Toughness of Zr55Cu30Al10Ni5 bulk metallic glass for two oxygen levels

This paper demonstrates the embrittlement of a Zr-based bulk metallic glass caused by the presence of very low oxygen traces during its synthesis. Toughness studies are conducted both at room and low (77 K) temperatures. Samples with 2000 appm of oxygen contain crystalline defects (trapping all oxygen) while those with 300 appm are completely glassy. Toughness results clearly indicate that these defects embrittle the glass. Therefore, careful attention must be paid during synthesis with respect to the oxygen content to get a completely glassy alloy. This issue is of paramount importance when dealing with mechanical properties such as toughness.