Size distribution and coarsening kinetics of δ′ precipitates in Al-Li alloys considering temperature and concentration dependence

While the aging temperature is increased to low undercooling, 180degreesC for Al-9.7 at.% Li alloy, the transitions of both the coarsening mechanism and the size distribution of delta' precipitates in Al-Li alloy are found and studied using small-angle X-ray scattering (SAXS) technique. A modified precipitation mechanism considering this transition is explored with respect to both the determined precipitate size distribution and the growth rate constant. Additionally, a more adequate method is established for estimating the growth rate constant as a function of aging temperature and Li concentration, and those results are compared with corresponding measurement results. (C) 2003 Elsevier B.V. All rights reserved.