纳米结合金属的历史独立循环反应
Qingsong Pan1, Haofei Zhou2, Qiuhong Lu1
1Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China.
Nature
|November 2, 2017
概括
由于疲劳,金属组件经常发生故障. 这项研究揭示了纳米结合铜的新型稳定循环变形机制,
科学领域:
- 材料科学
- 机械工程
- 固体机械学
背景情况:
- 疲劳故障占金属部件服务故障的近90%.
- 由于不可逆转的微观结构损伤,传统金属表现出不稳定的,历史依赖的循环反应.
- 在复杂的负载光谱下预测疲劳寿命仍然是一个重要的工程挑战.
研究的目的:
- 在现实的负载条件下研究纳米双联铜的循环变形行为.
- 确定负责疲劳抵抗的基础微观结构机制.
- 探索新的方法来提高金属材料的疲劳寿命预测.
主要方法:
- 原子模拟被用来在原子水平上建模材料的行为.
- 在散装铜样本上进行了可变应变幅度循环加载实验.
- 微结构分析侧重于高度定向的纳米双胞胎和脱位行为.
主要成果:
- 在纳米双胞胎铜中观察到独立于病史和稳定的循环反应.
- 发现了一种新的"项链"脱机制,涉及相邻双胞胎的相关脱.
- 这种机制稳定双边界,并允许可逆损害积累.
结论:
- 高度定向的纳米双胞胎结构可以表现出独特,稳定的循环变形行为.
- "项链"脱位机制为提高金属疲劳阻力提供了新的途径.
- 这一发现挑战了对金属材料疲劳和损伤积累的传统理解.
相关概念视频
Bonding in Metals
45.6K
Metallic bonds are formed between two metal atoms. A simplified model to describe metallic bonding has been developed by Paul Drüde called the “Electron Sea Model”.
45.6K
Metallic Solids
16.5K
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...
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and...
16.5K
Metal-Ligand Bonds
19.3K
The hemoglobin in the blood, the chlorophyll in green plants, vitamin B-12, and the catalyst used in the manufacture of polyethylene all contain coordination compounds. Ions of the metals, especially the transition metals, are likely to form complexes.
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
19.3K
Ferromagnetism
2.8K
Materials like iron, nickel, and cobalt consist of magnetic domains, within which the magnetic dipoles are arranged parallel to each other. The magnetic dipoles are rigidly aligned in the same direction within a domain by quantum mechanical coupling among the atoms. This coupling is so strong that even thermal agitation at room temperature cannot break it. The result is that each domain has a net dipole moment. However, some materials have weaker coupling, and are ferromagnetic at lower...
2.8K
Theory of Metallic Conduction
2.0K
The conduction of free electrons inside a conductor is best described by quantum mechanics. However, a classical model makes predictions close to the results of quantum mechanics. It is called the theory of metallic conduction.
In this theory, Newton's second law of motion is used to determine the acceleration of an electron in the presence of an applied electric field. Then, its velocity is expressed via this acceleration.
An electron moves through the crystal, containing positive ions,...
In this theory, Newton's second law of motion is used to determine the acceleration of an electron in the presence of an applied electric field. Then, its velocity is expressed via this acceleration.
An electron moves through the crystal, containing positive ions,...
2.0K
Biasing of Metal-Semiconductor Junctions
921
Biasing metal-semiconductor junctions involves applying a voltage across the junction. Specifically, the metal is connected to a voltage source, while the semiconductor is grounded. This technique is essential for controlling the direction and magnitude of current flow in electronic devices, including diodes, transistors, and photovoltaic cells.
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
921


