Recovery kinetics in Al-0.3%Cu after heavy rolling

The recovery kinetics of a nanoscale lamellar structure Al-0.3%Cu alloy, which was produced by 98% cold rolling, during annealing at temperatures from 100 to 200 degrees C have been analyzed in this study. Microstructural characterization using electron channelling contrast in the scanning electron microscope shows a uniform coarsening of the lamellar structure and gradual precipitation of second phase particles (Al2Cu) during annealing at these temperatures. Fitting of the microhardness values for samples annealed for between 4 and 4096 minutes at different temperatures with a recovery model reveals a change, in the apparent activation energy from 79 kJ/mol at the beginning to 105 kJ/mol at the end of recovery annealing, which leads to a discussion of the recovery mechanisms.