A model for the electrical conductivity of peak-aged and overaged Al-Zn-Mg-Cu alloys

Download

Preview	PDF (post-print: final draft post-refereeing in color) - Post print Download (2631Kb)
	PDF (Publisher version in b/w) - Publishers print Restricted to Registered users only Download (3086Kb) | Request a copy

Description/Abstract

A physically based model for the electrical conductivity of peak-aged and overaged Al-Zn-Mg-Cu (7xxx series) alloys is presented. The model includes calculations of the η- and the S-phase solvus (using a regular-solution model), taking account of the capillary effect and η coarsening. It takes account of the conductivity of grains (incorporating dissolved alloying elements, undissolved particles, and precipitates) and solute-depleted areas at the grain boundaries. Data from optical microscopy, differential scanning calorimetry (DSC), scanning electron microscopy (SEM) with energy-dispersive X-ray spectrometry (EDS), and transmission electron microscopy (TEM) are consistent with the model and its predictions. The model has been successfully used to fit and predict the conductivity data of a set of 7xxx alloys including both Zr-containing alloys and Cr-containing alloys under various aging conditions, achieving an accuracy of about 1 pct in predicting unseen conductivity data from this set of alloys.