Mapping dislocation densities resulting from severe plastic deformation using large strain machining

Sepideh Abolghasem, Saurabh Basu, Shashank Shekhar, M. Ravi Shankar

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


The multiplication of dislocations determines the trajectories of microstructure evolution during plastic deformation. It has been recognized that the dislocation storage and the deformation-driven subgrain formation are correlated - the principle of similitude, where the dislocation density (ρi) scales self-similarly with the subgrain size (δ): ∼ constant. Here, the robustness of this concept in Cu is probed utilizing large strain machining across a swathe of severe shear deformation conditions - strains in the range 1-10 and strain-rates 10-103/s. Deformation strain, strain-rate, and temperature characterizations are juxtaposed with electron microscopy, and dislocation densities are measured by quantification of broadening of X-ray diffraction peaks of crystallographic planes. We parameterize the variation of dislocation density as a function of strain and a rate parameter R, a function of strain-rate, temperature, and material constants. We confirm the preservation of similitude between dislocation density and the subgrain structure across orders-of-magnitude of thermomechanical conditions.

Original languageEnglish (US)
Pages (from-to)3762-3773
Number of pages12
JournalJournal of Materials Research
Issue number22
StatePublished - Nov 28 2018

All Science Journal Classification (ASJC) codes

  • General Materials Science
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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