Abstract
Recovery and recrystallization of a 90% cold rolled Al-0.2%Zr alloy were investigated by means of microscopic observation and hardeness measurement. Prior to cold rolling, four types of heat treatments, solution treatment, 1400 hour and 6500 hour aging at 350°C, and 4100 hour aging at 450°C were conducted. The experimental results are summarized as follows:
The recrystallization temperature was the highest in the aged specimens with particles of about 280 Å in diameter and the lowest in the aged specimens with incoherent globules. The letter specimens were softened slightly by lower temperature annealing.
The presence of Zr solute atoms in the matrix produced the pinning of dislocations during annealing and, thus, suppressed the effective movement of dislocations. Nucleation and growth rate significantly depended on the size of coherent spherical precipitates. Rod-shaped precipitates, formed by a grain boundary reaction, did not retard the recovery and recrystallization.
