グループ4の移行金属による超硬質のトングステンテトラボリド合金による外部の硬化
Georgiy Akopov, Michael T Yeung, Christopher L Turner
1Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University , Richmond, Virginia 23284, United States.
Journal of the American Chemical Society
|April 27, 2016
まとめ
タイタン,ジルコニウム,ハフニウムを含む新しいトングステンテトラボリド (WB4) 合金は,超硬質性および強化された酸化耐性を示す. これらの先進的な金属ボリドは,機械性能と熱安定性において顕著な改善を示しています.
科学分野:
- 材料科学
- 固体化学
- 機械工学
背景:
- トングステンテトラボリド (WB4) は,超硬い物質として知られています.
- 移行金属とWB4の合金を探索することで,その性質を高めることができます.
研究 の 目的:
- Ti,Zr,HfによるWB4合金の合成と機械的性質を調査する.
- 硬度,酸化抵抗,インデントサイズ効果に対する合金効果を決定する.
主な方法:
- Ti,Zr,Hfの濃度が異なるWB4合金のアーチ溶融合成
- 粉末X線微分法 (PXRD) とエネルギー分散型X線スペクトル法 (EDS) を用いた相組成分析.
- ビッカースインデントによる機械性能試験
主要な成果:
- 溶解性の限界は,20%Ti,10%Zr,8%Hfが決定された.
- 合成された超硬質合金 (HV>40GPa),硬度が純粋なWB4を超える.
- W0.92Zr0.08B4は,特殊な硬さ (4.9N負荷で34.7GPa) とナノ構造の粒子を示した.
- 酸化抵抗は,純粋なWB4の400°Cと比較して,~460~510°Cに増加した.
結論:
- グループ4の移行金属を持つWB4合金は,優れた機械性能と酸化耐性を有しています.
- 外部硬化とナノ構造は これらの合金の超硬化に寄与する.
- これらの材料は,高硬度と熱安定性を要求するアプリケーションに潜在しています.
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