Study of the β"→ β' Transition in an Al-Mg-Si Alloy

Abstract

A detailed experimental study of the processes involved in the transition between the β” and β’ metastable phases in an Al-Mg-Si is presented. Measurements were performed by means of differential scanning calorimetry (DSC) and Vickers microhardness (Hv). A combination of isothermal and non-isothermal heat treatments, aimed to study the transition to β’ with different degrees of transformed fraction of β”, were applied.  Due to the proximity and overlapping of the events, the techniques of DSC and Hv for non-isothermal treatments were combined in order to obtain a better description. The obtained results were also related to the evolution observed for isothermal treatments, making the results independent of the heating rate. The results showed the presence of a dissolution in the transition β”→ β’, that this dissolution corresponds to the (at least partial) dissolution of the β” phase and that it is always present in the transition.