Preferential nucleation of dynamic recrystallization at triple junctions

The preferential nucleation of dynamic recrystallization (DRX) was investigated in copper polycrystals deformed in compression at 873K and a true strain rate of 2.9 · 10 � 4 s � 1 . DRX nucleation started preferentially at triple junctions (TJs) at strains of 0.02– 0.04, while the peak strain in the flow curve was about 0.08. The number of DRX nuclei at the TJs increased linearly with strain. At a strain of 0.04, DRX was initiated at about 40% of the TJs. However, nucleation was difficult when the TJ contained a twin boundary. It was also noted that most of the nuclei possessed a twin (R3) relation with respect to its parent grain. This is one of the essential features of discontinuous DRX in copper. DRX nucleation at TJs and twin formation are discussed in relation to grainboundary sliding, grain-boundary migration, and misorientation angle. � 2003Published by Elsevier Ltd. on behalf of Acta Materialia Inc.