Zirconium purity influence on the critical diameter and thermal indicators of the Zr48Cu36Al9Ag7 alloy

Abstract

As it is known, the glass forming ability of Zr-based alloys is very sensitive to oxygen content. Oxygen contamination may come from raw zirconium and from alloy preparation stages as well. This work was focused on both factors. Using inert gas fusion method authors measured oxygen content in the zirconium delivered by five different providers as well as in five cone-shaped ingots after a full preparation process. Oxygen level influence on the critical diameter of Zr48Cu36Al9Ag7 alloy was quantitatively determined by cone test. Several common thermal indicators using characteristic temperatures were also calculated. They mostly exhibited high sensitivity to oxygen level as their correlation with the critical diameter was very high. Obtained results revealed that zirconium purity is not a relevant parameter in its quality description. The main GFA influencing factor is oxygen contamination level which should never be neglected. Moreover, an in-depth analysis including cost/quality aspects has been conducted in order to obtain practical guidelines for Zr-based bulk metallic glasses preparation.