Bauschinger Effect in Metallic Glass Nanowires under Cyclic Loading

We present a molecular dynamics simulations on fatigue behaviors of model metallic glass nanowires. We found asymmetric hardening in fatigued metallic glass nanowires, which is analogous to the Bauschinger effect commonly observed in metals and polymers. Here both compressioncompression and tension-tension cyclic loading are imposed using straincontrolled loading scheme up to 100 cycles, with the maximum strain of 4%. It was found that, upon compression-compression fatigue tests, the metallic-glass nanowire hardens in compression tests, while softens in tensile tests. However, upon tension-tension cyclic loading, it was found that the metallic-glass nanowire softens in compression tests, while hardens in tensile tests. The observed Bauschinger effect cannot be explained by population variations of preferred short-range orders such as icosahedral clusters, as it was shown to be almost a constant …