Compression-compression fatigue behavior of a Zr-based metallic glass with different free volume contents

The fatigue behaviors of two batches of Zr52.5Cu17.9Ni14.6Al10Ti5 (Vit-105) metallic glasses (MGs) made by different operators in the same laboratory and thereby different free volume contents were investigated under cyclic compression. The difference in initial microstructure is also reflected by the elastic limit and plasticity as well as the shear-band activity under uniaxial compression. It is found that the MG samples with lower free volume content possess enhanced fatigue endurance limit and fatigue ratio, which are highest among all the previously reported fatigue results of Vit-105 MG. The improved fatigue properties can be attributed to the suppression of shear band formation and thus the increase of the resistance to fatigue damage and failure, as evidenced by the much lower shear-band density near the fatigue fracture surface. The fatigue fracture mechanism of MG under cyclic compression is further clarified, based on the ellipse criterion. The present results not only demonstrate the strong sensitivity of fatigue behavior to the initial microstructure of MGs, but also offer a guideline for designing MGs with excellent fatigue performance through tailoring microstructure and controlling shear banding behavior. (C) 2019 Elsevier B.V. All rights reserved.