Microstructural evolution during non-isothermal annealing of a precipitation-hardenable aluminum alloy: Experiment and simulation

Microstructural evolution during non-isothermal annealing of a precipitation hardenable Al alloy is investigated experimentally, and simulated by developing a new Monte Carlo (MC) simulation technique. An annealing process that spans over a temperature range to promote the formation of a fine distribution of precipitates, is applied to a solution-treated Al-Mg-Si alloy. Experimental analysis of the deformed sample and samples non-isothermally annealed to intermediate temperatures reveals that early-stage precipitates inhibit dynamic recovery during deformation, as well as static recovery during the initial stages of annealing. Inhibition of recovery prior to the initiation of recrystallization leads to a high driving force for recrystallization and formation of randomly distributed recrystallized nuclei. Interactions of recovery, recrystallization and precipitations are integrated in the Monte Carlo algorithm and microstructural states during non-isothermal annealing are simulated. The MC technique is specifically designed for the systems in which precipitates inhibit dynamic recovery during the pre-annealing deformation stage. The good agreement achieved through comparison of MC simulation and experimental results supports the validity of the modeling technique developed.