부산대학교 도서관

A metastable in situ dendrite Ti-based metallic glass composite (MGC) with an excellent combination of strength, ductility, and work-hardening ability was recently reported. In this work, the tension–tension fatigue behavior of this MGC was investigated for a deep understanding of its overall mechanical property. The stress–life (S–N) data indicated that the fatigue endurance limit of the current MGC was ~ 120 MPa based on the stress amplitude. The fatigue mechanism was revealed by analyzing the microstructural and damage features with X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The slipping deformation dominated the fatigue deformation, and the fatigue crack tended to initiate within the dendrite phase and along the dendrite–matrix interface. By the repeated coalescence of microcracks ahead of the fatigue crack tip, the crack propagated through the metallic glass matrix and dendrites in a straight manner. In addition, it was also found that the martensite laths were generated within the dendrites under high stress levels. Finally, the influence of the loading mode on the fatigue behavior of this MGC was compared in combination with previous data. For the present composition, the fatigue limit under four-point bending fatigue loading was almost three times as high as that under tension–tension fatigue loading, and the reasons for the large discrepancy were clarified.Graphical Abstract: