Evaluation of liquid fragility and thermal stability of Al-based metallic glasses by equivalent structure parameter

Abstract

Based on extended Ideal-Atomic-Packing model, we propose an equivalent structure parameter “ 6 x + 11 y ” to evaluate fragility and thermal stability of Al–TM–RE metallic glasses, where x and y are composition concentrations of transition metal (TM) and rare earth (RE), respectively. Experimental results show that glass forming compositions with “ 6 x + 11 y ” near 100 have the smallest fragility parameter and best structure stability. In addition, “ 6 x + 11 y ” parameter has a positive relationship with onset-crystallization temperature, T x . Al–TM–RE glassy alloys with ( 6 x + 11 y ) ⩽ 100 undergo primary crystallization of fcc-Al nanocrystals, while alloys with ( 6 x + 11 y ) > 100 exhibit nanoglassy or glassy crystallization behavior.