Crack velocities and microstructural investigations in nickel nanowires with crack, crack-defect under mode-I and bending using large-scale molecular dynamics simulations

Crack propagation and crack-defect (void) interactions are investigated in nickel nanowires (NWs) of [010], [1-10], and [111] axial crystallographic orientations by subjecting to tensile loading (mode-I) at a temperature of 10 K and strain rate of 109 s-1. From the molecular dynamic (MD) simulation results, it is observed that crack does not propagate in the [111] orientation NW. The crack velocity is 313 m/s in [010] orientation nickel NW with crack. The predominant deformation mechanisms are slip by Shockley partial dislocation in [010], [111] orientations, and twinning in [1-10] orientation. With the decrease in crack-void spacing from 20 Å to 5 Å, the average crack velocities (207 m/s-120 m/s) decrease in [010] orientation due to crack tip blunting arising from the crack-void coalescence. Three point bending simulations studies carried out on the above mentioned NWs also show similar deformation mechanism features and a decrease in crack velocities from 130 m/s-77 m/s.