Evaluating the correlation between liquid fragility and glass-forming ability in the extremely strong Ce-based bulk metallic glasses

Abstract

This investigation focuses on liquid fragility (m) and its correlation with glass-forming ability (GFA) of Ce-Ga-Cu, Ce-Al-Cu-Ni and newly developed Ce-Ga-Cu-Ni bulk metallic glass (BMG) systems. The present Ce-based BMGs belong to the extremely strong glass-forming system, whose fragility m values lie in a strong liquid range of 18–33. The quantitative correlation between m and GFA in the present Ce-based BMGs cannot be described well by previous criteria proposed by Senkov [Phys. Rev. B 76, 104202 (2007)], Wang [Appl. Phys. Lett. 100, 261913 (2012)], and Johnson [Nat. Commun. 7, 10313 (2016)]. By considering both the stability of the liquid phase and the stability of the competing crystalline phases, it is found that the stability of the competing crystalline phases plays a dominant role in the determination of GFA of strong Ce-based BMGs. And, the influence of reduced glass transition temperature (Trg) on GFA would be submerged by that of fragility m when m is below ∼30. The results help in further understanding the underlying correlation between fragility and GFA in metallic glasses, especially for the strong glass-forming liquids.