"Electrical conductivity measurements (eddy current determined) combined with indentation hardness measurements are now being used throughout the aerospace industry for nondestructive evaluation of the metallurgical condition of commercial precipitation hardenable aluminum alloys. The review of literature and experiments with two aluminum alloys, 7178 and a 5% Zn-Al binary, have shown that skilled interpretation of hardness-conductivity data depends not only upon a qualitative understanding of the modern wave mechanical theories of electron conduction, but also upon some knowledge of the precipitation reaction kinetics. In particular, the effects of "quenched-in" vacancies and retrogression upon the reaction kinetics must be considered. Studies of conductivity vs temperature in the range of 0 to 75⁰F show that the resulting conductivity changes do not result in increased interpretative information and the Matthiessen's rule and Hansen's equation both apply. Hansen's equation relates conductivity (K) of a sample to its temperature coefficient of resistance (α) in the form of K = Bα + C where B and C are constants. The values of B and C depend only upon the alloy system being considered. A practical result is that the conductivity for an unknown sample can be evaluated at any known ambient temperature and then corrected to its room temperature value by calculating the sample's coefficient of resistance using Hansen's equation. The inverse calculation could also be made"--Abstract, page ii.
Brasunas, Anton de S. (Anton de Sales)
Goben, C. A.
Branson, Donald Lee
Clark, J. B. (J. Beverley)
Materials Science and Engineering
M.S. in Metallurgical Engineering
University of Missouri at Rolla
vii, 84 pages
© 1967 Richard A. Mueller, All rights reserved.
Thesis - Open Access
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Mueller, Richard A., "Relationships among the metallurgical condition, hardness, and the electrical conductivity of aluminum alloys" (1967). Masters Theses. 6808.