The Molecular Simulation Study on the Thermal Properties of Nanomaterials

• Main Authors: Fu-rong Chang, 張富榮
• Other Authors: I-ling Chang
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/42221719191299790917

碩士 === 國立中正大學 === 機械工程所 === 98 === Due to the improved manufacturing techniques, the applications of nano-materials in various electronic devices have become more and more popular. Since the temperature cycles are usually involved in the production process, it is important to understand the thermal properties of nano-materials so that the designers could have appropriate guideline for device design. Hence, this research is aim to explore the size and crystal orientation effects on the thermal properties, i.e., thermal expansion coefficient (TEC) and melting temperature, of nano-materials using molecular dynamics methods. It is verified in the simulation that the linear TECs of bulk single-crystalline copper are the same along all the crystal orientation. From the simulation results, it is observed that the linear TECs of nanowires are temperature dependent, and the dependence would be affected by the width, axial and surface crystal orientations of the nanowires. If the nanowire is too thin (less than 5nm), it is found that the axial length would decrease as the temperature arises, which is contracted to the normal phenomena. Besides, the melting behavior of copper nanofilm is studed. It is noted that the melting temperature is a certain value, instead of a temperature range as reported in the literature, even for nanofilm. It is learned that the melting temperature of the nanofilm would be influenced by the film thickness and out-of-plane crystal orientation.