The influence of nanoscale defects on the fracture of multi-walled carbon nanotubes under tensile loading
The influence of nanoscale defects on the fracture of multi-walled carbon nanotubes under tensile loading
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DOI：
10.1016/j.diamond.2010.01.045
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发表时间：
2010-07-01
影响因子：
4.1
通讯作者：
Ruoff, Rodney S.
中科院分区：
文献类型：
--
作者：
Yamamoto, Go;Suk, Ji Won;Ruoff, Rodney S.
我们报道了一种独特类型的多壁碳纳米管(MWCNT)和这种MWCNT类型的酸处理版本的机械行为，它们的表面由于酸处理而具有纳米级的缺陷。从扫描电子显微镜(SEM)和透射电子显微镜(TEM)成像来看，这些缺陷具有通道状的外观，就像从MWCNT周围切下一环的材料一样。实验表明，单个多壁碳纳米管的力学性能强烈依赖于其结构，而结构无序会显著降低其力学性能。使用扫描电子显微镜中的纳米操纵器进行的拉伸加载实验显示，10个原始的多壁碳纳米管的拉伸强度从类似于2到类似于48 Gpa(平均20 Gpa)。对于10个具有通道样缺陷的酸处理多壁碳纳米管，拉伸强度从接近1到接近18 Gpa(平均为6 Gpa，大约比未处理的多壁碳纳米管低70%)。显微结构观察表明，在10个样品中，有8个样品经酸处理后的多壁碳纳米管的断裂发生在沟道状缺陷区。这表明，与酸腐蚀相关的沟道状缺陷通常将是酸处理的MWCNT结构中最薄弱的部分，并且在缺陷区域存在应力集中。(C)2010年，爱思唯尔出版。
We report the mechanical behavior of a unique type of multi-walled carbon nanotube (MWCNT) and an acid-treated version of this MWCNT type that have nanoscale defects on their surfaces from the acid treatment. These defects, from scanning electron microscope (SEM) and transmission electron microscope (TEM) imaging have a 'channel-like' appearance, as if a ring of material was cut away from the MWCNT around the circumference. The mechanical properties of individual MwCNTs have been experimentally shown to strongly depend on their structure and structural disorder can drastically reduce the mechanical properties. Tensile-loading experiments using a nanomanipulator tool operated inside a SEM revealed that the tensile strengths of 10 pristine MWCNTs ranged from similar to 2 to similar to 48 GPa (mean 20 GPa). For 10 acid-treated MWCNTs with channel-like defects, tensile strengths ranged from similar to 1 to similar to 18 GPa (mean 6 GPa, thus roughly 70% lower than those of the pristine MWCNTs). Microstructural observations revealed that the fracture of the acid-treated MWCNTs occurred at a channel-like defect region in 8 of the 10 samples. This indicates that the channel-like defects associated with the acid etching are typically going to be the weakest points in the acid-treated MWCNT structure and that stress concentration is present at the defect region. (C) 2010 Published by Elsevier B.V.