The effect of loading methods on the microstructural evolution and degree of strain localization in Cu50Zr50 metallic glass composite nanowires: A molecular dynamics simulation study

In this work, the Cu50Zr50 metallic glass composite nanowire (MGCNW) is subjected to uniaxial tensile, bending, and cyclic deformation. The effect of loading methods on the microstructural evolution and degree of strain localization is investigated. The simulations are performed using molecular dynamics (MD) code. The embedded atom method (EAM) is used to model the interactions between Cu-Zr atoms. The model for the study is created by embedding spherical copper nanocrystallites (diameter = 50 Å) in the Cu50Zr50 metallic glass matrix. Uniaxial tensile simulations have been carried out at strain rates in the range of 106 s-1 to 109 s-1. Three-point bend tests are carried out at different loading rates (1 m/s to 10 m/s). Finally, a strain-controlled cyclic deformation test is carried out at a strain amplitude of 0.02. All the tests are carried out at a temperature of 300 K. Atomic clusters of high shear strain are observed at the yield that later develops into bands with increasing strain. The degree of strain localization is observed to be higher in the bend tests as compared to the tensile and cyclic deformations. Also, it increases with decreasing strain rate. Voronoi polyhedral analysis reveals the breakdown of (0, 0, 12, 0) icosahedral clusters during plastic deformation, which is prominent during tensile deformation.