Dynamic behaviour of silicon carbide nanowires under high and extreme strain rates: a molecular dynamics study

Abstract

Molecular dynamics simulations are used to investigate the dynamic behaviour of SiC nanowires under strain rates between 2 × 10 9 s −1 and 2 × 10 11 s −1 . Nanowires of different cross sections in the wurtzite (WZN) and zinc blende (ZBN) phases are considered under tensile and compressive deformation. Results show contrasts and similarities in the behaviour of WZNs and ZBNs for the lowest strain rate. (i) WZNs present a continuous structural transformation in the elastic regime under compressive deformation, to a h-MgO structure, while ZBNs display a similar kind of transformation to the β-Sn structure under tensile deformation. (ii) Under tensile deformation WZNs fail by brittle fracture while ZBNs display complex plasticity before failure. (iii) Under compressive deformation both ZBNs and WZNs show buckling and plasticity. For the highest strain rate the mechanical behaviour is similar: both WZNs and ZBNs show induced amorphization for both tensile and compressive deformations.