Mechanical properties of AgCo nanostructured nanowires

The mechanical deformation properties of nanostructured AgCo nanowires were studied by Molecular Dynamics (MD) under uniaxial tensile and compressive stresses. The cohesion of the immiscible AgCo system was modeled by an Embedded Atom Model (EAM). Crystalline Co grains were embedded into a Ag crystalline matrix and the whole system was set to relax by MD at 300 K. The Ag crystal structure turned out to be unstable and to transform into the same layered structure as was already predicted in AgCo nanoclusters and AgCo Cluster Assembled Materials (CAM). Deformation was modeled by varying the length of the nanowire in the axial direction. Both isothermal and isoenergetic—whereby mechanical work converts into heat in the system—deformation mechanisms were considered. In contrast with the case of AgCo CAM where an elastic regime was identified, deformation of AgCo nanowires was never found fully elastic, whatever the magnitude of the deformation. In case of constant temperature deformation, Ag kept its layered structure and the Co grains kept crystalline. At constant energy, as a consequence of the rise of temperature, phase separation and melting took place whereby a coaxial structure was formed with the Co covered by Ag.