On the Influence of Stress and Strain on the Coarsening of Precipitates in Al-alloys under Creep Conditions

Two precipitation hardened Al alloys were studied. The coarsening behavior of metastable and coherent delta-prime precipitates of an Al-Mg-Li alloy was compared to that of an Al-Si-Ge alloy, which is hardened by stable and incoherent SiGe precipitates. Annealing experiments and interrupted creep tests were combined with fully quantitative TEM analysis. The relevant microstructural features of the precipitate population (volume fraction, number density, size distribution, etc.) were measured using quantitative image analysis techniques. (Author)