Nickel–Cobalt Core–Shell Nanowires Under Uniaxial Tensile Loading—A Molecular Dynamics Modeling Analysis

One-Dimensional nanostructures are of great importance due to their unique electrical, magnetic and mechanical properties. Because of the size constraints, it is impractical to obtain and understand their mechanical properties, deformation behavior and associated mechanisms experimentally, while atomistic computational modeling offers a viable approach. Several studies have focused on pure metallic and compound nanowires; however, investigations and data for core–shell nanowires is still very limited. Present work models and analyzes Nickel–Cobalt (Ni–Co) core–shell nanowire systems under uniaxial tensile loading via molecular dynamics (MD) modeling. Present studies and analysis focus on predictive mechanical properties as well as insights on deformation mechanisms and dislocations during uniaxial tensile loading. Further, pure Ni and Co nanowire systems of similar configurations are modeled, and compared to our findings of core–shell nanowire systems. Results indicate that crystal mismatch in the region of core–shell interface have a significant effect, and plays an important role in the deformation process. Evolution of dislocations during uniaxial tensile loading deformation process, following a dislocation extraction analysis are presented and discussed. Further investigations of the core–shell nanowire structures involved a systematic study on the effect of core size on the predicted mechanical properties. Results indicate that the yield strength and Young's modulus indicated a linear increase for nickel shell–cobalt core systems with a Cobalt core for increasing core sizes, while maintaining nearly similar volume, length, and outer diameter of the core–shell nanowire system. Cobalt shell–nickel core nanowire systems with nickel core however was found not to depict any such definitive characteristics.