Fatigue behaviors of the Cu_(47.5)Zr_(47.5)A1_5 bulk-metallic glass (BMG) and Cu_(47.5)Zr_(38)Hf_(9.5) Al_5 BMG composite

摘要

Based on the Cu_(47.5)Zr_(47.5)Al_5 bulk-metallic glass (BMG), the Cu_(47.5)Zr_(38)Hf_(9.5)Al_5 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 (σ_x = σ_(max) - σ_(max), where σ_(max) and σ_(max) 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.