Clustering in Al-Zn-Mg Alloys

Abstract

The change of resistivity during isothermal aging after quenching were measured in Al–10wt%Zn–0.13wt% Mg and Al–10wt%Zn–0.3wt%Mg alloys. General features of clustering in these alloys were different from those in binary Al–10wt%Zn alloy. Small increase of resistivity occured before main increase of resistivity due to clustering of Zn atoms. This small increase of resistivity was attributed to clustering of both Mg and Zn atoms into G. P. zones which were diffrent from those in binary Al–Zn alloys. Time required to reach maximum of resistivity in these alloys was much longer than those in binary alloys. it was deduced that this fact did not depend upon large binding energy between an Mg atom and a vacancy but might be due to interaction between G. P. zones containing both Mg and Zn atoms and vacancies.