Subgrain structure and dislocations in WC-Co hard metals revealed by electron channelling contrast imaging

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Abstract

In this study, electron channelling contrast imaging (ECCI) and electron backscatter diffraction (EBSD) have been used to examine the substructure and dislocations in tungsten carbide (WC) grains in tungsten carbide-cobalt (WC-Co) hardmetals. These complimentary scanning electron microscopy (SEM) diffraction techniques provide quantifiable information of the substructure without the difficulty of transmission electron microscopy (TEM) sample preparation and examination. Subgrain structures in WC grains have rarely been reported previously because of the sample preparation difficulty, but this study has found they can occur frequently and may provide information on grain growth during sintering. ECCI has also shown for the first time complex dislocation networks across large grains, indicating accumulation of stress in as-sintered materials. To identify the defects revealed by ECCI more precisely, WC grains with surface normals [0001],[1-100] and [11-20], were identified using inverse pole figure orientation maps generated from EBSD data. ECC images from these grains reveal defects intersecting the surface and subgrains bound by dislocations. The combination of ECCI and EBSD allows for new insights into dislocation networks in a WC-Co hardmetal sample over a large, in this case 75 μm × 75 μm, field of view.
Original languageEnglish
Article number105159
Number of pages18
JournalInternational Journal of Refractory Metals and Hard Materials
Volume87
Early online date15 Nov 2019
DOIs
Publication statusE-pub ahead of print - 15 Nov 2019

Fingerprint

tungsten carbides
Tungsten carbide
Cobalt
cobalt
Imaging techniques
Electrons
Metals
Electron diffraction
metals
electrons
substructures
diffraction
Defects
preparation
Grain growth
defects
tungsten carbide
hard metal
Poles
Sintering

Keywords

  • hardmetal
  • subgrain
  • dislocations
  • ECCI
  • EBSD
  • WC

Cite this

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title = "Subgrain structure and dislocations in WC-Co hard metals revealed by electron channelling contrast imaging",
abstract = "In this study, electron channelling contrast imaging (ECCI) and electron backscatter diffraction (EBSD) have been used to examine the substructure and dislocations in tungsten carbide (WC) grains in tungsten carbide-cobalt (WC-Co) hardmetals. These complimentary scanning electron microscopy (SEM) diffraction techniques provide quantifiable information of the substructure without the difficulty of transmission electron microscopy (TEM) sample preparation and examination. Subgrain structures in WC grains have rarely been reported previously because of the sample preparation difficulty, but this study has found they can occur frequently and may provide information on grain growth during sintering. ECCI has also shown for the first time complex dislocation networks across large grains, indicating accumulation of stress in as-sintered materials. To identify the defects revealed by ECCI more precisely, WC grains with surface normals [0001],[1-100] and [11-20], were identified using inverse pole figure orientation maps generated from EBSD data. ECC images from these grains reveal defects intersecting the surface and subgrains bound by dislocations. The combination of ECCI and EBSD allows for new insights into dislocation networks in a WC-Co hardmetal sample over a large, in this case 75 μm × 75 μm, field of view.",
keywords = "hardmetal, subgrain, dislocations, ECCI, EBSD, WC",
author = "B.M. Jablon and K. Mingard and A. Winkelmann and G. Naresh-Kumar and B. Hourahine and C. Trager-Cowan",
year = "2019",
month = "11",
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doi = "10.1016/j.ijrmhm.2019.105159",
language = "English",
volume = "87",
journal = "International Journal of Refractory Metals and Hard Materials",
issn = "0263-4368",

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TY - JOUR

T1 - Subgrain structure and dislocations in WC-Co hard metals revealed by electron channelling contrast imaging

AU - Jablon, B.M.

AU - Mingard, K.

AU - Winkelmann, A.

AU - Naresh-Kumar, G.

AU - Hourahine, B.

AU - Trager-Cowan, C.

PY - 2019/11/15

Y1 - 2019/11/15

N2 - In this study, electron channelling contrast imaging (ECCI) and electron backscatter diffraction (EBSD) have been used to examine the substructure and dislocations in tungsten carbide (WC) grains in tungsten carbide-cobalt (WC-Co) hardmetals. These complimentary scanning electron microscopy (SEM) diffraction techniques provide quantifiable information of the substructure without the difficulty of transmission electron microscopy (TEM) sample preparation and examination. Subgrain structures in WC grains have rarely been reported previously because of the sample preparation difficulty, but this study has found they can occur frequently and may provide information on grain growth during sintering. ECCI has also shown for the first time complex dislocation networks across large grains, indicating accumulation of stress in as-sintered materials. To identify the defects revealed by ECCI more precisely, WC grains with surface normals [0001],[1-100] and [11-20], were identified using inverse pole figure orientation maps generated from EBSD data. ECC images from these grains reveal defects intersecting the surface and subgrains bound by dislocations. The combination of ECCI and EBSD allows for new insights into dislocation networks in a WC-Co hardmetal sample over a large, in this case 75 μm × 75 μm, field of view.

AB - In this study, electron channelling contrast imaging (ECCI) and electron backscatter diffraction (EBSD) have been used to examine the substructure and dislocations in tungsten carbide (WC) grains in tungsten carbide-cobalt (WC-Co) hardmetals. These complimentary scanning electron microscopy (SEM) diffraction techniques provide quantifiable information of the substructure without the difficulty of transmission electron microscopy (TEM) sample preparation and examination. Subgrain structures in WC grains have rarely been reported previously because of the sample preparation difficulty, but this study has found they can occur frequently and may provide information on grain growth during sintering. ECCI has also shown for the first time complex dislocation networks across large grains, indicating accumulation of stress in as-sintered materials. To identify the defects revealed by ECCI more precisely, WC grains with surface normals [0001],[1-100] and [11-20], were identified using inverse pole figure orientation maps generated from EBSD data. ECC images from these grains reveal defects intersecting the surface and subgrains bound by dislocations. The combination of ECCI and EBSD allows for new insights into dislocation networks in a WC-Co hardmetal sample over a large, in this case 75 μm × 75 μm, field of view.

KW - hardmetal

KW - subgrain

KW - dislocations

KW - ECCI

KW - EBSD

KW - WC

UR - https://www.sciencedirect.com/journal/international-journal-of-refractory-metals-and-hard-materials

U2 - 10.1016/j.ijrmhm.2019.105159

DO - 10.1016/j.ijrmhm.2019.105159

M3 - Article

VL - 87

JO - International Journal of Refractory Metals and Hard Materials

JF - International Journal of Refractory Metals and Hard Materials

SN - 0263-4368

M1 - 105159

ER -