温度升高时的液体金属动态:实验的观点
1ISIS Facility, Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom.
概括
液体金属表现出一个动态交叉约1.4倍他们的点. 这种转变将它们的行为从粘性转变为自由流体,这可能是液体金属中的普遍现象.
科学领域:
- 材料科学 材料科学 材料科学
- 凝聚物质物理学 凝聚物质物理学
背景情况:
- 由于其广泛的温度范围,液体金属在技术上很重要.
- 之前的研究集中在接近点的液体金属动力学上,忽视了更高的温度.
研究的目的:
- 在高温下研究液体金属的微观动力学.
- 为了识别液体金属中的温度依赖的动态转变.
主要方法:
- 在液体,,和上进行了散射实验.
- 分子动力学模拟支持了实验结果.
主要成果:
- 观察到一个动态交叉在化温度 (Tm) 的1.4倍左右.
- 集体和单粒子动态表现出明显的变化,表明从粘性向自由流体行为的过渡.
- 固有结构能量计算支持液体的这种转变.
结论:
- 液体金属在高温下经历普遍动态交叉.
- 这种过渡重新定义了它们的流体行为,从粘性转向自由流体状态.
更多相关视频
11:11Experimental Methods for Investigation of Shape Memory Based Elastocaloric Cooling Processes and Model Validation
Published on: May 2, 2016
11.5K
08:55Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
8.9K
相关概念视频
Theory of Metallic Conduction
1.7K
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,...
1.7K
Bonding in Metals
51.6K
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”.
51.6K
Heating and Cooling Curves
26.4K
When a substance—isolated from its environment—is subjected to heat changes, corresponding changes in temperature and phase of the substance is observed; this is graphically represented by heating and cooling curves.
For instance, the addition of heat raises the temperature of a solid; the amount of heat absorbed depends on the heat capacity of the solid (q = mcsolidΔT). According to thermochemistry, the relation between the amount of heat absorbed or released by a substance, q, and its...
For instance, the addition of heat raises the temperature of a solid; the amount of heat absorbed depends on the heat capacity of the solid (q = mcsolidΔT). According to thermochemistry, the relation between the amount of heat absorbed or released by a substance, q, and its...
26.4K
Effect of Temperature Change on Reaction Rate
4.9K
The Arrhenius equation,
4.9K
Phase Transitions: Melting and Freezing
14.5K
Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy becomes large enough to partially overcome the forces holding the molecules or ions of the solid in their fixed positions, and the solid begins the process of transitioning to the liquid state or melting. At this point, the temperature of the solid stops rising, despite the continual input of heat, and it remains constant until all of the solid is...
14.5K
Thermal expansion and Thermal stress: Problem Solving
2.0K
San Francisco's Golden Gate Bridge is exposed to temperatures ranging from -15 °C to 40 °C. At its coldest, the main span of the bridge is 1275 m long. Assuming that the bridge is made entirely of steel, what is the change in its length between these temperatures?
To solve the problem, first, identify the known and unknown quantities. The initial length (L) of the bridge is 1275 m, the coefficient of linear expansion (α) for steel is 12 x 10-6/°C, and the change in temperature (ΔT) is 55...
To solve the problem, first, identify the known and unknown quantities. The initial length (L) of the bridge is 1275 m, the coefficient of linear expansion (α) for steel is 12 x 10-6/°C, and the change in temperature (ΔT) is 55...
2.0K
