関連する実験動画
Updated: Nov 3, 2025
06:45
Negative Additive Manufacturing of Complex Shaped Boron Carbides
Published on: September 18, 2018
8.8K
本質的な硬化と安定したクラック伝播を六角性酸塩で
Yingchao Yang1,2, Zhigong Song3,4,5, Guangyuan Lu6
1Department of Materials Science and NanoEngineering, Rice University, Houston, TX, USA.
Nature
|June 3, 2021
まとめ
六角性酸塩 (h-BN) は驚くほど高い断裂強度を示し,以前からの脆性仮定に異議を唱える. この発見は,高度な材料の応用のための新しい道を開きます.
科学分野:
- 材料科学
- ナノテクノロジー
- 固体力学
背景:
- 散発材料はしばしば強度と断裂強度とのトレードオフを示し,壊れやすい失敗につながります.
- グラフェンのような二次元材料は 高い強度にもかかわらず 通常は脆いものです
- 六角性ボルニトリド (h-BN) は,グラフェンの脆い骨折行動を共有すると推定された.
研究 の 目的:
- 単一結晶の六角性ボロンニトリド (h-BN) の断裂強さを調査する.
- H-BNの脆弱性に関する 普遍的な仮定に異議を唱えるため
- H-BNの骨折の背後にあるメカニズムを探るためだ
主な方法:
- 単層のh-BNにおける亀裂伝播の現地実験観測
- 実験結果を裏付ける理論的分析
- 効率的なエネルギー放出率とクラック抵抗の曲線の測定
主要な成果:
- モノレイヤのh-BNは,グリフィスの法則によって予測され,グラフェンについて報告されたよりも著しく高い断裂強度を示しています.
- 単層のh-BNで安定したクラック伝播が観察された.
- アシンメトリックな縁の性質と縁の交換によって引き起こされる裂け目や分岐は,固有の硬化に寄与する.
結論:
- シングル・クリスタル・モノレイヤ h-BNは 驚くほど堅固で 期待を裏切ります
- 観察された硬化メカニズムは,安定した亀裂の拡散を可能にします.
- これらの発見は,二次元デバイスの保護におけるh-BNの実用的な利点を示唆し,新しい技術的機会を提供します.
関連する概念動画
01:24Stress-Strain Diagram - Brittle Materials
3.1K
Brittle materials, including glass, cast iron, and stone, exhibit unique characteristics. They fracture without considerable change in their elongation rate, indicating that their breaking and ultimate strength are equivalent. Such materials also show lower strain levels at the point of rupture. The failure in brittle materials predominantly results from normal stresses, as evidenced by the rupture created along a surface perpendicular to the applied load. These materials do not display...
3.1K
02:33Lattice Centering and Coordination Number
10.5K
The structure of a crystalline solid, whether a metal or not, is best described by considering its simplest repeating unit, which is referred to as its unit cell. The unit cell consists of lattice points that represent the locations of atoms or ions. The entire structure then consists of this unit cell repeating in three dimensions. The three different types of unit cells present in the cubic lattice are illustrated in Figure 1.
Types of Unit Cells
Imagine taking a large number of identical...
Types of Unit Cells
Imagine taking a large number of identical...
10.5K
02:18Network Covalent Solids
15.3K
Network covalent solids contain a three-dimensional network of covalently bonded atoms as found in the crystal structures of nonmetals like diamond, graphite, silicon, and some covalent compounds, such as silicon dioxide (sand) and silicon carbide (carborundum, the abrasive on sandpaper). Many minerals have networks of covalent bonds.
To break or to melt a covalent network solid, covalent bonds must be broken. Because covalent bonds are relatively strong, covalent network solids are typically...
To break or to melt a covalent network solid, covalent bonds must be broken. Because covalent bonds are relatively strong, covalent network solids are typically...
15.3K
02:37Metallic Solids
19.8K
Metallic solids such as crystals of copper, aluminum, and iron are formed by metal atoms. The structure of metallic crystals is often described as a uniform distribution of atomic nuclei within a “sea” of delocalized electrons. The atoms within such a metallic solid are held together by a unique force known as metallic bonding that gives rise to many useful and varied bulk properties.
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability....
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability....
19.8K
02:30Stability of Substituted Cyclohexanes
13.9K
This lesson discusses the stability of substituted cyclohexanes with a focus on energies of various conformers and the effect of 1,3-diaxial interactions.
The two chair conformations of cyclohexanes undergo rapid interconversion at room temperature. Both forms have identical energies and stabilities, each comprising equal amounts of the equilibrium mixture. Replacing a hydrogen atom with a functional group makes the two conformations energetically non-equivalent.
For example, in...
The two chair conformations of cyclohexanes undergo rapid interconversion at room temperature. Both forms have identical energies and stabilities, each comprising equal amounts of the equilibrium mixture. Replacing a hydrogen atom with a functional group makes the two conformations energetically non-equivalent.
For example, in...
13.9K
01:20Normal Strain under Axial Loading
826
Normal strain under axial loading is an important concept in the field of mechanics of materials. Axial loading implies the application of a force along the axis of a material, like a column or bar. This force can either compress or stretch the material. In the context of axial loading, normal strain is the deformation experienced by the material in the direction of the loading force. It's calculated as the change in length divided by the original length of the material. This unitless ratio...
826