Graphene Foam: Uniaxial Tension Behavior and Fracture Mode Based on a Mesoscopic Model
Graphene Foam: Uniaxial Tension Behavior and Fracture Mode Based on a Mesoscopic Model
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石墨烯泡沫：基于细观模型的单轴拉伸行为和断裂模式
DOI：
10.1021/acsnano.7b03474
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发表时间：
2017-09-01
期刊：
影响因子：
17.1
通讯作者：
Yao, Yugui
中科院分区：
文献类型：
--
作者：
Pan, Douxing;Wang, Chao;Yao, Yugui
由于多孔材料和二维（2D）石墨烯片两者的组合优点，三维（3D）石墨烯泡沫的上级机械性能受到材料科学家和能源工程师的广泛关注。这里，2D介观石墨烯模型（Modell. Simul Mater. Sci. Eng.2011，19，054003），通过考虑脱粘行为，利用物理交联和作用在不同介观石墨烯薄片之间的货车德瓦尔斯力，扩展成3D结合的石墨烯泡沫体系，以基于原位SEM拉伸测试（Carbon 2015，85，299）评估单轴拉伸行为和断裂模式。我们合理地再现了一个多峰应力应变关系，包括其明显的屈服平台和韧性断裂模式附近的45平面从拉伸方向，包括相应的断裂形态。在此基础上，推导了拉伸弹性模量与质量密度的幂次标度律和各向异性应变相关泊松比。通过局部应力状态和细观结构的演变，揭示了拉伸变形的细观物理机制。结合石墨烯泡沫的断裂特征及其热力学状态，直接导航到介观石墨烯片的撕裂模式。该研究为理解三维石墨烯泡沫的介观物理性质提供了一种有效的方法，因此它可能有助于微/介观/宏观力学性能的多尺度计算和先进石墨烯泡沫基材料的优化设计。
Because of the combined advantages of both porous materials and two-dimensional (2D) graphene sheets, superior mechanical properties of three-dimensional (3D) graphene foams have received much attention from material scientists and energy engineers. Here, a 2D mesoscopic graphene model (Modell. Simul. Mater. Sci. Eng. 2011, 19, 054003), was expanded into a 3D bonded graphene foam system by utilizing physical cross-links and van der Waals forces acting among different mesoscopic graphene flakes by considering the debonding behavior, to evaluate the uniaxial tension behavior and fracture mode based on in situ SEM tensile testing (Carbon 2015, 85, 299). We reasonably reproduced a multipeak stress strain relationship including its obvious yielding plateau and a ductile fracture mode near 45 plane from the tensile direction including the corresponding fracture morphology. Then, a power scaling law of tensile elastic modulus with mass density and an anisotropic strain-dependent Poisson's ratio were both deduced. The mesoscopic physical mechanism of tensile deformation was clearly revealed through the local stress state and evolution of mesostructure. The fracture feature of bonded graphene foam and its thermodynamic state were directly navigated to the tearing pattern of mesoscopic graphene flakes. This study provides an effective way to understand the mesoscopic physical nature of 3D graphene foams, and hence it may contribute to the multiscale computations of micro/meso/macromechanical performances and optimal design of advanced graphene-foam-based materials.