Dependence of hardening and saturation stress in persistent slip bands on strain amplitude during cyclic fatigue loading

C. Erel, G. Po, N. Ghoniem

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

Cyclic loading of FCC single crystals leads to the formation of persistent slip bands (PSBs) over a wide range of applied strain amplitudes. The hardening and saturation stress associated with cyclic loading of Cu single crystals are reproduced with 3-D discrete dislocation dynamics simulations. Evolution of the dislocation microstructure in PSB channels and walls during cyclic loading is shown to explain key features of plastic deformation. Screw dislocation segments are found to deposit edge components near PSB channel walls resulting in the nucleation of half-loops that expand into neighbouring channels. The saturation stress is found to be (Formula presented.) 34 MPa at an applied strain amplitude, (Formula presented.), within the range of experimental observations. It is shown that once PSBs are formed, subsequent cycling at lower strain amplitudes does not lead to their elimination, but the cyclic stress–strain behaviour is modified. At lower values of (Formula presented.) of previously formed PSBs, the saturation stress is found to decrease to (Formula presented.) 24 MPa at (Formula presented.). Plastic energy dissipation in hysteresis loops is also significantly reduced but not removed. However, some reverse plasticity is shown to take place upon unloading at low values of (Formula presented.), and is a direct result of strain recovery of loops that expand into neighbouring channels during the loading phase.

Original languageEnglish (US)
Pages (from-to)2947-2970
Number of pages24
JournalPhilosophical Magazine
Volume97
Issue number32
DOIs
StatePublished - Nov 12 2017
Externally publishedYes

Keywords

  • cyclic hardening
  • Dislocation dynamics
  • fatigue
  • FCC
  • persistent slip band
  • saturation stress

ASJC Scopus subject areas

  • Condensed Matter Physics

Fingerprint

Dive into the research topics of 'Dependence of hardening and saturation stress in persistent slip bands on strain amplitude during cyclic fatigue loading'. Together they form a unique fingerprint.

Cite this