中高的纳米合金的三维原子结构和局部化学顺序
Saman Moniri1, Yao Yang1, Jun Ding2
1Department of Physics and Astronomy and California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, USA.
Nature
|December 20, 2023
概括
研究人员对中高合金中的3D原子结构进行了可视化. 他们发现这些合金中的应变与化学短程顺序 (CSRO) 相对应,揭示了对材料特性的新见解.
科学领域:
- 材料科学
- 金属工程
- 纳米技术
背景情况:
- 中高合金 (M/HEAs) 是具有近等原子组成的新材料,在材料设计中提供了范式转变.
- M/HEAs的一个关键假设是晶格扭曲,但它的3D表征和元素混合程度 (随机与有序) 仍然具有挑战性.
- 之前的研究表明M/HEAs的局部化学秩序,但直接的3D实验观察这种秩序及其与结构缺陷的相关性是难以捉摸的.
研究的目的:
- 确定M/HEA纳米粒子中的3D原子位置和局部格子扭曲,应变和化学短距离顺序 (CSRO).
- 在M/HEAs中调查格子扭曲,应变异质和CSRO之间的关系.
- 通过实验观察和理解CSRO在调解结构缺陷中的作用.
主要方法:
- 使用原子电子断层扫描来重建M/HEA纳米粒子的3D原子位置.
- 量化分析了局部格子扭曲,应变张力,双边界,脱位核心和化学短距离顺序 (CSRO).
- 与当地化学秩序的程度和性质相关的观察到的结构缺陷.
主要成果:
- 与中等度合金相比,高度合金具有更大的局部晶格扭曲和更异质的应变.
- 在M/HEA结构中发现了菌株分布和CSRO之间的直接相关性.
- 在中等度合金中观察到CSRO介导的结合,在能源不利的CSRO区域中进行结合.
结论:
- 这项研究提供了第一个将局部化学秩序与任何材料系统的结构缺陷联系起来的实验证据.
- 通过阐明格子扭曲,应变和CSRO之间的相互作用,这些发现有助于对M/HEAs的基本理解.
- 这些结果为通过针对性地设计格子扭曲和局部化学秩序来定制M/HEA属性提供了基础.
相关概念视频
Metallic Solids
18.4K
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....
18.4K
Ionic Crystal Structures
14.4K
Ionic crystals consist of two or more different kinds of ions that usually have different sizes. The packing of these ions into a crystal structure is more complex than the packing of metal atoms that are the same size.
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
14.4K
Structures of Solids
14.2K
Solids in which the atoms, ions, or molecules are arranged in a definite repeating pattern are known as crystalline solids. Metals and ionic compounds typically form ordered, crystalline solids. A crystalline solid has a precise melting temperature because each atom or molecule of the same type is held in place with the same forces or energy. Amorphous solids or non-crystalline solids (or, sometimes, glasses) which lack an ordered internal structure and are randomly arranged. Substances that...
14.2K
Molecular Orbital Theory II
19.2K
Molecular Orbital Energy Diagrams
19.2K
Lattice Centering and Coordination Number
9.6K
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...
9.6K
Valence Bond Theory
8.6K
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
8.6K


