Fatigue behaviors of the Cu47.5Zr47.5Al5 bulk-metallic glass (BMG) and Cu47.5Zr38Hf9.5Al5BMG 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 (sigma(r) = sigma(max) - sigma(min), where sigma(max) and sigma(min) 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 10(7)) 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. (C) 2007 Elsevier Ltd. All rights reserved.