Study of the structural defects on carbon nanotubes in metal matrix composites processed by severe plastic deformation
Study of the structural defects on carbon nanotubes in metal matrix composites processed by severe plastic deformation
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DOI：
10.1016/j.carbon.2017.09.075
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发表时间：
2017-12-01
期刊：
影响因子：
10.9
通讯作者：
Suarez, Sebastian
中科院分区：
文献类型：
--
作者：
Aristizabal, Katherine;Katzensteiner, Andreas;Suarez, Sebastian
碳纳米管（CNT）最近已被提出作为稳定剂对晶粒生长，甚至可以发生在低温输入的纳米晶体和超细晶粒材料通过严重的塑性变形。在这项研究中，我们分析了在碳纳米管增强镍基复合材料与不同的增强重量分数的纳米管上的结构缺陷的演变。采用高压扭转法制备了复合材料，并以拉曼光谱为主要表征手段。结果表明，对于CNT进行高能处理，这是不够的，只分析ID/IG比（如现有文献中提出的），但它也是必要的，以评估G带的移动，其跟踪的CNT经历的非晶化轨迹。此外，我们观察到，碳纳米管所遭受的变形是相关的累积应变，并与这些复合材料的部分碳纳米管分数的变化。这与它们承受变形过程中发生的塑性应变的能力有关。此外，缺陷状态在微观结构细化中达到饱和之前达到饱和。这些结果将有助于有效地优化这类工程复合材料的加工。(C)2017爱思唯尔有限公司版权所有
Carbon nanotubes (CNT) have been recently proposed as stabilizers against grain growth that can happen even at low temperature inputs in nano-crystalline and ultrafine-grained materials obtained by severe plastic deformation. In this study, we analyzed the evolution of the structural defects on the nanotubes in CNT-reinforced nickel matrix composites with different reinforcement weight fractions. The composites were processed by high pressure torsion, and we used Raman spectroscopy as the main characterization technique. The results indicate that for CNT subjected to highly energetic processing, it is not sufficient to analyze only the ID/IG ratio (as proposed in the available literature), but it is also necessary to evaluate the shifting of the G band, which traces the amorphization trajectory undergone by the CNT. Furthermore, we observed that the deformation suffered by the CNT is related to the accumulated strain and varies with the partial CNT fractions of these composites. This is related to their capacity to withstand the plastic strain that occurs during deformation. In addition, the defective state reaches a saturation before achieving the saturation in the microstructural refinement. These results will help to efficiently optimize the processing of this type of engineering composites. (C) 2017 Elsevier Ltd. All rights reserved.