オスミウムジボリドは超硬質な材料ですか?
Jun Yang1, Hong Sun, Changfeng Chen
1Department of Physics, Shanghai Jiao Tong University, Shanghai 200240, China.
Journal of the American Chemical Society
|May 16, 2008
まとめ
第一原理による計算により,OsB2はアニゾトロピックな切断強度を示していることが明らかになった. (001) [100]シアに対する高い耐性は,超硬い性質に貢献しますが,弱い (001) [010]シアはいくつかのアプリケーションを制限します.
科学分野:
- マテリアルサイエンス 材料科学
- コンピューティング・マテリアル・サイエンス・サイエンス
- 固体物理 固体物理学
背景:
- オスミウムジボリド (OsB2) は,超硬質材料の新種である.
- これらの材料は,軽量で共性元素と重過渡金属を組み合わせている.
- 変形メカニズムを理解することは,新しい硬質材料の設計に不可欠です.
研究 の 目的:
- オーソロンビックOsB2.2の理想的な張力および切断強さを調査するために.
- その機械的性質を支配する原子的変形モードを解明する.
- 計算された強度と実験的な硬さ観測を相関させるため.
主な方法:
- 機械的振る舞いをシミュレートするために,第一原理の計算が採用されました.
- 張力および切断強度の計算は,オーソロンビック OsB2 構造で実行されました.
- 切断強度のアニゾトロピーは,異なる結晶学的な方向で分析されました.
主要な成果:
- オーソロンビックOsB2は, (001) 平面で高度にアニソトロピックな切断力を示す.
- ピーク・シーア・ストレスは, (001) [100]方向 (26.9 GPa) と (001) [010]方向 (9.1 GPa) に比べて, (001) [100]方向 (26.9 GPa) で大幅に高かった.
- 計算した強度は, (001) 平面における実験的なビッカース硬度30 GPaと一致する.
結論:
- (001) [100] 切断変形に対する強い抵抗が,OsB2の高いビッカース硬さの原因である.
- 弱い (001) [010] 切断強度は,磨き物および切断アプリケーションでの使用を制限します.
- アニゾトロプ的変形モードを理解することは,高度な超硬質材料の合理的な設計に不可欠です.
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