Modelling dynamic precipitation in pre-aged aluminium alloys under warm forming conditions

This work presents a model for deformation enhanced precipitate growth and coarsening kinetics in pre-aged 7xxx aluminium alloys under warm forming conditions (100 to 200 °C). A multi-class Kampmann–Wagner framework is used to describe the evolution of precipitate size distribution, where the effect of deformation is incorporated through enhanced solute diffusivity resulting from deformation induced excess vacancies. A classical phenomenological model is used to describe the accumulation of excess vacancies. The model is validated with experimental warm deformation data from the literature, and applied to investigate a wide range of deformation conditions to predict the effect of strain, strain rate and temperature on precipitate growth and coarsening kinetics. It is demonstrated that the interaction of solute supersaturation and excess vacancy concentration can lead to complex non-monotonic precipitate growth rate variation for certain regimes of strain rate and temperature.