Deviations from matthiessen's rule in deformed and annealed Al-Mg alloys

Electrical resistivities of pure Al-3,7 and 10 at. per cent Mg and commercial 5052, measured in heavily deformed and annealed states between 1 and 60 K, are tabulated. Previously, studies were for Mg concentrations below 1.75 at. per cent only. For temperatures above 40 K data are sufficiently precise to show that the established total resistivity equation also describes deviations for the higher Mg concentrations, and that the deviations are substantially the same in deformed and well-annealed samples of the same residual resistivity rhoo, and the ideal resistivity was calculated using the Gruneisen-Bloch formula. The (rho-rhoo) data at 50 and 60 K plotted are in good agreement with the log rhoo dependence; this result is consistent with recent theories. The variation of delta with an increase in rhoo due to dislocations is comparable to or smaller than the variation due to Mg defects. This is consistent with results of Holzhauser on pure Al. 13 ref.--EPAA/AF.