To determine the optimized composition of quaternary Zr-Cu-Ni-Al bulk glassy alloy, its thermal and mechanical properties are examined. Zr shows high correlation coefficients with T g and Vickers hardness, whereas Ni and Al show high correlation coefficients with T l and T x , respectively. Only Cu shows no remarkable correlation coefficient with any thermal or mechanical properties. We conclude that a compositional region with a high (over 135 kJ/m 2 ) U-notch Charpy impact (CUE) value is located around the Zr 52 Cu 30 Ni 8 Al 10 bulk glassy alloy, which exhibits a maximum CUE of 165 kJ/m 2 . Moreover, a compositional region with high tensile strength (over 2000 MPa) is also located around the Zr 48 Cu 32 Ni 8 Al 12 bulk glassy alloy, which shows a maximum tensile strength of 2100 MPa
