Grain Growth in Dynamically Recrystallized Copper During Annealing above and below the Temperature of Thermally Activated Nucleation

摘要

The effect of dynamic recrystallization on the change of the structure of copper (99.97 %), deformed by the "shear under pressure" and ECAP methods, during subsequent heating is studied. It is shown that different conditions of deformation of copper provide varying degrees of dynamic recrystallization, dynamic recovery and strain hardening. A submicrograin structure fails to be formed after primary recrystallization is completed. Dynamic recrystallization leads to the formation of the coarsest grain (15-20 μm) and size heterogeneous structure during subsequent recrystallization at 100 °C (below the temperature of thermally activated nucleation in moderately deformed copper). Heating at temperatures ranging between 150 °C and 400 °C (above the temperature of thermally activated nucleation) leads to the formation of finer grains in the fully recrystallized material. In samples with a partially dynamically recrystallized structure the grain size changes insignificantly. The finest grain with an average size of 4-7 μm is formed after short-time annealing at 300 °C.