Effect of Temperature on Young's Modulus of Graphene
Effect of Temperature on Young's Modulus of Graphene
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DOI：
10.1080/01495739.2012.720214
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发表时间：
2012-10
影响因子：
2.8
通讯作者：
M. Mirnezhad;M. Modarresi;R. Ansari;M. R. Roknabadi
中科院分区：
文献类型：
--
作者：
M. Mirnezhad;M. Modarresi;R. Ansari;M. R. Roknabadi
材料热机械行为的温度依赖性在许多工程应用中非常重要，这些应用需要材料在扩展温度范围内的精确性能。这项工作的目的是提出密度泛函研究来预测石墨烯杨氏模量的温度变化。为此，声子的能量以及热力学函数是通过准谐波近似从声子计算中计算出来的。据观察，随着应变的增加，声子能量降低。此外，通过将温度升高到 400 K 左右的特定值，杨氏模量会明显降低。对于高于 400 K 的温度，杨氏模量以较低的速率下降，并且在高温下趋于恒定。所得结果与文献中先前报道的实验数据吻合良好。
The temperature dependence of the thermo-mechanical behavior of materials is of great importance in many engineering applications where the precise properties of materials over an extended temperature range are needed. The objective of this work is to present a density functional study to predict the temperature variation of Young's modulus of graphene. To this end, the energies of phonons as well as thermodynamic functions are calculated from phonon calculations via the quasi-harmonic approximation. It is observed that with the increase of strain the phonon energy decreases. Also, by increasing temperature up to a special value which is around 400 K, Young's modulus decreases appreciably. For the temperatures higher than 400 K, Young's modulus decreases with a lower rate and tends to be constant at high temperatures. The results obtained are in a good agreement with the experimental data previously reported in the literature.