Rong Chao, Su Ting, Li Zhenkai, Chu Tianshu, Zhu Mingliang, Yan Yabin, Zhang Bowei, Xuan Fu-Zhen
Shanghai Key Laboratory of Intelligent Sensing and Detection Technology, East China University of Science and Technology, Shanghai, 200237, P. R. China.
Key Laboratory of Pressure Systems and Safety of Ministry of Education, East China University of Science and Technology, Shanghai, 200237, P. R. China.
Nat Commun. 2024 Feb 21;15(1):1566. doi: 10.1038/s41467-024-45657-6.
Two-dimensional (2D) transition metal nitrides and carbides (MXenes), represented by TiCT, have broad applications in flexible electronics, electromechanical devices, and structural membranes due to their unique physical and chemical properties. Despite the Young's modulus of 2D TiCT has been theoretically predicted to be 0.502 TPa, which has not been experimentally confirmed so far due to the measurement is extremely restricted. Here, by optimizing the sample preparation, cutting, and transfer protocols, we perform the direct in-situ tensile tests on monolayer TiCT nanosheets using nanomechanical push-to-pull equipment under a scanning electron microscope. The effective Young's modulus is 0.484 ± 0.013 TPa, which is much closer to the theoretical value of 0.502 TPa than the previously reported 0.33 TPa by the disputed nanoindentation method, and the measured elastic stiffness is ~948 N/m. Moreover, during the process of tensile loading, the monolayer TiCT shows an average elastic strain of ~3.2% and a tensile strength as large as ~15.4 GPa. This work corrects the previous reports by nanoindentation method and demonstrates that the TiCT indeed keeps immense potential for broad range of applications.
以TiCT为代表的二维（2D）过渡金属氮化物和碳化物（MXenes），因其独特的物理和化学性质，在柔性电子器件、机电设备和结构膜等领域有着广泛的应用。尽管二维TiCT的杨氏模量在理论上预测为0.502太帕，但由于测量极其受限，目前尚未得到实验证实。在此，通过优化样品制备、切割和转移方案，我们使用扫描电子显微镜下的纳米力学推挽设备对单层TiCT纳米片进行了直接原位拉伸试验。有效杨氏模量为0.484±0.013太帕，比之前有争议的纳米压痕法报道的0.33太帕更接近理论值0.502太帕，且测得的弹性刚度约为948牛/米。此外，在拉伸加载过程中，单层TiCT显示出约3.2%的平均弹性应变和高达约15.4吉帕的拉伸强度。这项工作纠正了之前纳米压痕法的报道，并证明TiCT在广泛的应用领域确实具有巨大潜力。
