Composition rules from electron concentration and atomic size factors in Zr-Al-Cu-Ni bulk metallic glasses

In this paper, we will discuss and apply the formation rules for bulk metallic glasses, originated from quasicrystals composition rules, by combining two most common factors, atomic size factor and electron concentration (e/a) factor. According to literature survey, to our experience on quasicrystal formation, and to our own experimental verification, we propose two criteria, based on atomic size and electron concentration e/a respectively. The first criterion is quantified as the R_av-constant criterion, R_av being the average atomic radius, and the second one the e/a-constant criterion. In a given alloy system the optimum BMGs and their crystalline counter parts tend to share the same R_av and e/a values. These criteria have been applied to determine the ideal BMGs in Zr-Al-Cu-Ni system.