STRUCTURE OF G. P. ZONE IN Al-Mg_2Si ALLOYS

摘要

The existence of G.P. zone in Al-Mg-Si alloys have been reported by previous workers using X-ray diffraction method or DSC method. The structure of the G.P. zone in an Al-1.6mass%Mg_2Si alloy aged at 343 and 423K was investigated by high resolution transmission electron microscopy in this work. The morphology of the G.P. zone is fine-plate having dimensions of a mono-layer in thickness, 2.5nm in width and less than 30nm in length. Its elongated direction is parallel to the <100>m direction. The chemical composition of the G.P. zone in an Al-Mg_2Si alloy was determined to be Mg/Si=l .0.