Fine-grained nickel deformed by direct impact at different velocities: Microstructure and mechanical properties

G. Dirras, H. Couque, J. Gubicza, A. Ouarem, T. Chauveau, P. Jenei

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

High purity electrolytic nickel (99.99%) samples deformed dynamically in compression using a direct impact Hopkison pressure bar test at the velocities of 10.9, 28.2 and 70.6ms-1 were investigated. The dislocation density increased with increasing the impact velocity up to 28.2ms-1 resulting in an increase of nanohardness and quasi-static compressive flow stress. At the same time, a decrease of the fraction of Σ3 coincident site lattice boundaries was observed for the benefit of Σ1 low angle grain boundaries having misorientations lower than 15°. Increasing the velocity to 70.6ms-1 led to a decrease of the dislocation density, in parallel with the regeneration of Σ3 boundaries. As a consequence, the nanohardness decreased to a similar value as in the initial state. These observations suggest possible dynamic recovery/recrystallization that might have occurred at the highest impact velocity.

Original languageEnglish
Pages (from-to)4128-4135
Number of pages8
JournalMaterials Science and Engineering A
Volume527
Issue number16-17
DOIs
Publication statusPublished - Jun 1 2010

Keywords

  • Dynamic strain
  • Impact
  • Microstructure
  • Nickel
  • Recrystallization

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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