Recently, PcBN tooling have been successfully introduced in machining Ni-based superalloys, yet our knowledge of involved wear mechanisms remains limited. In this study, an in-depth investigation of PcBN tool degradation and related wear mechanisms when machining Inconel 718 was performed. Diffusional dissolution of cBN is an active wear mechanism. At high cutting speed oxidation of cBN becomes equally important. Apart from degradation, tool protection phenomena were also discovered. Oxidation of Inconel 718 resulted in formation of γ-Al2O3 and (Al,Cr,Ti)3O4 spinel that were deposited on the tool rake. Also on the rake, formation of (Ti,Nb,Cr)N takes place due to cBN-workpiece interaction. This creates a sandwich tool protection layer forming continuously as tool wear progresses. Such in operando protection enabled counterbalancing tool wear mechanisms and achieved high performance of PcBN in machining.
Bibliographical noteFunding Information:
This research was partly funded by European Union's Horizon 2020 Research and Innovation Programme under Flintstone 2020 project (grant agreement No. 689279 ). It was also co-funded by strategic research programme of Sustainable Production Initiative (SPI), involving cooperation between Lund University and Chalmers University of Technology. The authors also would like to express their gratitude to Dr. Mathias Agmell for the help with FEM simulations. Authors are grateful to E. Brug ( University of Cambridge ) for fruitful and inspiring discussions.
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Subject classification (UKÄ)
- Manufacturing, Surface and Joining Technology