Fatigue and fracture behavior of bulk metallic glasses and their composites

A fundamental understanding of the fatigue and fracture behavior of bulk metallic glasses (BMGs) and their composites is of critical significance for designing new BMG systems and developing new manufacturing and processing techniques so as to broaden the scope of applications of BMGs and their composites. However, the fatigue and fracture studies on BMGs are limited so far, compared to other mechanical properties. The present work reviews the fatigue and fracture behavior of BMGs and their composites, as well as that of metallic-glass films, ribbons, and wires. The grand challenge for the fatigue and fracture performance of BMGs is: What produces a large difference among the fatigue and fracture results of BMGs? According to the fatigue and fracture investigations of crystalline alloys including recently invented high entropy alloys, many factors could be involved, such as the composition, material quality, specimen geometry, chemical environment, surface condition, temperature, cyclic frequency, mean stress, and residual stress, etc. Based on this challenge, the present work will review and address the factors affecting the fatigue and fracture behavior of BMGs and their composites. Furthermore, the mechanisms of fatigue-crack initiation, propagation, and fracture of BMGs and their composites in different loading conditions and environments will be outlined, analyzed, and discussed. Future research directions of fatigue and fracture of BMGs and their composites are provided for reference.