Role of rare-earth elements in glass formation of Al–Ca–Ni amorphous alloys

► Effects of rare-earth elements on the glass forming-ability of Al-Ca-Ni system were investigated. ► The optimum doping content of all the four rare-earth elements was found to be 1%. ► Ytterbium is the most effective in improving the glass forming-ability of Al-Ca-Ni system. ► Atomic size difference between the rare-earth elements and Ca is the key factor in enhancing GFA. Effects of different rare-earth (RE) elements (i.e., Y, Ce, La and Yb) on the glass forming-ability (GFA) of Al–Ca–Ni alloy system were systematically investigated. The optimum addition content of all the four RE is 1 at.% and ytterbium is the most effective as far as the GFA is considered. Our analysis confirmed that proper additions of Yb could not only impede the formation of the competing α-Al clusters, but also enhance the liquid stability (i.e., lower the liquidus temperature). Although additions of Y, Ce and La in the Al 88Ca 7Ni 5 can also retard the α-Al precipitation, nevertheless, it seemed that their large atomic size difference with Ca could destabilize the original liquid stability (i.e., increase the liquidus temperature).