Al-Based Amorphous Alloys at the Limit of Glass Forming Ability

Abstract

New At based amorphous alloy compositions Al90Ni8Fe1Ce1, Al92Ni4Ce4,Al90Ni4Ce6, Al85Ni5Co2Y8 and Al85Ni5Co2Ce8 are reported at the edge ofglass forming ability (GFA). Some of them, with the highest possible Alcontent are two-phased materials (Al nanocrystals and a residualamorphous phase) already in the as-cast state. Nevertheless, theircrystallization characteristics resemble to those of fully amorphoussamples. The characteristics of crystallization were determined by DSCand DTA and the structural properties of the nano- and of thefully-crystallized states were studied by XRD and SEM. Besides theusual kinetic characteristics (Delta H, E-a, Avrami exponent, etc.) thelong term thermal stability was also studied using the DSC data and wascompared with that of other Al amorphous alloys reported in theliterature.