Crystallization behavior of the Al86Ni8Y6 metallic glass forming alloy upon rapid cooling

Abstract

In this study, the crystallization behavior of Al86Ni8Y6 upon rapid cooling from the equilibrium melt is investigated and the crystalline phases that compete with the glass formation are identified. Al86Ni8Y6 is one of the best glass formers in the ternary Al-Ni-Y system. Contrary to previous studies suggesting α-Al as the primary phase upon quenching, this study reveals that glass formation is strongly restricted by the formation of the primary precipitating ternary intermetallic compound Al23Ni6Y4. The nucleation of Al23Ni6Y4 appears to be triggered by yttrium oxide particles present in the melt acting as heterogeneous nucleation sites. Once the primary phase Al23Ni6Y4 has been formed, further crystallization of the Ni and Y depleted melt occurs as α-Al. The corresponding results are shown and discussed with respect to their effects on the glass formation.