Room temperature deformation mechanisms in ultrafine-grained materials processed by hot isostatic pressing

W. Q. Cao, G. F. Dirras, M. Benyoucef , B. Bacroix

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23 Citations (Scopus)

Abstract

Ultrafine-grained (uf-g) and microcrystalline-grained (mc-g) irons have been fabricated by hot isostatic pressing of nanopowders. The mechanical properties have been characterized by compressive tests at room temperature and the resulting microstructures and textures have been determined by combining electron back scatter diffraction and transmission electron microscopy. A transition of the deformation mode, from work hardening to work softening occurs for grain sizes below ∼1 μm, reflecting a transition of the deformation mode from homogeneous to localized deformation into shear bands (SBs). The homogeneous deformation is found to be lattice dislocation-based while the deformation within SBs involves lattice dislocations as well as boundary-related mechanisms, possibly grain boundary sliding accommodated by boundary opening. 

Original languageEnglish
Pages (from-to)100-105
Number of pages6
JournalMaterials Science and Engineering A: Structural Materials: Properties, Microstructure and Processing
Volume462
Issue number1-2
DOIs
Publication statusPublished - 25 Jul 2007

Keywords

  • Boundary sliding
  • Deformation mechanism
  • Hot isostatic pressing
  • Iron
  • Mechanical properties
  • Ultrafine grains

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