A theoretical insight into the fracture behavior of the edge-cracked polycrystalline BC3 nanosheets

Abstract

This work aims to investigate the mechanical and fracture behavior of mono- and polycrystalline BC3 nanosheets (MC- and PCBC3NS) in terms of the number of grain boundaries, status of edge-cracks, and temperature. By using molecular dynamics simulation, appropriate potential function and boundary conditions, MC- and PCBC3NS were modeled and tested varying the temperature and crack length. Results demonstrated that the mechanical properties of MCBC3NSs were decreased as the temperature or the crack length increased, where higher properties were achieved in the armchair direction. Stress intensity variation followed a similar trend upon temperature, but increased as the crack length increased. The minimal elastic modulus, failure stress, and failure strain of the MCBC3NS, for crack length L/2, zigzag direction, and at 1000 K were respectively 53%, 84%, and 75% lower compated to values at 100 K. The same trend was detected for PCBC3NSs upon crack length increase at 300 K, while the properties of PCBC3NSs were lower than the corresponding MCBC3NS. Moreover, for the PCBC3NSs with smaller cracks, both the crack length and grain boundary played key roles in the fracture process, while for large cracked nanosheets the effect of grain boundary was negligible. This work unveiled the fingerprint of the fracture behavior of 2D nanosheets which enlightens future ahead of next generations of nano-devices.