纳米晶体金属的颗粒大小依赖的热膨胀
Pär A T Olsson1,2, Ibrahim Awala1, Jacob Holmberg-Kasa1,3
1Materials Science and Applied Mathematics, Malmö University, SE-205 06 Malmö, Sweden.
Materials (Basel, Switzerland)
|July 29, 2023
概括
纳米晶体铜的热膨胀系数 (CTE) 随着颗粒大小的减少而增加,这是由于颗粒边界的变化造成的. 这项研究为CTE行为提供了一个预测建模工具.
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
- 计算材料科学科学 计算材料科学
背景情况:
- 纳米晶体材料表现出独特的属性,受颗粒大小的影响.
- 热膨胀系数 (CTE) 是一种关键的材料属性,影响各种应用中的性能.
- 了解颗粒大小对CTE的影响对于设计先进材料至关重要.
研究的目的:
- 为了研究颗粒大小和纳米晶体铜的CTE之间的关系.
- 阐明控制粒度大小依赖热膨胀的原子化机制.
- 在纳米晶体材料中开发CTE的预测建模框架.
主要方法:
- 经典的分子动力学模拟.
- 量子力学密度函数理论 (DFT) 的计算.
- 开发初始热膨胀图的开发.
主要成果:
- 随着谷粒大小的减少,CTE增加了高达20%.
- 观察到的行为归因于增加的抗结合状态和在谷物边界的结合顺序变化.
- 建立了一个生成初始热膨胀图的程序.
结论:
- 颗粒边界特征显著影响纳米晶体铜的热膨胀.
- 开发的建模工具可以预测谷粒大小依赖的CTE.
- 这种方法可以扩展到研究杂质对CTE的影响.
相关概念视频
Thermal Strain
1.7K
Thermal strain is a concept that arises when we consider how temperature changes affect structures. Unlike the conventional assumption that structures remain constant under load, real-world scenarios often involve temperature fluctuations that can significantly impact these structures. Consider a homogeneous rod with a uniform cross-section resting freely on a flat horizontal surface. If the rod's temperature increases, the rod elongates. This elongation is proportional to the temperature...
1.7K
Thermal expansion and Thermal stress: Problem Solving
1.2K
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...
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...
1.2K
Thermal Expansion
4.4K
The expansion of alcohol in a thermometer is one of many commonly encountered examples of thermal expansion, which is the change in size or volume of a given system as its temperature changes. The most visible example is the expansion of hot air. When air is heated, it expands and becomes less dense than the surrounding air, which then exerts an upward force on the hot air to, for example, make steam and smoke rise, and hot air balloons float. The same behavior happens in all liquids and gases,...
4.4K
Thermal Stress
2.5K
If the temperature of an object is changed while it is prevented from expanding or contracting, the object is subjected to stress. The stress is compressive if the object expands in the absence of constraint and tensile if it contracts. This stress resulting from temperature change is known as thermal stress. It can be quite large and can cause damage. To avoid this stress, engineers may design components so they can expand and contract freely. For instance, on highways, gaps are deliberately...
2.5K


