Zheng, LJ (reprint author), Beijing Univ Aeronaut & Astronaut, Sch Mat Sci & Engn, Beijing 100083, Peoples R China.
The precipitate size, distribution and volume fraction in an AlZnMgCu-1.0 wt.% Li alloys during various aging conditions were investigated by small-angle X-ray scattering and transmission electron microscopy. According to the selected area diffraction patterns, the prime precipitates in this alloy are eta' phases, not delta' phases. During the temperature ranging from 120 to 160 degreesC, the growing of precipitates in the 7055-1.0 wt.% alloy is not apparent. From 120 to 150 degreesC, the varieties of precipitate volume fraction depend on the competition between dissolution rate of GP zones and nucleation rate of eta'. At 160 degreesC, the growing of eta' precipitates is undergoing a Lifshitz-Slyozov-Wagner coarsening process, and the prime thermodynamic reaction is the nucleation growth of eta' precipitates. (C) 2003 Elsevier Science B.V. All rights reserved.