Microstructure evolution in the Zr-based bulk metallic glass composites by additions of oxygen

•The Zr-based BMG composites are obtained at high oxygen levels.•The primary Zr particles act as scavengers for both absorbed and intrinsic oxygen.•Oxygen induces the primary Zr particles transformed from ω-Zr+β-Zr to α-Zr.

The effects of oxygen on the microstructure evolution and glass forming ability of the Zr60Ti20Cu5.6Ni4.4Be10 alloy are investigated. The results show that the entire alloys doped with various oxygen levels exhibit type glass composites. With the increase in the oxygen, the precipitated phase changes from ω-Zr+β-Zr to α-Zr. It is worth noting that the oxygen is segregated in these precipitated crystals, the glass matrix contains very low oxygen level and keeps good glass formation. This founding gives us a new clue to avoid the oxygen detrimental to glass formation just by designing appropriate metallic glass composites.