Large-Scale Molecular Dynamics Simulation Studies on Deformation of Ni Nanowires: Surface Profile, Defects and Stacking Fault Width Analysis

We report large-scale molecular dynamics simulation deformation studies of Ni nanowire (NW) of size 100 A (x) × 1000 A (y) × 100 A (z) comprising of 925,965 atoms. Surface and internal defects are introduced to study their effect on the surface profile, strength, fracture behavior and deformation mechanisms. Tensile tests have been carried out at a temperature of 10 K and at a strain rate of 108 s−1. Periodic boundary condition is applied along the loading direction (y). Peak strength of 23 GPa is observed in the perfect NW, and the strength decreases with defects. The surface profiles of the deformed NWs show intrusion and extrusion regions corresponding to slip steps with wider valleys in the defect NWs. Several intrinsic and extrinsic parallel stacking faults (SFs) are generated after yielding by slip occurring on {111} planes. The calculated SF widths are in the range of 0.85-2.57 nm in the perfect NW. The dislocations are mainly Shockley partial dislocations of type 1/6 $$\left\langle {112} \right\rangle$$ , and Schmid’s factor (m) obtained is 0.471. Twinning dislocation of types 1/9 $$\left\langle {221} \right\rangle$$ and 1/18 $$\left\langle {172} \right\rangle$$ is also observed in the SFs. The density of Shockley partial dislocations is observed to be the maximum in all the NWs.