Modelling of grain boundary segregation, precipitation and precipitate-free zones of high strength aluminium alloys—I. The model

Abstract

The earlier combined model [Faulkner and Jiang, Mater. Sci. Technol. 9, 665 (1993)] is improved by means of modifying the kinetics of segregation and taking into account the nucleation of grain boundary precipitates, the precipitate growth and coarsening. The newly developed model predicts the influence of the heat treatment on the widths of precipitate-free zones, the growth rate and the dispersion of the precipitates on the grain boundaries during the growth of precipitates. It also predicts the critical time when coarsening begins, the size and dispersion of precipitates on the grain boundaries during coarsening. The application of the model in predicting the size and inter-particle spacing of MgZn 2 grain boundary precipitate and the widths of precipitate-free zones in 7150 aluminium alloy as a function of heat treatment is discussed in Part I of this paper, and the comparison of the predicted and experimental results will be addressed in Part II.