Inter-granular fracture behaviour in bicrystalline boron nitride nanosheets using atomistic and continuum mechanics-based approaches

Abstract

Hexagonal boron nitride nanosheets (BNNS) are among the emerging nanomaterials with potential application in water purification, nanocomposites and ion separation. In this article, atomistic followed by sequential multiscale models in the framework of finite element was developed to investigate the inter-granular fracture properties of bicrystalline BNNS. Atomistic simulations were performed in the environment of classical mechanics-based molecular dynamics to capture the crack tip behaviour, and for developing traction separation law for bicrystalline BNNS. Moreover, the fracture toughness of bicrystalline BNNS is significantly dependent on the misorientation angle, GB configuration in terms of homoelemental bonds (B–B or N–N) and orientation of loading. The average crack propagation velocity was calculated at atomistic scale and was made to compare with the value predicted using linear elastodynamic theory. The average crack tip stresses predicted from atomistic simulations were found to be in good agreement with values calculated from the continuum model developed using the principle of sequential multiscale model. This work provides a systematic study of inter-granular fracture in bicrystalline BNNS, providing valuable information to develop future applications of 2D nanosheets.