Dissolution of β particles in an AlMgSi alloy during DSC runs

Abstract

A DSC experimental study of the dissolution kinetics of β precipitates in an AlMgSi alloy has been carried out in order to test the validity of a recent particle dissolution model [F.J. Vermolen, K. Vuik, S. van der Zwaag, Mater. Sci. Eng. A246 (1998) 93–103; F.J. Vermolen, K. Vuik, S. van der Zwaag, Mater. Sci. Eng. A254 (1998) 13–32; F.J. Vermolen, Ph.D Thesis, Delft University, Press, The Netherlands]. The results demonstrate that the model is successful in simulating particle dissolution during linear heating. The concentrations of both alloying elements at the particle–matrix interface during particle dissolution are decided by both the solubility product and the diffusion coefficients. The existence of a size distribution of particles was found to have a significant effect on the dissolution kinetics and therefore should be included in any model if an accurate prediction of the dissolution kinetics is to be achieved.