Annealing microstructural evolution and texture-stress-microstructure synergistic mechanism in electrodeposited nanocrystalline copper foil

Nanocrystalline materials have attracted attention due to their structure-property characteristics, but they are prone to coarsening at high temperatures due to dislocations and texture inhomogeneity. This study employed multi-scale characterization techniques (in-situ TEM, temperature-variable XRD, DSC, X-ray stress analysis) to systematically explore the annealing microstructure evolution mechanisms of electrodeposited nanocrystalline copper foil. Results reveal a 90°C critical temperature-induced (111)→(200) texture transformation, with low atomic diffusion activation energy (0.6118 eV·atom -1 ) facilitating structural rearrangement. Stress evolution is tightly coupled with texture change: the shift from low-temperature compressive to high-temperature tensile stress correlates directly with dominant texture transition and reduced anisotropy due to grain coarsening. In-situ observations confirm grain growth via Ostwald ripening, while nanotwin formation and annihilation are governed by defect dynamics and interfacial energy. Based on the regulatory mechanisms of defect dynamics and interfacial energy revealed in this study, the high-temperature service performance of electrodeposited nanocrystalline copper foil in microelectronic fields, such as electronic packaging and flexible circuits, can be significantly enhanced through the precise regulation of nanotwin interfacial energy and residual stress.