Self-annealing and particle stimulated nucleation behavior of cryogenically rolled ETP-copper using 3D-EBSD

Abstract

In this study, electrolytic tough pitch copper (ETP-Cu) was subjected to cryogenic rolling up to 80 % deformation. Severe plastic deformation generated a high density of dislocations and increased stored energy, particularly around hard Cu2O particles, which significantly lowered the recrystallization temperature and promoted self-annealing. To elucidate the underlying mechanisms, 3D electron backscatter diffraction (3D-EBSD) combined with serial sectioning was employed to reconstruct the microstructure and analyze particle-stimulated nucleation (PSN) phenomena around Cu2O particles. The use of DREAM3D and ParaView enabled precise 3D visualization of recrystallized grains, particle-matrix interactions, and dislocation distributions. Results revealed that self-annealed grains predominantly exhibited equiaxed morphologies with an average volume of ∼0.23 μm3, while PSN occurred preferentially around Cu2O particles due to localized strain fields. Moreover, 3D-EBSD analysis confirmed that many recrystallized grains shared similar orientations, indicating continuous static recrystallization (CSRX) as the dominant mechanism. Discontinuous static recrystallization (DSRX) was also observed in a few grains that exhibited low KAM values. In contrast, CSRX grains near Cu2O particles showed higher KAM values. This study highlights the benefits of advanced 3D characterization techniques for elucidating Cu2O particle-induced nucleation during room-temperature annealing in cryogenically rolled ETP-Cu.