Electrical Resistivity Measurements: A Sensitive Tool for Studying Aluminium Alloys

Abstract

This paper examines the challenges which are encountered when using electrical resistivity measurements for characterization of microstructures in aluminum alloys. Experimental examples are provided of electrical resistivity studies conducted on two aluminum alloys, a heattreatable alloy (AA6111) and a non-heat-treatable alloy (AA5754), which demonstrate how the technique can be used to characterize changes in the microstructure. Results on AA6111 show that the dependence of the measurement on solute atoms and fine scale precipitates makes deconvolution of the resistivity signal non-trivial and therefore, utilization of supplementary technique(s) in conjunction with electrical resistivity measurements is essential. In the next example, room temperature electrical resistivity measurements as a function of cold work for AA5754 illustrate a larger resistivity contribution from dislocations in this alloy as compared to that reported for pure aluminum. The interaction of solutes and dislocations is cited as the possible source for the increased dislocation contribution.