Daniel Larouche¹, Tohid Naseri¹, Rémi Martinez², Francis Breton³, Denis Massinon⁴; ¹Laval University, ²Linamar Corporation, ³Rio Tinto, ⁴Montupet Laigneville

One of the major difficulties encountered in the modelling of aging in multicomponent alloys is to reproduce accurately the sequence of precipitation with the proper incubation time for each phase. This is especially difficult when many hardening phases are involved because of the number of parameters that have to be accounted for by the traditional nucleation and growth theories. The concept that nucleation is a two-step process including a subcritical growth regime can be used when the nucleation sites are activated right after the quench, which simplify the modelling to the growth rates of the precipitates. In this contribution, a growth and dissolution model including the effect of the interfacial mobility will be used to simulate the precipitation kinetics of Mg-Si precipitates in a ternary Al-Mg-Si alloy. It will be shown that the interfacial mobility of the different phases can explain the precipitation sequence in a very efficient and convincing way.