Effects of grain size and mechanical pretreatment on strain localization in FCC polycrystals

K. Obergfell, Pedro Peralta, R. Martinez, J. R. Michael, L. Llanes, C. Laird

Research output: Contribution to journalArticle

4 Scopus citations

Abstract

Polycrystalline copper samples where the grains in the cross-section had crystallographic axes parallel to the load related to 'single slip' directions and three grain sizes, were ramp loaded and then step-tested to obtain their Cyclic Stress-Strain Curves (CSSCs). Plateaux were found for medium grain size at about 89 MPa, whereas large grained samples showed plateaux at 72 MPa, which correlated with the measured Taylor and Sachs factors, respectively. No plateaux were found when grains were smaller than 200 μm or ramp-loading stresses were below 87 MPa. Comparisons are made with nickel polycrystals and it is found that the plateaux in copper are narrower than those reported in nickel. The differences are attributed to a more homogeneous dislocation structure in nickel, due to lower elastic interactions across grain boundaries and easier cross-slip behavior as compared to copper.

Original languageEnglish (US)
Pages (from-to)207-214
Number of pages8
JournalInternational Journal of Fatigue
Volume23
Issue numberSUPPL. 1
DOIs
StatePublished - 2001

Keywords

  • Cyclic stress-strain curve
  • Dislocations
  • Grain size
  • Load histories
  • Strain localization

ASJC Scopus subject areas

  • Modeling and Simulation
  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering
  • Industrial and Manufacturing Engineering

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