Formation, thermal and mechanical properties of bulk glassy alloys in Zr-Al-Co and Zr-Al-Co-Cu systems

New Zr-based bulk glassy alloys in Zr-Al-Co and Zr-Al-Co-Cu systems were developed. The largest supercooled liquid region is upto 64 K for the Zr₅₅Al₂₀Co₂₅ alloy and 80 K for the Zr₅₅Al₂₀Co₂₀ Cu₅ alloy, respectively. Glassy rods with a diameter of 3 mm for the Zr₅₅Al₂₀Co₂₅ alloy and 5 mm for the Zr₅₅Al₂₀Co₂₀Cu₅ alloy can be prepared by copper-mold casting. Glassy Zr₅₅Al₂₀Co₂₀Cu₅ sheet with a thickness of 2 mm was also formed by squeeze copper-mold casting. The bulk glassy Zr₅₅Al₂₀Co₂₀ Cu₅ alloy exhibits Young's modulus of 92 GPa, elastic limit of 2.1%, tensile strength of 1960 MPa, compressive fracture strength of 2200 MPa, and compressive plastic strain of 0.6%. The tensile strength value is considerably higher than those for the other Zr-based bulk glassy alloys reported upto date. The synthesis of the new Zr-based bulk glassy alloys with high glass-forming ability and high tensile strength approaching 2000 MPa is expected to result in a future extension of application fields as a high strength material.