A direct particle tracking model for predicting homogeneous precipitation kinetics in Al-Sc alloys

Abstract

The Kampmann-Wagner numerical (KWN) model, although been widely used in modeling the precipitation kinetics in solid solution alloys, has its own deficiency which is mainly reflected in two aspects: inability to track the growth history of individual particles and difficulty in describing the precipitation kinetics of non-spherical particles. In this work a direct particle tracking (DPT) model, which can well handle such issues, has been proposed and implemented. The main aim of this work is to check the validity and accuracy of the DPT model. To this end, the DPT model and two KWN models with different levels of accuracy have been applied to simulate the precipitation kinetics in two Al-Sc alloys. By comparing the numerical results with literature experimental data, it is found that the DPT model can well describe the microstructure evolutions during ageing of the Al-Sc alloys, and it has nearly the same accuracy as the KWN model with the governing equation solved by the high-resolution scheme (HR-KWN model). To reduce the amplitude of the oscillations formed in the particle size distribution (PSD) curves predicted by the DPT model, we need to set a small enough value for the time intervals divided in the nucleation stage.