Insight into the nanomechanical properties under indentation of beta- Si3N4 nano-thin layers in the basal plane using molecular dynamics simulation

XF Lu and X Guo and PQ La and YP Wei and XL Nan and L He, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 16, 18858-18865 (2014).

DOI: 10.1039/c4cp02449d

Molecular dynamics simulations were performed to clarify the nanomechanical responses of beta-Si3N4 nano-thin layers in the basal plane for indenters of various radii, different indentation velocities and at different temperatures. It was found that the maximum loading stress and indenter displacement both increase with increasing radius of the indenter. A large number of N-6h-Si bond-breaking defects and one N -2c-Si bond-breaking defects are responsible for the initiation of fracturing. With increasing loading velocity, the maximum loading stresses show almost no change; however, a high loading velocity can shorten the displacement of the indenter and contributes to the formation of new N-2c-Si bond-breaking defects. Thermal fluctuations can decrease the mechanical properties of the thin layer. The maximum loading stresses and indenter displacements are sensitive to both the radius of the indenter and the loading temperature.

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