First-principles kinetic theory of precipitate evolution in Al-Zn alloys

The time evolution of the distribution of precipitate shapes and sizes in Al-Zn alloys is studied via a mixed-space cluster expansion and kinetic Monte-Carlo simulations. We find that the growth of precipitates in Al-rich Al-Zn alloys follows classical Ostwald ripening already after ageing times of a few seconds. Moreover, the distribution of the precipitates is temperature-dependent: the higher the ageing temperature, the smaller the distribution width of the precipitate size. We discuss the time evolution of the precipitates in terms of short-range order parameters and compare them with experimental data.