Transition of deformation mechanism with grain refinement in interstitial-free steel

Shun Itoh, Kasane Nakazawa, Tetsuya Matsunaga, Yoshitaka Matsukawa, Yuhki Satoh, Hiroaki Abe

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


To examine effects of the grain boundary (GB) and dislocation on the deformation mechanism for ultrafine-grained (UFG) and coarse-grained (CG) interstitial-free (IF) steels at room temperature, tensile tests and several types of microscopy were conducted for each steel. Atomic force microscopy revealed that the contribution of grain-boundary sliding (GBS) on deformation increased more prominently in UFG region than in CG region. Moreover, transmission electron microscopy revealed that dislocation motion was dominant in CG steel, where cell structure was formed with increasing strain. On the other hand, although dislocations moved in UFG steel, they did not tangle and piled up at GB, where interaction between GB and dislocation occurred markedly, causing significant GBS. Therefore, the dominant deformation mechanism changed from dislocation motion to GBS by decreasing grain size in IF steel.

Original languageEnglish
Pages (from-to)1729-1734
Number of pages6
JournalIsij International
Issue number7
Publication statusPublished - 2014


  • Atomic force microscopy
  • Dislocation structure
  • Grain-boundary sliding
  • Interstitial-free steel
  • Ultrafine-grain

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry


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