Thermal stability of ECAP processed pure copper

Microstructure and texture evolution of pure copper (99.95%) after equal-channel angular pressing (ECAP) with route Bc up to 12 passes and subsequent heat treatment were investigated. After deformation the samples were annealed at different temperatures. The deformed and annealed states were characterized by X-ray pole figures, electron back scatter diffraction (EBSD), TEM and microhardness tests. It was shown that the observed texture and microstructure changes during subsequent annealing have to be associated with discontinuous recrystallization. The study revealed a very low thermal stability of this ECAP processed pure copper. The observed decrease of the apparent activation energy for recrystallization is most likely due to improved nucleation conditions of ECAP deformed material.