Formation, thermal stability and mechanical properties in Zr-Al-Co bulk glassy alloys

A Zr-Al-Co ternary alloy was investigated in order to clarify the glass-forming ability, thermal stability and mechanical properties. The Zr₅₅Al₂₀Co₂₅ alloy was found to be fabricated in bulk glassy alloy rods with diameters up to at least 2.5 mm. The glassy alloy rod of 2.5 mm in diameter exhibits a large supercooled liquid region of 79 K, followed by a nearly single exothermic peak due to the precipitation of ZrCo + ZrAlCo + Zr₆Al₂Co phases. The glassy alloy rod exhibits Young's modulus of 114 GPa, high compressive fracture strength of 1900 MPa and total fracture elongation of 1.7%. The finding of forming the bulk glassy alloy at the new ternary composition of Zr₅₅Al₂₀Co₂₅ by the copper mold casting method is encouraging for future search of a new glassy alloy composition.