Topological and kinetics considerations in the glass formation of AL-rich AL-Ni based alloys

Abstract

Our meticulous study of the glass forming ability (GFA) of the Al-rich Al-Ni alloy revealed the existence of a fully eutectic microstructure at a hypereutectic composition range, pointing to a skewed eutectic coupled zone, which coincided with the observation of possible glass formation at a Ni-enriched alloy This finding prompted us to give equal weight to both the high, and low Ni content compositions in our subsequent study of the GFA of Al-Ni based alloys containing Zr, Hf, Y and Ti. Indeed in each of the Al-rich Al-Ni-Zr, Al-Ni-Hf and Al-Ni-Y alloy systems, two optimal glass formers were located in a single eutectic. Kinetic considerations pointed to the composition at high solute contents where the addition of large sized atoms with strong chemical affinity were effective in suppressing eutectic growth. On the other hand, topological considerations directed to the lower solute content alloys where atomic arrangement most efficiently fill space.