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Title:Cyclic hardening and softening effects in polycrystalline copper
Author(s):Metropole, Sonia Reva Kronick
Subject(s):Polycrystalline Copper
Cyclic Hardening
Cyclic Softening
Abstract:Cyclic torsion was imposed upon specimens of copper tubing in order to ascertain whether or not a saturation flow stress could be attained in the metal after a finite number of strain cycles were applied. Variables introduced into the test procedure were strain amplitude, temperature, and number of strain cycles. The constants were frequency of cycling and initial structure of the metal. A consistent pattern of behavior was found to prevail throughout the course of testing. Cyclic hardening or softening occurred as the strain amplitude was increased or decreased, respectively. The number of cycles required to produce a change in stress level depended upon the amplitude of the alternating strain. Dependence of stress upon temperature was also determined. From the results obtained during the investigation, it was decided that a limiting stress value was attained after a finite number of strain cycles were applied to the specimens. The two main external factors influencing the material's behavior were strain amplitude and temperature. The effect of the strain amplitude in changing the stress was most prominent during the early cycles of straining, however, that recovery effects due to thermal activation occurred throughout the entire test. The influence of temperature upon the stress variation was small compared to that of the srain amplitude. On the basis of the test results, expressions were developed to relate temperature, strain amplitude, and number of strain cycles with stress.
Issue Date:1965-06
Publisher:Department of Theoretical and Applied Mechanics. College of Engineering. University of Illinois at Urbana-Champaign
Series/Report:TAM R 655
Genre:Technical Report
Sponsor:Air Force Materials Lab Wright Patterson AFB Ohio 65/06
Rights Information:Copyright 1965 Board of Trustees of the University of Illinois
Date Available in IDEALS:2021-11-04

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  • Technical Reports - Theoretical and Applied Mechanics (TAM)
    TAM technical reports include manuscripts intended for publication, theses judged to have general interest, notes prepared for short courses, symposia compiled from outstanding undergraduate projects, and reports prepared for research-sponsoring agencies.

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