Abstract As a newly discovered two-dimensional (2D) material group, MXene has exceptional thermal- electronic properties. However, its mechanical behavior, especially fracture, remains unexplored. In-situ SEM tensile experiments show that the fracture of MXene is quite nonlinear with a much-prolonged softening stage in comparison with other 2D materials, which is suspected to be caused by the anisotropy and relatively thick monolayer of MXenes. In this work, molecular dynamic (MD) modeling is conducted to investigate the anisotropic fracture behavior of two types of MXenes (Ti2C and Ti3C2) with different monolayer thickness. Both pristine and defected MXenes are investigated. Results show that: (1) MXene tends to fracture along zigzag direction, (2) atomic vacancies at the crack tip have limited effects on the overall fracture behavior, (3) a thicker monolayer can produce a larger cohesive zone due to the ‘thinning’ process, (4) complex fracture paths are to be expected for mixed-mode fractures.

中文翻译：

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二维过渡金属碳化物 (MXenes) 的非线性断裂

摘要 作为新发现的二维 (2D) 材料群，MXene 具有卓越的热电子特性。然而，它的力学行为，尤其是断裂，仍然有待探索。原位 SEM 拉伸实验表明，与其他二维材料相比，MXene 的断裂非常非线性，软化阶段延长很多，这可能是由 MXene 的各向异性和相对较厚的单层引起的。在这项工作中，进行分子动力学（MD）建模以研究具有不同单层厚度的两种类型的 MXenes（Ti2C 和 Ti3C2）的各向异性断裂行为。研究了原始和有缺陷的 MXene。结果表明：（1）MXene倾向于沿Z字形方向断裂，（2）裂纹尖端的原子空位对整体断裂行为的影响有限，