Effect of high-temperature up-quenching on stabilizing off-eutectic metallic glasses

Abstract

Fast-heating calorimetry is used to study in operando the vitrification mechanism of off-eutectic ${\mathrm{Yb}}_{47}{\mathrm{Mg}}_{{}_{31}}{\mathrm{Zn}}_{19}{\mathrm{Cu}}_{3}$ liquid at a cooling rate of $10\phantom{\rule{0.16em}{0ex}}000\phantom{\rule{0.16em}{0ex}}\mathrm{K}\phantom{\rule{0.16em}{0ex}}{\mathrm{s}}^{--1}$. The glass forms only when it is quenched from between the melting and liquidus temperature, contradicting the need for full remelting. Zinc-rich precipitates, forming on quenching from above the liquidus, deteriorate vitrification---which also offers an alternative explanation to what has often been considered as liquid-liquid transition. Application of an up-quenching thermal protocol facilitates the glass formation by removing the precipitates in situ; it is generally applicable and may extend the glass-forming range of other off-eutectic glasses. This research demonstrates a strategy to develop bulk metallic glasses.