[en] Composed of hard tungsten carbide (WC) particles and a soft cobalt (Co) matrix, WC–Co cemented carbides exhibit significant differences in the material removal rates of these phases during metallographic preparation. This disparity, combined with the susceptibility of the soft Co phase to deformation-induced martensitic phase transformation from its face-centered cubic (CoFCC) to hexagonal close-packed (CoHCP) structure, poses substantial challenges for microstructural characterisation. The resulting ambiguity complicates the identification of the pristine Co phase and raises concerns about the presence of preparation-induced artefacts. In this study, we present a detailed comparative analysis aimed at minimizing ambiguities in the characterisation of the pristine Co phases in a series of WC–Co cemented carbides. We quantitatively report on the controllability of various preparation parameters under multiple conditions, for plane-polished cross-sections used in (e.g.) EBSD analysis and for thin-sections such as used in (e.g.) TEM analysis. We report on the interplay between material removal and the deformation-induced martensitic CoFCC–CoHCP phase transformation during metallographic preparation, identifying “GO” and “NO GO” regimes for the unequivocal identification of the pristine Co phase in WC–Co cemented carbides. The optimal metallographic preparation method for the “GO” regime involves an Ar+ ion polishing energy density of ∼10 MJ/m2 and a duration of ∼80 min. This work establishes a robust workflow for accurately determining the pristine Co phase, providing a pivotal aspect for the characterisation of microstructure–property relationships in WC–Co cemented carbides.
Disciplines :
Materials science & engineering
Author, co-author :
Zhou, Haoruo; School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, Australia ; Australian Centre for Microscopy and Microanalysis, The University of Sydney, Sydney, Australia
Chen, Hansheng; School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, Australia ; Australian Centre for Microscopy and Microanalysis, The University of Sydney, Sydney, Australia
Czettl, Christoph; R&D Carbide and Coating, CERATIZIT Austria GmbH, Reutte, Austria
Weirather, Thomas; R&D Carbide and Coating, CERATIZIT Austria GmbH, Reutte, Austria
Pachlhofer, Julia; R&D Carbide and Coating, CERATIZIT Austria GmbH, Reutte, Austria
Mueller, Pauline; R&D Carbide and Coating, CERATIZIT Austria GmbH, Reutte, Austria
Teppernegg, Tamara; R&D Carbide and Coating, CERATIZIT Austria GmbH, Reutte, Austria
USELDINGER, Ralph ; University of Luxembourg > Faculty of Science, Technology and Medicine (FSTM) > Department of Engineering (DoE) ; CERATIZIT Luxembourg S. à r.l., Mamer, Luxembourg
Primig, Sophie; School of Materials Science & Engineering, UNSW, Sydney, Australia
Ringer, Simon P.; School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, Australia ; Australian Centre for Microscopy and Microanalysis, The University of Sydney, Sydney, Australia
External co-authors :
no
Language :
English
Title :
Identification and accurate characterisation of the metastable CoFCC phase in WC–Co cemented carbides
Original title :
[en] Identification and accurate characterisation of the metastable CoFCC phase in WC–Co cemented carbides
The authors acknowledge the facilities, the scientific, and technical assistance of the teams at Sydney Microscopy & Microanalysis (SMM) and Sydney Analytical (SA), which are Core Research Facilities at the University of Sydney. SMM is the University of Sydney\u201Ds (USYD) node of Microscopy Australia. This work was supported by the Australian Research Council (LP190100850). The authors also acknowledge the contributions of Dr. Xiangyuan Cui, Dr. Hongwei Liu and Dr. Ehsan Farabi for their insightful discussions related to this work, and Dr. Kay Song for assistance with preparation of the manuscript.
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