Comparative study of formation and transformation of transition phases in Al-12 wt.% Mg alloy

The use of various experimental techniques as differential dilatometry, differential scanning calorimetry, optical and transmission electron microscopy, internal friction, electrical resistance and microhardness measurements, shows their importance and their complementarity in the study of the ageing process in Al-12 wt.% Mg alloy. Indeed, their sensitivity to various precipitation stages is different and can give more information to describe the evolution of the structure, the nature and the morphology of the precipitated phases particles and the transition between them, which is not, yet, well established. The obtained dilatometric curves show numerous effects which have been discussed. During ageing of a supersaturated solid solution Al-12 wt.% Mg it seems that beta' and beta phases do not grow at the expense of GP zones (and/or beta ") and beta ', respectively. (C) 2001 Elsevier Science B.V. All rights reserved.