Effect of uniaxial loading on the structural anisotropy and the dynamics of atoms of Cu 50Zr 50 metallic glasses within the elastic regime studied by molecular dynamics simulation

Abstract

The changes in the structure and dynamics of atoms and the stress-induced structural anisotropy of a Cu 50Zr 50 metallic glass upon the application of uniaxial compressive and tensile stresses within the elastic regime during the loading and unloading processes have been studied using molecular dynamics simulation. The structural change is found to be more significant under tension than under compression, which is accompanied with the destruction of the full icosahedra clusters into distorted ones. Permanent structural change is found at the applied tensile stress of 1000 MPa but is still within the elastic regime. The fabric tensor and bond number analysis reveals that the structural anisotropy increases monotonously with the applied stress, being more pronounced along the loading direction than in the other two free directions. The results of the mean square displacement, the non-Gaussian parameter and the mobile atom analysis suggest that the dynamics of the atoms are distinctly different under uniaxial stresses above 800 MPa. The α-relaxation occurs more easily under tension than under compression as the applied stresses exceed 800 MPa. The permanent change in the structure and structural anisotropy could be correlated with the change in the dynamics of the atoms.