On the room-temperature annealing of cryogenically rolled copper

The electron-backscatter-diffraction (EBSD) technique was applied to investigate room-temperature annealing processes in cryogenically rolled copper during long-term (∼1.5 years) storage at ambient temperature. Static recrystallization appeared to be nucleated as result of both grain-boundary bulging and recovery. A bimodal recrystallized grain size distribution appeared to be a result of these two competing mechanisms. The ultra-fine grain copper produced via cryogenic deformation was deduced to be prone to abnormal grain growth after long static storage at room-temperature.

► Cryo-rolled copper is unstable during long-term storage at room-temperature.
► Static recrystallization is nucleated via grain-boundary bulging and recovery.
► Two competing recrystallization mechanisms result in a bimodal grain structure.
► The specific nature of the recrystallization may induce abnormal grain growth.