In-situ characterization of the dislocation-structure evolution in Ni micro-pillars

R. Maaß, M. D. Uchic

Research output: Contribution to journalArticle

Abstract

The high strength of micro-crystals is determined in the early flow regime, where a transition from elastic to plastic flow is obscured if compared to stress-strain data from bulk single crystals. In the present work we therefore focus on the evolution of dislocation structures in Ni micro-pillars during early deformation by employing in-situ Laue micro-diffraction. It will be shown that substantial changes in the lattice fine structure, such as multiple subgrain formation and significant rotational gradients, can be resolved prior to the onset of large strain generation. The results reveal more pronounced effects for smaller sample dimensions and also suggest that most of the evolving dislocation structure is formed prior to the occurrence of large strain bursts. A clear increase in dislocation density as a function of strain is observed, which we discuss in the context of size-dependent strain hardening and exhaustion hardening.

Original languageEnglish (US)
Pages (from-to)1027-1037
Number of pages11
JournalActa Materialia
Volume60
Issue number3
DOIs
StatePublished - Feb 1 2012
Externally publishedYes

Keywords

  • Micro-compression
  • Plastic deformation
  • Single crystal
  • Strain gradient
  • Strain hardening

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

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