Strain Resistivity at 4.2 K in Pure Aluminum
Strain induced resistivity increases are examined in pure aluminum under conditions of uniaxial tensile and compressive stress at 4.2 K. Metal studied has an annealed residual resistivity ratio (RRR = ρ273K/ρ4.2K^ covering the range 150 – 7100, is in some cases work hardened prior to testing, and is strained to levels below 10%. Resistivity is monitored during strain by eddy current coils located directly over strain gages bonded to centimeter diameter specimens. We find strain-resistivity to be slightly dependent on purity and similar for tension and compression. For all cases the empirical expression Ap = A (εp) holds for plastic strains (εp) above about 0.1% where A and B are constants. Values of B group around 1.5 for annealed metal and decrease to near 1.15 for the work hardened cases examined.
KeywordsPlastic Strain Strain Gage Pure Aluminum Empirical Expression Resistivity Increase
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- 1.G. T. Meaden, “Electrical Resistance of Metals,” Plenum Press, New York (1965).Google Scholar
- 2.V. D. Arp, M. B. Kasen, and R. P. Reed, “Magnetic Energy Storage and Cryogenic Aluminum Magnets,” Technical Report AFAPL-TR-68–87 (Feb. 1969).Google Scholar
- 4.“Superconducting Magnetic Energy Storage: Basic R&D,” EPRI Research Project RP2572–2 Annual Report (Jan. 1985).Google Scholar
- 6.A. F. Clark, V. A. Deason, J. G. Hust, and R. L. Powell, “Standard Reference Materials: The Eddy Current Decay Method for Resistivity Characterization of High Purity Metals,” NBS Special Publication 260–39, National Bureau of Standards, Boulder, Colorado (1972).Google Scholar