In Situ Tensile Testing of Nanometer-Thick Two-Dimensional Transition-Metal Carbide Films: Implications for MXenes Acting as Nanoscale Reinforcement Agents
In Situ Tensile Testing of Nanometer-Thick Two-Dimensional Transition-Metal Carbide Films: Implications for MXenes Acting as Nanoscale Reinforcement Agents
复制标题
DOI：
10.1021/acsanm.1c00537
复制
发表时间：
2021-05
期刊：
影响因子：
--
通讯作者：
Yanxiao Li;Congjie Wei;Shuohan Huang;Arman Ghasemi;Wei Gao;Chenglin Wu;V. Mochalin
中科院分区：
文献类型：
--
作者：
Yanxiao Li;Congjie Wei;Shuohan Huang;Arman Ghasemi;Wei Gao;Chenglin Wu;V. Mochalin
利用原位扫描电子显微镜（SEM）纳米压痕仪和推挽式（PTP）微机电系统（MEMS），研究了TiC MXene（Ti2CTx，Ti3C2Tx）叠层材料的面内力学行为。当堆叠中的MXene单层的数量从9到26（Ti2CTx，间距为1.36 nm）和7到52（Ti3C2Tx，间距为1.48 nm）变化时，测量的杨氏模量几乎保持恒定，平均为217.75 GPa（Ti2CTx）和204.92 GPa（Ti3C2Tx）。在相同的实验中，测得的拉伸强度从9.61 GPa（Ti2CTx）单调降低到7.59 GPa（Ti3C2Tx）和从9.89 GPa单调降低到7.99 GPa（Ti3C2Tx）。值得注意的是，这种对堆叠的MXene单层数量的依赖性比先前在多层石墨烯和MoS2堆叠中观察到的要弱得多，随着单层数量的增加，与从加和性所预期的相比，其显示出拉伸强度和杨氏模量的显著降低。这种差异意味着与其他多层二维（2D）材料相比，MXene的机械性能更好地按比例放大。此外，原子模拟表明，在多层MXene中的不同层中的缺陷引起所观察到的拉伸强度对堆叠中的MXene单层的数量的依赖性。在具有最高缺陷密度的最弱层中引发的原子损伤促进应变软化，导致MXene的拉伸强度降低。我们的研究结果表明，多层MXenes可用作各种规模的复合材料的优异机械增强剂，并可能用于其他需要强大机械性能的应用。
In-plane mechanical behavior of stacks formed by titanium carbide MXenes (Ti2CTx, Ti3C2Tx) was investigated in a microscale uniaxial tensile experiment with thein situscanning electron microscope (SEM) nanoindenter and a push-to-pull (PTP) micro-electro-mechanical system (MEMS). When the number of MXene monolayers in a stack varies from 9 to 26 (Ti2CTxwithd-spacing of 1.36 nm) and 7 to 52 (Ti3C2Txwithd-spacing of 1.48 nm), the measured Young’s moduli stay almost constant, averaging at 217.75 GPa (Ti2CTx) and 204.92 GPa (Ti3C2Tx). In the same experiment, the measured tensile strength monotonically decreases from 9.61 to 7.59 GPa (Ti2CTx) and 9.89 to 7.99 GPa (Ti3C2Tx). Notably, this dependence on the number of stacked MXene monolayers is much weaker than that previously observed in multilayer graphene and MoS2stacks, which displayed a significant reduction of both tensile strength and Young’s modulus, compared to what was expected from additivity, as the number of monolayers increased. This difference implies a better scaling-up of the mechanical properties of MXenes as compared to other multilayer two-dimensional (2D) materials. Furthermore, atomistic simulations show that defects in different layers in the multilayer MXenes give rise to the observed dependence of the tensile strength on the number of MXene monolayers in a stack. The atomic damage initiated in the weakest layer with the highest defect density promotes strain softening, leading to a reduced tensile strength of the MXenes. Our results show that multilayer MXenes could be used as excellent mechanical reinforcing agents for composite materials across scales and potentially in other applications where robust mechanical performance is essential.