Composition screening of Zr-Cu-Al-Y bulk metallic glasses

Abstract

A new composition design method that combines the deep-eutectic rule and the driving-force criterion has been proposed and applied to the typical Zr-Cu-Al-Y bulk metallic glass system. By thermodynamic calculation and experimentation, the glass formation ranges at 2 at.% and 5 at.% Y were determined, and an amorphous rod of 8 mm in diameter was obtained in the Zr50Cu30Al15Y5 alloy with the aid of parameter criterions additionally. The results indicate that the glass-forming ability relates to the types of the competing crystalline phases during the glass formation. Unlike binary or ternary compounds, having the solid solution phase as the competing phase would deteriorate the glass-forming ability. Moreover, the driving-force is a necessary condition for the glass formation and has a threshold value for the glass formers. The findings in this work would provide an important guidance for the reliable and efficient composition design of novel bulk metallic glasses.