Effect of fine second phase particles on stored energy and recrystallization kinetics of cold rolled copper single crystals

Abstract

<mml:math><mml:mrow><mml:mo>(</mml:mo><mml:mn>111</mml:mn><mml:mo>)</mml:mo><mml:mo>[</mml:mo><mml:mn>1</mml:mn><mml:mover><mml:mn>1</mml:mn><mml:mi>¯</mml:mi></mml:mover><mml:mn>0</mml:mn><mml:mo>]</mml:mo></mml:mrow></mml:math> crystals of pure Cu–Al₂0₃ (particle size < 200 nm) have been strained between 5 and 204% by rolling. Stored energy measurements have been made by differential scanning calorimetry, and the recrystallization kinetics established. The stored energy of cold work is found to increase linearly with prior strain up to a saturation value. The presence of the second phase raises the stored energy by an amount proportional to the volume fraction of particles and also to the magnitude of the applied strain. Internal oxidation of pure Cu leads to the acceleration of recrystallization. Cu–Al₂0₃ crystals exhibit a change from suppressed to retarded to accelerated recrystallization as the strain is increased. To explain this a model based on nucleation at microbands is proposed.