Selection of new glass-forming compositions in Al–La system using a combination of topological instability and thermodynamic criteria

A combination of an extension of the topological instability “λ criterion” and a thermodynamic criterion were applied to the Al–La system, indicating the best range of compositions for glass formation. Alloy compositions in this range were prepared by melt-spinning and casting in an arc-melting furnace with a wedge-section copper mold. The GFA of these samples was evaluated by X-ray diffraction, differential scanning calorimetry and scanning electron microscopy. The results indicated that the γ* parameter of compositions with high GFA is higher, corresponding to a range in which the λ parameter is greater than 0.1, which are compositions far from Al solid solution. A new alloy was identified with the best GFA reported so far for this system, showing a maximum thickness of 286 μm in a wedge-section copper mold.