Molecular dynamics simulation on mechanical behaviors of Ni_xAl_100-x nanowires under uniaxial compressive stress

This article investigates the nanoscale mechanical properties and deformation mechanism of Ni_x-Al_100-x metallic glasses nanowires (NWs) subjected to uniaxial compressive stress. Molecular dynamics (MD) simulation is carried out using the program package LAMMPS with Embedded-Atom potential. Simulation is performed and focused on the effects of different slenderness ratio, quenching rate, alloy ratio, compression rate, temperature, defects and fracture process of Ni_x-Al_100-x metallic glasses NWs on the mechanical behaviors of these materials. Simulation results show that three possible deformation mechanisms, namely compressive deformation, buckling of structural instability, and lateral extrudes, may occur under different conditions. When the quenching rate is slow, the formation of amorphous phase after quenching is low, but both the corresponding ultimate stress and the Young's modulus become high. Moreover, under the same quenching rate, the ultimate stress increases with the decrease of the slenderness ratio. For different alloy ratio, it is found that B2 phase of this alloy system exhibits the highest magnitude of both ultimate stress and Young's modulus. In addition, the concentration effects of point defects on mechanical behaviors of materials are also evaluated and discussed.