Assessment of wear micromechanisms on a laser textured cemented carbide tool during abrasive-like machining by FIB/FESEM
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ISSN 2223-7690 CN 10-1237/TH
SHORT COMMUNICATION
Assessment of wear micromechanisms on a laser textured cemented carbide tool during abrasive-like machining by FIB/FESEM Shiqi FANG1,2,*, Dirk BÄHRE1, Luis LLANES2 1
Institute of Production Engineering, Saarland University, Saarbrücken 66123, Germany
2
CIEFMA–Department of Materials Science and Engineering, EEBE–Campus Diagonal Besòs, Universitat Politècnica de
Catalunya, Barcelona 08019, Spain Received: 29 November 2019 / Revised: 20 March 2020 / Accepted: 07 May 2020
© The author(s) 2020. Abstract: The combined use of focused ion beam (FIB) milling and field-emission scanning electron microscopy inspection (FESEM) is a unique and successful approach for assessment of near-surface phenomena at specific and selected locations. In this study, a FIB/FESEM dual-beam platform was implemented to docment and analyze the wear micromechanisms on a laser-surface textured (LST) hardmetal (HM) tool. In particular, changes in surface and microstructural integrity of the laser-sculptured pyramids (effective cutting microfeatures) were characterized after testing the LST-HM tool against a steel workpiece in a workbench designed to simulate an external honing process. It was demonstrated that: (1) laser-surface texturing does not degrade the intrinsic surface integrity and tool effectiveness of HM pyramids; and (2) there exists a correlation between the wear and loading of shaped pyramids at the local level. Hence, the enhanced performance of the laser-textured tool should consider the pyramid geometry aspects rather than the microstructure assemblage of the HM grade used, at least for attempted abrasive applications. Keywords: focused ion beam (FIB); field-emission scanning electron microscopy inspection (FESEM); cemented carbides; laser surface texturing; abrasive machining processes; wear
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Introduction
Continuous or interrupted sliding contact between hard tools and counterparts is intrinsic to all machining operations of metallic alloys. As a result, the piece gets shaped, but also the cutting tool gets worn. The amount and extensiveness of wear is the synergic result of many different factors in the tribological system, including contact and lubrication conditions as well as material properties. Reliable assessment of degradation phenomena associated with the wear of cutting tools requires both two-dimensional and three-dimensional characterization, directly
linked to surface and subsurface scenarios, respectively. Cross-sectional analysis is a practical and efficient approach to revealing wear information related to subsurface integrity and microstructural changes [1–3]. Metallographic sample preparation on crosssections combined with optical and scanning electron microscopy is an inspection protocol often used for acquiring data at the subsurface level. However, the unintended (but possible) introduction of artifacts (e.g., mechanical-induced changes) during the metallographic preparation may be an important drawback. Hence, sample preparation may either affect (
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