Glass Formability in Al-based Multinary Alloys

The unique glass formation ability (GFA) of aluminum-based glasses is exhibited in that they do not follow the empirical rules developed for other metallic glass forming systems. The focus of this paper is an evaluation of the relationship between the GFA and some GFA related parameters in a ternary Al(100-x-y)Ni(x)Gd(y) (at. pct) series, where x (and y ) = 5-11 and x + y = 12-18. It was found that the alloys in the composition area near Al87Ni7Gd6 can amorphize most easily, while those alloys with decreased Al content exhibit positive changes in the GFA related parameters, including a higher thermal stability of amorphous alloys, a higher reduced glass transition temperature, and a higher viscosity of the alloy melt, implying that these alloys should exhibit a better GFA. Based on DTA measurements, the increased solidification temperature range, defined as the temperature difference between the initial and final melting reactions, was suggested to be responsible for the decreased GFA of alloys with decreased Al content. (Author)