-angle tilt, and twist boundaries, were fabricated to investigate dislocation–grain boundary interactions. In addition, a newly developed MEMS-based straining holder enabled atomic-resolution observation of dislocation evolution in gold. These experiments directly revealed the formation and decomposition of Lomer–Cottrell and Lomer dislocations, providing new insight into the atomic mechanisms of work hardening and plastic deformation. The results demonstrate the unique capability of in-situ electron microscopy to clarify defect dynamics governing the mechanical behavior of crystalline materials. |