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Title:Yield behavior of niobium single crystals
Author(s):Huffaker, D.C.
Subject(s):Yield Behavior
Abstract:The yield behavior of niobium single crystals has been studied under conditions of different temperatures, strain rates, and microstructure. The effect of temperature and strain rate on the yield strength on the single crystal material investigated with <110> direction parallel to the compression axis seems to be characterized by the modified form of the rate process equation γ ̇ = Ae^(-(∆H* -V(τ- τ_i))/RT) where γ ̇ = Strain rate (resolved on the (110) plane and in the <111> direction) A = Frequency factor ∆H* = Activation energy at zero effective stress V = Activation volume τ = Observed stress (resolved on the (110) plane and in the <111> direction) τ_i = Internal (frictional) stress R = Universal gas constant T = Temperature, degrees Kelvin Within the range of variables studied the frequency factor has been found to be independent of stress, temperature and microstructure and has a value around 107/sec for the material investigated. The activation volume has been found to be dependent upon stress but independent of microstructure. The internal (frictional) stress has been shown to vary with the dislocation density as determined by etch pitting and optical microscopy. Furthermore, the frictional stress has been found to vary in an amount approximately proportional to the square root of the dislocation density.
Issue Date:1964-09
Publisher:Department of Theoretical and Applied Mechanics. College of Engineering. University of Illinois at Urbana-Champaign
Series/Report:TAM R 268
Genre:Technical Report
Sponsor:Atomic Energy Commission, Contract No. AT (11-1)-1046
Rights Information:Copyright 1964 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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