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Void formation driven by plastic strain partitioning during creep deformation of WC-Co

Weller, L. ; M'saoubi, R. LU ; Giuliani, F. ; Humphry-Baker, S. and Marquardt, K. (2025) In International Journal of Refractory Metals and Hard Materials 126.
Abstract

Creep deformation of WC-Co composites at high temperature and stress is accommodated by either bulk WC creep or by Co-infiltrated grain boundary sliding. It has been proposed that certain grain boundaries are more susceptible than others to such sliding, and depending on the applied stress, the overall deformation rate can be limited by either mechanism. Here, we have used Electron Back-Scatter Diffraction to study the strain partitioning in each phase, the evolution in phase boundary and grain boundary misorientation, and void formation. Several WC-Co samples (Co contents ranging 7–13 % and grain sizes 0.5–1 μm) were deformed by unconstrained compression at 1000 °C under constant load in the range 0.5–1 GPa. The localised deformation... (More)

Creep deformation of WC-Co composites at high temperature and stress is accommodated by either bulk WC creep or by Co-infiltrated grain boundary sliding. It has been proposed that certain grain boundaries are more susceptible than others to such sliding, and depending on the applied stress, the overall deformation rate can be limited by either mechanism. Here, we have used Electron Back-Scatter Diffraction to study the strain partitioning in each phase, the evolution in phase boundary and grain boundary misorientation, and void formation. Several WC-Co samples (Co contents ranging 7–13 % and grain sizes 0.5–1 μm) were deformed by unconstrained compression at 1000 °C under constant load in the range 0.5–1 GPa. The localised deformation state – as characterised by increases in pixel misorientation and inverse pole figure dispersion – increased significantly between 0.5 and 0.75 GPa for both phases, which may be associated with the onset of grain boundary sliding. The onset of the formation of creep voids occurred when the stress level was 0.75 GPa or more. Deformation was correlated with an increase in 60° CoFCC /CoFCC boundaries, and in 56° WC/CoFCC boundaries. Boundaries with the latter misorientation angle may preferentially enable the Co infiltration process.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
EBSD, Hardmetals, High temperature creep, Tungsten carbide
in
International Journal of Refractory Metals and Hard Materials
volume
126
article number
106950
publisher
Elsevier
external identifiers
  • scopus:85208323803
ISSN
0263-4368
DOI
10.1016/j.ijrmhm.2024.106950
language
English
LU publication?
yes
id
94a9044e-d639-47e9-9fa5-ab4db3b55193
date added to LUP
2025-02-18 16:17:01
date last changed
2025-04-04 14:27:05
@article{94a9044e-d639-47e9-9fa5-ab4db3b55193,
  abstract     = {{<p>Creep deformation of WC-Co composites at high temperature and stress is accommodated by either bulk WC creep or by Co-infiltrated grain boundary sliding. It has been proposed that certain grain boundaries are more susceptible than others to such sliding, and depending on the applied stress, the overall deformation rate can be limited by either mechanism. Here, we have used Electron Back-Scatter Diffraction to study the strain partitioning in each phase, the evolution in phase boundary and grain boundary misorientation, and void formation. Several WC-Co samples (Co contents ranging 7–13 % and grain sizes 0.5–1 μm) were deformed by unconstrained compression at 1000 °C under constant load in the range 0.5–1 GPa. The localised deformation state – as characterised by increases in pixel misorientation and inverse pole figure dispersion – increased significantly between 0.5 and 0.75 GPa for both phases, which may be associated with the onset of grain boundary sliding. The onset of the formation of creep voids occurred when the stress level was 0.75 GPa or more. Deformation was correlated with an increase in 60° Co<sub>FCC</sub> /Co<sub>FCC</sub> boundaries, and in 56° WC/Co<sub>FCC</sub> boundaries. Boundaries with the latter misorientation angle may preferentially enable the Co infiltration process.</p>}},
  author       = {{Weller, L. and M'saoubi, R. and Giuliani, F. and Humphry-Baker, S. and Marquardt, K.}},
  issn         = {{0263-4368}},
  keywords     = {{EBSD; Hardmetals; High temperature creep; Tungsten carbide}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{International Journal of Refractory Metals and Hard Materials}},
  title        = {{Void formation driven by plastic strain partitioning during creep deformation of WC-Co}},
  url          = {{http://dx.doi.org/10.1016/j.ijrmhm.2024.106950}},
  doi          = {{10.1016/j.ijrmhm.2024.106950}},
  volume       = {{126}},
  year         = {{2025}},
}