オーダーされた酸素複合体による高エントロピー合金における強度と柔らかさの強化
Zhifeng Lei1, Xiongjun Liu1, Yuan Wu1
1Beijing Advanced Innovation Center for Materials Genome Engineering, State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing, China.
Nature
|November 16, 2018
まとめ
酸素は,高エントロピー合金 (HEAs) の金属の強さと柔らかさを同時に高めることができます. この研究は オーダーされた酸素複合体という 新しい状態を明らかにし 金属材料における 伝統的な強度-柔らかさのトレードオフを 破ったのです
科学分野:
- 材料科学
- 金属工学
- 固体化学
背景:
- 酸素は通常金属の中間不純物であり,脆性を引き起こします.
- 金属を酸素で強化する伝統的な方法は,柔らかさの喪失につながります.
- 高エントロピー合金 (HEA) は,新しい強化メカニズムを探求するためのユニークなプラットフォームを提供します.
研究 の 目的:
- 高エントロピー合金における秩序ある酸素複合体の形成と効果を調査する.
- これらの複合体が同時に強度と柔らかさの両方を高めることができるかどうかを判断する.
- オーダーされた酸素複合体による強化メカニズムを解明する.
主な方法:
- モデルTiZrHfNb HEAのドーピングで 酸素の原子比率は2.
- ナノスケール画像と分析を用いた酸素複合体の特徴化.
- 機械的特性 (強度,柔らかさ) を評価するための牽引試験.
- 脱位行動と変形メカニズムの分析
主要な成果:
- HEAマトリックス内のナノスケール酸素複合体の形成.
- 牽引強度 (48.5%) と柔らかさ (95.2%) の有意な強化が酸素ドーピングされたHEAで示された.
- 長年にわたる強度-柔らかさのトレードオフの破損が観察されました.
- 変位切断モードと増殖を含む新しいストレスの硬化メカニズムを特定する.
結論:
- オーダーされた酸素複合体は,HEAにおけるインタースティシャル酸素の新しい状態を表します.
- この新しい複合構造は 同時に強さと柔らかさを高め 前の限界を克服します
- この発見は,先進的な金属材料,特にTi,Zr,Hfを含むものを設計するための新しい戦略を提供します.
関連する概念動画
02:39Entropy
36.1K
Salt particles that have dissolved in water never spontaneously come back together in solution to reform solid particles. Moreover, a gas that has expanded in a vacuum remains dispersed and never spontaneously reassembles. The unidirectional nature of these phenomena is the result of a thermodynamic state function called entropy (S). Entropy is the measure of the extent to which the energy is dispersed throughout a system, or in other words, it is proportional to the degree of disorder of a...
36.1K
01:18Entropy
3.6K
The first law of thermodynamics is quantitatively formulated via an equation relating the internal energy of a system, the heat exchanged by it, and the work done on it. A quantitative formulation of the second law of thermodynamics leads to defining a state function, the entropy.
When an ideal gas expands isothermally, the disorder in the gas increases. From the molecular perspective, the gas molecules have more volume to move around in.
Consider an infinitesimal step in the expansion, which...
When an ideal gas expands isothermally, the disorder in the gas increases. From the molecular perspective, the gas molecules have more volume to move around in.
Consider an infinitesimal step in the expansion, which...
3.6K
03:00Standard Entropy Change for a Reaction
24.6K
Entropy is a state function, so the standard entropy change for a chemical reaction (ΔS°rxn) can be calculated from the difference in standard entropy between the products and the reactants.
24.6K
03:05Acid Strength and Molecular Structure
33.1K
Binary Acids and Bases
In the absence of any leveling effect, the acid strength of binary compounds of hydrogen with nonmetals (A) increases as the H-A bond strength decreases down a group in the periodic table. For group 17, the order of increasing acidity is HF < HCl < HBr < HI. Likewise, for group 16, the order of increasing acid strength is H2O < H2S < H2Se < H2Te. Across a row in the periodic table, the acid strength of binary hydrogen compounds increases with increasing...
In the absence of any leveling effect, the acid strength of binary compounds of hydrogen with nonmetals (A) increases as the H-A bond strength decreases down a group in the periodic table. For group 17, the order of increasing acidity is HF < HCl < HBr < HI. Likewise, for group 16, the order of increasing acid strength is H2O < H2S < H2Se < H2Te. Across a row in the periodic table, the acid strength of binary hydrogen compounds increases with increasing...
33.1K
02:05Entropy and Solvation
8.4K
The process of surrounding a solute with solvent is called solvation. It involves evenly distributing the solute within the solvent. The rule of thumb for determining a solvent for a given compound is that like dissolves like. A good solvent has molecular characteristics similar to those of the compound to be dissolved. For example, polar solutions dissolve polar solutes, and apolar solvents dissolve apolar solutes. A polar solvent is a solvent that has a high dielectric constant (ϵ...
8.4K
01:22Entropy within the Cell
12.9K
A living cell's primary tasks of obtaining, transforming, and using energy to do work may seem simple. However, the second law of thermodynamics explains why these tasks are harder than they appear. None of the energy transfers in the universe are completely efficient. In every energy transfer, some amount of energy is lost in a form that is unusable. In most cases, this form is heat energy. Thermodynamically, heat energy is defined as the energy transferred from one system to another that...
12.9K