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arXiv · 1203.1748

Polycrystalline γ-boron: As hard as polycrystalline cubic boron nitride

Jiaqian Qin·Norimasa Nishiyama·Hiroaki Ohfuji·Toru Shinmei·Li Lei·Duanwei He·Tetsuo Irifune
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Abstract

The Vickers hardness of polycrystalline γ-B was measured using a diamond indentation method. The elastic properties of polycrystalline γ-B (B=213.9 GPa, G=227.2 GPa, and E=503.3 GPa) were determined using ultrasonic measurement at ambient condition. Under the loading force up to 20 N, our test gave an average Vickers hardness in the asymptotic-hardness region of 30.3 GPa. The average fracture toughness was measured as 4.1MPa m1/2. Additionally, We also measured the hardness and elastic properties of polycrystalline β-B and PcBN for comparison. The hardness and elastic properties for polycrystalline γ-B was found to be very close to that of PcBN. Our results suggest that the polycrystalline γ-B could be a superhard polycrystalline material for industrial applications.

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Jiaqian Qin, Norimasa Nishiyama, Hiroaki Ohfuji, Toru Shinmei, Li Lei, Duanwei He, Tetsuo Irifune. 2012-05-16. Polycrystalline γ-boron: As hard as polycrystalline cubic boron nitride. https://doi.org/10.1016/j.scriptamat.2012.04.032

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