Continuous static recrystallization in ultrafine-grained copper processed by multi-directional forging

Annealing processes in copper, processed by multi-directional forging to strains of ɛ = 0.4–6.0 at 300 K, were studied at 503–573 K. Strain-induced ultrafine-grained copper shows mainly grain coarsening behaviour, which is categorized in three stages, i.e. (1) an incubation period, (2) a rapid and limited grain growth and finally (3) a classical (normal) grain growth. That is, in situ or continuous static recrystallization (cSRX) takes place in stages 1 and 2. The annealing characteristics and the mechanisms of cSRX are discussed with reference to those of conventional discontinuous SRX (dSRX).