Thermal expansion/contraction of boron nitride nanotubes in axial, radial and circumferential directions
Thermal expansion/contraction of boron nitride nanotubes in axial, radial and circumferential directions
复制标题
DOI：
10.1016/j.commatsci.2012.08.007
复制
发表时间：
2012-12-01
影响因子：
3.3
通讯作者：
Mashreghi, A.
中科院分区：
文献类型：
--
作者：
Mashreghi, A.
在当前的研究中，对不同直径的扶手椅型氮化硼纳米管（BNNTs）的热膨胀/收缩进行了研究。利用分子动力学模拟，在100 K到700 K的温度范围内确定了BNNTs在轴向、周向和径向的热膨胀系数（CTE）。定义了轴向的两种热膨胀系数：实际轴向热膨胀系数和表观轴向热膨胀系数。所有的BNNTs都表现出实际轴向热膨胀，这是由于B - N键长的热膨胀所致。然而，大直径的BNNTs在低温下表现出表观轴向热收缩。尽管在小直径的BNNTs中未观察到表观轴向热收缩，但其表观轴向热膨胀系数小于实际轴向热膨胀系数。在周向，所有的BNNTs都发生热膨胀。尽管在周向发生热膨胀，但大直径的BNNTs在径向表现出热收缩。通过考虑BNNTs的动态热振动效应以及B - N键长的热膨胀效应，对上述观察结果进行了解释。（C）2012爱思唯尔公司。保留所有权利。
In the present work, thermal expansion/contraction of armchair boron nitride nanotubes (BNNTs) with various diameters was investigated. The coefficient of thermal expansion (CTE) of BNNTs in axial, circumferential and radial directions were determined at temperatures from 100 K to 700 K, using molecular dynamics simulation. Two CTE in axial direction were defined; real axial CTE and apparent axial CTE. All BNNTs showed real axial thermal expansion, which was due to the thermal expansion of B-N bond length. However, large diameter BNNTs exhibited apparent axial thermal contraction at low temperatures. Although the apparent axial thermal contraction was not observed in small diameter BNNTs, their apparent axial CTE was smaller than their real axial CTE. In circumferential direction, all BNNTs were thermally expanded. In spite of thermal expansion in circumferential direction, BNNTs with large diameters exhibited thermal contraction in radial direction. The above observations were explained by considering both the effect of dynamic thermal vibration of BNNTs and the effect of thermal expansion of B-N bond length. (C) 2012 Elsevier B.V. All rights reserved.