Investigation of deformation micro-mechanisms in nickel consolidated from a bimodal powder by spark plasma sintering

D. Tingaud, P. Jenei, A. Krawczynska, F. Mompiou, J. Gubicza, G. Dirras

Research output: Article

11 Citations (Scopus)

Abstract

Bulk polycrystalline nickel compact was processed by spark plasma sintering from heterogeneous powder consisting of a mixture of nanometer and micrometer sized particles. The consolidated samples inherited the bimodal structure of the starting powder and was composed of ∼55 vol.% coarse-grained (with the grain size larger than 1 innodatamum) and ∼45 vol.% ultrafine-grained (with an average grain size of ∼550 nm) components. The deformation mechanisms were established by EBSD, X-ray line pro file analysis and in-situ TEM observations. In the ultrafine-grained volume, the deformation occurred mainly through the activation of dislocation sources emitting full or partial dislocation either from grain interior or grain boundaries. Besides dislocation activity, rolling and sliding of nanograins were also observed during deformation by in-situ transmission electron microscopy, which have a considerable contribution to the observed high strain rate sensitivity of the bimodal microstructure. The cracks formed during deformation easily propagated in the nanograin regions due to the weaker particle bonding caused by the relatively high fraction of native oxide layer on the surface of the initial nanoparticles.

Original languageEnglish
Pages (from-to)118-127
Number of pages10
JournalMaterials Characterization
Volume99
DOIs
Publication statusPublished - 2015

Fingerprint

Spark plasma sintering
sparks
Nickel
Powders
sintering
nickel
Dislocations (crystals)
grain size
Transmission electron microscopy
transmission electron microscopy
files
Oxides
strain rate
sliding
micrometers
Strain rate
Grain boundaries
cracks
grain boundaries
Chemical activation

ASJC Scopus subject areas

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

Cite this

Investigation of deformation micro-mechanisms in nickel consolidated from a bimodal powder by spark plasma sintering. / Tingaud, D.; Jenei, P.; Krawczynska, A.; Mompiou, F.; Gubicza, J.; Dirras, G.

In: Materials Characterization, Vol. 99, 2015, p. 118-127.

Research output: Article

Tingaud, D. ; Jenei, P. ; Krawczynska, A. ; Mompiou, F. ; Gubicza, J. ; Dirras, G. / Investigation of deformation micro-mechanisms in nickel consolidated from a bimodal powder by spark plasma sintering. In: Materials Characterization. 2015 ; Vol. 99. pp. 118-127.
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AU - Gubicza, J.

AU - Dirras, G.

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