Effect of Precipitates on the Development of P Orientation {011}\( \left\langle {566} \right\rangle \) in a Recrystallized Continuous Cast AA 3004 Aluminum Alloy after Cold Rolling

The as-received hot band (2.54-mm thick) of a continuous cast (CC) AA 3004 Al alloy was cold rolled at reductions, ranging from 25 to 90 pct, and subsequently annealed at 510 °C for 4 hours. Some of these specimens had been annealed at 420 °C for 3 hours with a heating rate of 1 °C/min prior to cold rolling. It was found that the sample with the prior heat treatment exhibited a P orientation ({011}\( \left\langle {566} \right\rangle \)) of 28 pct in volume fraction, stronger than that (23 pct) in the sample without the prior heat treatment, after 90 pct cold rolling and final recrystallization. The transmission electron microscopy (TEM) observations revealed that the prior heat treatment generated very densely distributed Al₆(Mn,Fe) precipitates, which could pin dislocations and grain boundaries in the alloy. The formation of stronger P texture in the sample with the prior heat treatment revealed that the P texture could also be developed due to dislocations pinned by the existing fine Al₆(Mn,Fe) precipitates during recrystallization in the CC Al alloys that contained Mn.