Formation of recrystallized grains at grain boundaries of copper bicrystals deformed in tension

Abstract

In order to clarify the formation mechanisms of recrystallized grains along grain boundaries, 99.99 mass% copper bicrystals were prepared using the modified Bridgman method. They were deformed in tension to the strain of 30-40% and annealed at certain conditions to get the early stage of primary recrystallization along the grain boundaries. The formation of recrystallized grains along the grain boundaries due to the strain induced boundary migration (SIBM) was observed, especially during the in situ observation by TEM. The formation of recrystallized grains due to the SIBM occurred along the grain boundaries with a high tilt component, toward which dislocations with large edge components piled up. The formation due to the 〈111〉 rotation mechanism occurred, on the other hand, along the grain boundaries with a high twist component, toward which dislocations with large screw components piled up. During the migration of the original grain boundaries many annealing twins were formed.