Precipitation sequences during quenching of the AA 7010 alloy

The precipitation sequences have been investigated during the cooling of an aluminium alloy AA 7010 from the solutionizing temperature. Interrupted quenching was performed at various temperatures and different holding times, The microstructure was then characterized at room temperature after the final fast cooling, using complementary experimental techniques. At high temperatures. the eta phase nucleates on dispersoids and grain boundaries. The composition, as well as the growth rate, of coarse intragranular precipitates are measured. At lower temperature (typically 250 degreesC), the solid solution decomposition promotes the precipitation of the 11 phase first, and then of the S and T phases. At low temperature, the precipitation of the eta' phase is observed. In this domain, the growth kinetics is followed. Those observations have been reported in a nucleation diagram. (C) 2002 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.