Effects of loading mode and orientation on deformation mechanism of graphene nano-ribbons

Molecular dynamics simulation is performed to analyze the deformation mechanism of graphene nanoribbons. When the load is applied along the zigzag orientation, tensile stress yields brittle fracture and compressive stress results in lattice shearing and hexagonal-to-orthorhombic phase transformation. Along the armchair direction, tensile stress produces lattice shearing and phase transformation, but compressive stress leads to a large bonding force. The phase transformation induced by lattice shearing is reversible for 17% and 30% strain in compressive loading along the zigzag direction and tensile loading along the armchair direction. The energy dissipation is less than 10% and resulting pseudo-elasticity enhances the ductility.