It is now well established that precipitation in age-hardenable aluminium alloys can be strongly influenced by deformation. Typically, deformation has an accelerating effect, which can be so powerful that similar levels of precipitation obtained after heat treatments over several hours can be achieved by deformation in minutes. However, the nature of the dynamic effect strongly depends on the conditions; in particular temperature and strain rate.

In this study, simple models have been used to explore dynamic precipitation effects for temperature and strain rate regimes that encompass commercially important processes in aluminium alloys. The effect of dynamic strain aging on dislocations, excess vacancies, and direct solute transport is discussed. At slow strain rate but elevated temperature, commercially important processes involving dynamic precipitation include the creep age forming process. Warm forming involves higher strain rates, and very high strain rates are encountered in friction stir and ultrasonic welding. In each case, the balance between dynamic mechanisms is investigated. The interplay between strain-rate and time is also discussed; high strain rate monotonic processes necessarily have shorter durations. It is demonstrated that there is an optimum window of strain rate and temperature where dynamic effects lead to the largest change in precipitate evolution. 

The implications of this in warm forming of age hardenable alloys is discussed, and a modelling framework that integrates dynamic precipitation effects into a crystal plasticity framework is introduced.