Corrosion damage in WC–Co cemented carbides: residual strength assessment and 3D FIB-FESEM tomography characterisation

Tarragó, J.M.; Fargas, Gemma; Jiménez‐Piqué, E.; Felip, Alba; Isern, Luis; Coureaux, D.; Roa, J.J.; Al-Dawery, I.; Fair, J.; Llanes, L.

doi:10.1179/1743290114y.0000000115

Cited by 26 publications

(32 citation statements)

References 29 publications

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“…Refs. [39,56,57]), and its strength is intimately associated with nature, size and geometry of such defects [2]. In this regard, one beneficial aspect of materials exhibiting R-curve behavior is that effective toughness level rises as the size of the flaw also increases [21].…”

Section: Analytical Assessment Of R-curve Behavior: Toughening Mechanicsmentioning

confidence: 99%

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FIB/FESEM experimental and analytical assessment of R-curve behavior of WC–Co cemented carbides

Tarragó

Jiménez‐Piqué

Schneider

et al. 2015

Materials Science and Engineering: A

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Exceptional fracture toughness levels exhibited by WC-Co cemented carbides (hardmetals) are due mainly to toughening derived from plastic stretching of crack-bridging ductile enclaves. This takes place due to the development of a multiligament zone at the wake of cracks growing in a stable manner. As a result, hardmetals exhibit crack growth resistance (R-curve) behavior.In this work, the toughening mechanics and mechanisms of these materials are investigated by combining experimental and analytical approaches. Focused Ion Beam technique (FIB) and Field-Emission Scanning Electron Microscopy (FESEM) are implemented to obtain serial sectioning and imaging of crack-microstructure interaction in cracks arrested after stable extension under monotonic loading. The micrographs obtained provide experimental proof of the developing multiligament zone, including failure micromechanisms within individual bridging ligaments. Analytical assessment of the multiligament zone is then conducted on the basis of experimental information attained from FIB/FESEM images, and a model for the description of R-curve behavior of hardmetals is proposed. It was found that, due to the large stresses supported by the highly constrained and strongly bonded bridging ligaments, WC-Co cemented carbides exhibit quite steep but short R-curve behavior. Relevant strength and reliability attributes exhibited by hardmetals may then be rationalized on the basis of such toughening scenario.

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Section: Analytical Assessment Of R-curve Behavior: Toughening Mechanicsmentioning

confidence: 99%

“…Refs. [15,38,39]). For these reasons, the aim of this study is to investigate the fracture behavior of WC-Co cemented carbides by documenting and analyzing toughening phenomena through serial FIB sectioning and field emission scanning electron microscopy (FESEM) imaging.…”

Section: Introductionmentioning

confidence: 99%

FIB/FESEM experimental and analytical assessment of R-curve behavior of WC–Co cemented carbides

Tarragó

Jiménez‐Piqué

Schneider

et al. 2015

Materials Science and Engineering: A

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“…Refs. [7][8][9]). Similar to other brittle materials, tensile strength of cemented carbides depends on the size of the major flaw and exhibits wide scatter due to the variability associated with defect distribution.…”

Section: Introductionmentioning

confidence: 99%

Strength and reliability of WC-Co cemented carbides: Understanding microstructural effects on the basis of R-curve behavior and fractography

Tarragó

Coureaux

Torres

et al. 2018

International Journal of Refractory Metals and Hard Materials

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Strength and reliability of WC-Co cemented carbides (hardmetals) are dependent on effective fracture toughness as well as on nature, size and distribution of processing flaws. Regarding toughness, they exhibit a crack growth resistance (R-curve) behavior, derived from the development of a multiligament bridging zone at the crack wake. Accordingly, successful implementation of fracture mechanics requires consideration of tangency criterion, between applied stress intensity factor and R-curve, in addition to fractographic inspection. It is the aim of this study to evaluate the strength behavior of a series of experimental WC-Co grades on the basis of R-curve failure criteria. Results indicate that microstructural effects on the strength of hardmetals may be satisfactorily rationalized following the referred criterion.The analysis includes consideration of nature and distribution of fracture origins, found to be more diverse and wider respectively for the harder fine-grained grades. This experimental evidence, together with the fact that these hardmetals exhibit steeper rising R-curves than tougher coarse-grained ones, leads to lower reliability for the former. This investigation documents and validates the great relevance of R-curve behavior for optimizing the mechanical performance of WC-Co cemented carbides on the basis of microstructural design.

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“…Conventional WC-Co cemented carbides are characterized by poor corrosion resistance in acid or neutral aqueous solutions for pH ≤7 due to the susceptibility of Co to wet corrosion [3]. In neutral and acidic medium, the selective dissolution of the Co matrix occurs while WC particles are not affected by the corrosion attack; while at alkaline pH values, the passivation of the Co matrix occurs and WC is dissolved [3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Corrosion Behavior of Near-Nano and Nanostructured WC-Co Cemented Carbides

Alar

Fabijanić

2017

Metals

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Abstract:In this paper, the electrochemical corrosion resistance of near-nano and nanostructured WC-Co cemented carbides was investigated. WC powders with an average grain size d BET in the range from 95 nm to 150 nm and with an addition of vanadium carbide (VC) and chromium carbide Cr 3 C 2 as grain growth inhibitors were used as starting powders. The mixtures with 6 wt. % and 9 wt. % Co were consolidated by two different processes; sintering in hydrogen atmosphere and the sinter-HIP process. WC-Co samples were researched by direct current and alternating current techniques in the solution of 3.5% NaCl at room temperature. Corrosion parameters such as corrosion potential (E corr ), corrosion current density (j corr ) and polarization resistance (R p ) were determined by electrochemical techniques. From the conducted research, it was found that the consolidation processes and microstructural characteristics-grain growth inhibitors, grain size of the starting WC powders and η-phase-influenced the electrochemical corrosion resistance. η-phase enhanced the formation of a passive layer on the samples' surfaces, thereby reducing the tendency of the sample dissolution and increasing the stability of oxides forming therewith a passive layer on the sample surface.

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Corrosion damage in WC–Co cemented carbides: residual strength assessment and 3D FIB-FESEM tomography characterisation

Cited by 26 publications

References 29 publications

FIB/FESEM experimental and analytical assessment of R-curve behavior of WC–Co cemented carbides

FIB/FESEM experimental and analytical assessment of R-curve behavior of WC–Co cemented carbides

Strength and reliability of WC-Co cemented carbides: Understanding microstructural effects on the basis of R-curve behavior and fractography

Electrochemical Corrosion Behavior of Near-Nano and Nanostructured WC-Co Cemented Carbides

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