Effect of interfacial bonding on dislocation strengthening in graphene nanosheet reinforced iron composite: A molecular dynamics study

L Wang and JF Jin and PJ Yang and SJ Li and SA Tang and YP Zong and Q Peng, COMPUTATIONAL MATERIALS SCIENCE, 191, 110309 (2021).

DOI: 10.1016/j.commatsci.2021.110309

It is uncertain that the interfacial bonding is whether a strong chemical bond or a weak van der-Waals one in graphene-metal composites. The effect of interfacial bonding features on dislocation strengthening are still obscure. Herein, we have investigated the mechanical response and dislocation behaviors of graphene/Fe composite using molecular dynamics simulations. Lennard-Jones and embedded-atom typed potential is employed to model a weak and strong interfacial bonding, respectively. We have considered anisotropy in three cases where a pair of graphene nanosheet (GN) were placed on three orthogonal (110, 111 and 112) plane. When the dislocation is directly blocked by the GN, the yield stress of the strong-bonded composite is higher than that of the weak- bonded one. After the dislocation depins from the strong-bonded 112 GN, the Orowan loop is formed without surface step, in contrast to that in the weak-bonded one. For the 111 GN/Fe, the dislocation bypasses the GN pair in the strong-bonded composite, where double cross-slip and dislocation neutralization on the top 110 slip plane occur opposed to the middle 110 plane in the weak-bonded case.

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