Influence of Mg Si ratio on the clustering kinetics in Al Mg Si alloys

The clustering kinetics of Al amp; 9472;Mg amp; 9472;Si alloys is studied by means of differential scanning calorimetry. Five alloys with different Mg and Si contents from 0.4 to 1.1 at. are used. Two overlapping cluster peaks are observed in the heat flow curves; Cluster 1 C1 situated at amp; 61627;50 C and Cluster 2 C2 situated at around amp; 61627;80 C when heating at 10 Kmin 1. It was found that the heat effect of clustering is largest in alloys with Mg Si close to 1, while the C1 C2 heat effect ratio depends on the Si content. Activation energies for the two clustering processes C1 and C2 are obtained by applying different evaluation methods. The alloy having an Mg Si ratio close to 1 has the smallest initial activation energies for C1, while samples with higher Mg content have lower initial activation energies for C2, inferring that C1 is Si related, whereas C2 is Mg related. However, the entire clustering process requires both Mg and Si to procee