体中心の立方金属の異常な滑り
Daniel Caillard1, Baptiste Bienvenu2, Emmanuel Clouet3
1CEMES-CNRS, Toulouse, France. daniel.caillard@cemes.fr.
Nature
|September 28, 2022
まとめ
体中心の立方金属の異常な滑り方は,高度に移動可能な多重結合の変位によって引き起こされます. ダイナミックに形成されたこれらの交差点は 単一の変位よりもはるかに速く滑り込み 複雑なプラスチック流動の振る舞いを説明します
科学分野:
- 材料科学
- 固体力学
- クリスタルグラフィー
背景:
- 結晶の可塑性と強さは 変位運動と相互作用に依存する.
- ボディセンター立方体 (BCC) の金属は複雑な可塑性を持ち,特に低温では,最大限の切断ストレスを持たないシステムで滑り出します.
- この現象は異常滑りとして知られており,典型的な結晶学的変形パターンから逸脱する.
研究 の 目的:
- BCC金属の異常な滑り方に 原因となるメカニズムを調査する
- プラスチックの変形を制御する際の変位相互作用と交差点形成の役割を明らかにする.
- 脱位行動に関する理論的予測と実験的観測を調和させる.
主な方法:
- トランスミッション電子顕微鏡 (TEM) の内部での引力試験で,変位の動態を観察する.
- 変位相互作用と交差点の安定性をモデル化するための原子模擬.
- 変位滑行速度と圧迫下での交差点形成の分析
主要な成果:
- BCCの金属の異常な滑り方は,複数の接点の高度な移動性 (>2の変位の接点) に起因する.
- 単発の変位を大幅に上回る速度で滑ります.
- ダイナミックな条件により,トングステンのような弾性アニゾトロプ的BCC金属では不安定であると予測されるバイナリ結合の形成が可能です.
結論:
- 動的に形成された多重結合の高度な移動性は,BCC金属における異常な滑り方の主要な原因である.
- 実験とシミュレーションの結果は,これらの移動交差点の存在と重要性を確認しています.
- この発見は,トラングステンを含む様々なBCC金属に異常な滑り込みが広範囲に広がっていることを説明します.
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