Fatigue behaviors of the Cu47.5Zr47.5Al5 bulk-metallic glass (BMG) and Cu47.5Zr38Hf9.5Al5 BMG composite

Based on the Cu47.5Zr47.5Al5 bulk-metallic glass (BMG), the Cu47.5Zr38Hf9.5Al5 BMG composite with a CuZr phase is fabricated successfully. The four-point-bend fatigue behaviors are investigated. The fatigue-endurance limit of the BMG composite is 378 MPa, based on the stress range (σr = σmax − σmin, where σmax and σmin are the applied maximum and minimum stresses, respectively). This value is much higher than that (224 MPa) of the BMG. The fatigue ratios (= the maximum stress range/yield strength corresponding to the fatigue cycles equal to 107) of the BMG composite and the BMG are 0.23 and 0.12, respectively. The different fatigue-fracture surfaces of the BMG and BMG composite show somewhat different fracture mechanisms, which could be rationalized in terms of the effects of the second phase in the composite.