Ab initio study of boron-rich amorphous boron carbides |
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Authors: | Tevhide Ayça Yıldız Murat Durandurdu |
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Affiliation: | Materials Science and Mechanical Engineering Program and Department of Nanotechnology Engineering, Abdullah Gül University, Kayseri, Turkey |
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Abstract: | Amorphous boron carbide compositions having high B contents (BxC1−x, 0.50 ≤ x ≤ 0.95) are systematically created by way of ab initio molecular dynamics calculations, and their structural, electrical, and mechanical characteristics are inclusively investigated. The coordination number of both B and C atoms increases progressively with increasing B/C ratio and more close-packed materials having pentagonal pyramid motifs form. An amorphous diamond-like local arrangement is found to be dominant up to 65% B content, and beyond this content, a mixed state of amorphous diamond– and B-like structures is perceived in the models because sp3 hybridization around C atoms is still leading one for all compositions. The pentagonal pyramid motifs around C atoms are anticipated to appear beyond 65% content. The intericosahedral linear C–B–C chains do not form in any model. All amorphous boron carbides are semiconducting materials. The mechanical properties gradually increase with increasing B concentration, and some amorphous compositions are proposed to be hard materials on the basis of their Vickers hardness estimation. |
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Keywords: | amorphous boron carbide boron-rich first-principles calculations mechanical properties |
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