Abstract
A method for measuring specific resistivity after rolling was developed. Behaviors of dislocations, G.P. zones and transition phases in the high-purity Al-4.0 at%MgZn2 alloy thermomechanically treated were investigated. Dislocations ca. 1011/cm2 in density are introduced during cold rolling by 30% independently of pre-treatments. Room temperature aging may be initially accelerated in the alloy cold rolled immediately after quenching and is soon retarded. The final aging rate at 120°C is accelerated by cold rolling regardless of pre-treatments. Softening occurs at the start of final aging of the no pre-aging specimen probably due to recovery of cold rolled structures. Pre-aging at elevated tempera ture results in G.P. zones more stable and in an intensified accelerating effect of cold rolling on final aging. Resis-tivity and hardness after final aging of the alloy not rolled are increased by pre-aging. The increments are free from the change of pre-aging temperature.
