Fatigue behavior of Zr-based metallic glass micropillars

Abstract Metallic glass with thermoplastic properties in the supercooled liquid region is a potential type of material for fabricating micro molds. Fatigue behavior of metallic glass is the crucial property that enables it to serve as a mold material. Here, fatigue and fracture behaviors of the micro-sized Zr41·2Ti13·8Cu12·5Ni10Be22.5 (at.%, Vit1) metallic glass micropillars were investigated by uniaxial compression-compression fatigue tests. It was shown that the micropillars have fatigue–endurance limit of ~1000 MPa and a fatigue ratio of ~0.56. The effects of sample size and heat treatment on the fatigue limit were also studied. After annealing at 450 °C, the fatigue limit decreased to ~600 MPa and the fatigue ratio decreased to ~0.43. The fracture angles between the stress axis and the shear plane of unannealed metallic glass were found to be ~42°, while the annealed Vit1 micropillars failed in break or splitting modes. These findings provided the experimental evidence for the inhomogeneous structure and the size effect in metallic glass failure modes at the micro-scale size. Our results can serve as a guideline for further studies to investigate the mechanical behavior and deformation mechanisms of the metallic glass.