Abnormal grain growth in thin copper foils during high-temperature annealing

We investigate grain growth at 1000 °C, a critical temperature for abnormal grain growth in copper foils. By ex-situ annealing experiments at 1000 °C, it is found that abnormal grains grow through the entire sample thickness, forming a polycrystalline structure with a single layer of grains. The migration of the boundaries surrounding the abnormally large grains are characterized by optical microscopy and electron backscatter diffraction. The migration rates are found to vary significantly from place to place, which is analysed based on boundary characteristics, i.e., misorientation and boundary curvature, and the size distribution of the neighbouring grains.