Modeling the strengthening response to aging process of heat-treatable aluminum alloys containing plate/disc- or rod/needle-shaped precipitates

For the heat-treatable aluminum alloys containing plate or rod/needle-shaped precipitates, a previous model was modified to present quantitative relationships between the yield strengths of the alloys and the sizes, volume percentages of precipitates, related to aging temperature and aging time as well as alloy compositions, while the strengthening of the precipitates was coupled with the whole evolution process, i.e. nucleation, growth and coarsening, of the precipitates. It was found that the aging yield strengths have been well predicted by the model for a series of aged Al-Cu binary alloys, 6061 alloys and Al-Zn-Mg alloys. It was also experimentally proved that the model was suitable to evaluate the aging strengthening of the precipitates for an Al-Cu-Mg alloy and an Al-Mg-Si alloy. Furthermore, a detailed discussion has been made to the variation of aspect ratio of precipitates, relative to its strengthening response, with aging parameters and alloy compositions. (C) 2002 Published by Elsevier Science B.V.