Wear, Plasticity, and Rehybridization in Tetrahedral Amorphous Carbon
Wear, Plasticity, and Rehybridization in Tetrahedral Amorphous Carbon
Kunze, T.; Posselt, M.; Gemming, S.; Konicek, A. R.; Carpick, R. W.; Pastewka, L.; Moseler, M.
Abstract Wear in self-mated tetrahedral amorphous carbon (ta-C) films is studied by molecular dynamics and nearedge X-ray absorption fine structure spectroscopy. Both theory and experiment demonstrate the formation of a soft amorphous carbon (a-C) layer with increased sp2 content, which grows faster than an a-C tribolayer found on selfmated diamond sliding under similar conditions. The faster sp3 --> sp2 transition in ta-C is explained by easy breaking of prestressed bonds in a finite, nanoscale ta-C region, whereas diamond amorphization occurs at an atomically sharp interface. A detailed analysis of the underlying rehybridization mechanism reveals that the sp3 --> sp2 transition is triggered by plasticity in the adjacent a-C. Rehybridization therefore occurs in a region that has not yet experienced plastic yield. The resulting soft a-C tribolayer is interpreted as a precursor to the experimentally observed wear.
Keywords: wear; tribology; amorphous carbon; computer simulations; X-ray absorption fine structure sprectroscopy
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Tribology Letters 53(2014), 119-126
Online First (2013) DOI: 10.1007/s11249-013-0250-7
Cited 88 times in Scopus -
Poster
7th International Conference on Multiscale Materials Modeling (MMM 2014), 06.-10.10.2014, Berkeley, USA
Permalink: https://www.hzdr.de/publications/Publ-19514