Synthesis and compressive fracture behavior of a CuZr-based bulk amorphous alloy with Ti addition

CHEN Ding(陈鼎), DONG Jian-feng(董建峰), MA Guo-zhi(马国芝)

(College of Materials Science and Engineering, Hunan University, Changsha 410082, China)

Abstract:Cu₄₆Zr₄₆Al_4.8Ti_3.2 bulk metallic glass (BMG) was successfully synthesized by copper-mold casting and the mechanical properties at room temperature were measured by compression tests. The structure and thermal characteristics were analyzed by XRD and DSC, and the fracture surface morphology was examined by SEM. The glassy alloy with 4 mm in diameter shows an high fracture strength of 1 960 MPa, with an improvement of about 20% compared to the ultimate compression fracture strength of the Cu₄₆Zr₄₆Al₈ BMG, which suggests that the Ti addition improves the compression fracture strength. The different degrees of the adiabatic heating induce four types of fracture features: a vein-like structure, an elongated and striated vein pattern, melting and smooth regions. The elongated and striated vein patterns as well as the melting region show that enormous strain energy is released, which causes significant adiabatic heating. Furthermore, many micro-cracks observed in the smooth region are caused by the strong shear force. In addition, the strong shear force leads to many shear bands as well as the melting in the lateral surface.

Key words:Cu-Zr-Ti-Al bulk metallic glass; compression fracture behavior; fracture morphology; adiabatic heating