Shear mechanical property of β-Si3N4 nano-thin layers in the basal plane using molecular dynamics simulations

Molecular dynamics simulations are performed to clarify the shear mechanical property of β-Si3N4 nano-thin layer in the basal plane with different extreme strain rates and loading temperatures. The thin layer displays nonlinear and linear response stress-strain relationships, and fracture stresses and strains increase gradually with increasing the strain rates, which is attributed to the appearance of a great quantity of single nitrogen atom and “turtle-like” hexagon defects. With increasing loading temperature, there is a noticeable drop in both fracture stress and fracture strain. In the higher loading temperature range, the lower fracture stresses are obtained owing to the disappearance of defects mentioned above, which can be also elaborated by a combination of factors such as the appeared N6h-Si bond breaking alone in configuration evolution and the accompanied lower total energy.