Ultrafine Grain Evolution in Copper Alloys Induced by Mechanisms of Continuous Dynamic and Static Recrystallization

摘要

Ultrafine grained (UFGed) structure was uniformly evolved in a Cu-1.7mass%Fe alloy by the repeated cycles of thermo-mechanical processes (TMPs) of ⅰ) warm compression and annealing, and ⅱ) cold rolling and low temperature annealing. The UFGs possessed a slightly elongated shape of aspect ratio of 2 because of strong pinning effect boundaries by the Fe precipitates. The minimum grain size was about 0.7 μm. The UFG evolution was confirmed caused by recovery, i.e., continuous dynamic and continuous static recrystallizations. The repeated cycles of TMPs increased grain boundary misorientation angle gradually. Fe precipitates played an important role on substucture evolution as nodes of the dislocation networks and grain boundaries. The occurrence of discontinuous static and dynamic recrystallizations caused grain coarsening.