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

Based on extended Ideal-Atomic-Packing model, we propose an equivalent structure parameter “6x+11y6x+11y” 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 “6x+11y6x+11y” near 100 have the smallest fragility parameter and best structure stability. In addition, “6x+11y6x+11y” parameter has a positive relationship with onset-crystallization temperature, TxTx. Al–TM–RE glassy alloys with (6x+11y)⩽100(6x+11y)⩽100 undergo primary crystallization of fcc-Al nanocrystals, while alloys with (6x+11y)>100(6x+11y)>100 exhibit nanoglassy or glassy crystallization behavior.