Deviations form Matthiessen’s Rule in Dilute Aluminum Alloys

Abstract

The electrical resistivity of dilute alloys of aluminum with Mg, Si, Cu, Zn and Ag as solute, respectively, has been measured together with the resistivity of pure aluminum from 4.2 to 300 K as a function of the solute concentration (0.001∼1 at%), to determine the deviation Δ from Matthiessen’s rule. At intermediate temperatures, the humps have been observed in the curves of Δ⁄ρ₀ (ρ₀: residual resistivity) versus temperature. The hump moves toward lower temperature and becomes more sharp and higher as the solute content decreases. These behaviors can be explained in terms of the anisotropy of the nonequilibrium electron distribution function. At lower temperatures, Δ does not follow a well defined Tⁿ law and it is attributed to simultaneous scattering by at least two processes. At high temperatures above about 100 K, Δ increases or decreases linearly with temperature.