Quantitative measurement of deformation field around low-angle grain boundaries by electron microscopy

The strain field of low-angle grain boundaries in gold was experimentally investigated. The grain boundaries consist of the arrangement of discrete dislocations. High-resolution transmission electron microscopy (HRTEM) and geometric phase analysis (GPA) were employed to map the strain field of grain boundaries. The numerical moiré method was used to visualize the dislocations. The strain components εxx, εyy, εxy and rigid rotation ωxy were mapped. The dislocation core regions are convergence regions of strain. The largest values of strain occur in the immediate dislocation core region. The strain field around an edge dislocation was compared with Peierls–Nabarro dislocation model. The comparison result has demonstrated that the Peierls–Nabarro model can describe the strain field around edge dislocation.