Computational Materials Science ( IF 3.3 ) Pub Date : 2021-08-19 , DOI: 10.1016/j.commatsci.2021.110770 Fatemeh Molaei 1 , Maryam Zarghami Dehaghani 2 , Azam Salmankhani 3 , Sasan Fooladpanjeh 4 , S. Mohammad Sajadi 5, 6 , Mohammad Esmaeili Safa 7 , Otman Abida 8 , Sajjad Habibzadeh 9 , Amin Hamed Mashhadzadeh 10 , Mohammad Reza Saeb 11
Graphene-like nanosheets are the key elements of advanced materials and systems. The mechanical behavior of the structurally perfect 2D nanostructures is well documented, but that of polycrystalline ones is less understood. Herein, we applied molecular dynamics simulation (MDS) to take the fracture fingerprint of polycrystalline SiC nanosheets (PSiCNS), where monocrystalline SiC nanosheets (MSiCNS) was the reference nanosheet. The mechanical responses of defect-free and defective MSiCNS and PSiCNS having regular cracks and circular-shaped notches were captured as a function of temperature (100–1200 K), such that elevated temperatures were unconditionally deteriorative to the properties. Moreover, larger cracks and notches more severely decreased the strength of PSiCNS, e.g. Young’s modulus dropped to ca. 41% by the crack enlargement. The temperature rise similarly deteriorated the failure stress and Young's modulus of PSiCNS. However, the stress intensity factor increased by the enlargement of the crack length but decreased against temperature. We believe that the findings of the present study can shed some light on designing mechanically stable nanostructures for on-demand working conditions.
中文翻译:
应用分子动力学模拟获取多晶 SiC 纳米片的断裂指纹
类石墨烯纳米片是先进材料和系统的关键元素。结构完美的 2D 纳米结构的机械行为有据可查,但多晶纳米结构的机械行为却鲜为人知。在此,我们应用分子动力学模拟 (MDS) 来获取多晶 SiC 纳米片 (PSICNS) 的断裂指纹,其中单晶 SiC 纳米片 (MSICNS) 是参考纳米片。具有规则裂纹和圆形缺口的无缺陷和有缺陷的 MSiCNS 和 PSiCNS 的机械响应被捕获为温度 (100-1200 K) 的函数,因此升高的温度会无条件地降低性能。此外,较大的裂纹和缺口更严重地降低了 PSiCNS 的强度,例如杨氏模量下降到大约 41% 由裂纹扩大。温度升高同样使 PSiCNS 的失效应力和杨氏模量恶化。然而,应力强度因子随着裂纹长度的增大而增加,但随着温度的升高而减小。我们相信,本研究的结果可以为按需工作条件设计机械稳定的纳米结构提供一些启示。