Effects of Al replacement on glass forming ability and mechanical properties of Zr-based bulk metallic glasses

•The effects of Al substitution for Zr in Zr73-xCu12Ni12AlxNb3 (x=7.5, 10, 12.5, 15, 17.5 at.%) metallic glasses on the glass-forming ability, thermal stability, quasi-static and dynamic mechanical properties were investigated.•The Zr58Cu12Ni12Al15Nb3 bulk metallic glass (BMG) with a high strength of 1768MPa and a large plasticity of 2.49% was obtained, which also exhibited the highest glass forming ability (GFA) among the Zr-based BMGs.•Optimization of various properties with appropriate Al substitution for Zr was understood by combining the structural model with experimental results.