A criterion of glass-forming ability and stability derived from pseudo-four characteristic temperatures

Abstract

A quadrilateral with pseudo-four characteristic temperatures as vertices is established based on four aspects (1. The onset crystallization temperature Tx: resistance to crystallization; 2. The liquid temperature Tl: liquid stability; 3. The supercooled liquid region of glass (SLRglass) ΔTx = Tx-Tg, where Tg is the glass transition temperature: stability of SLRglass; 4. The supercooled liquid region of melt (SLRmelt) ΔTg = Tl-Tg: glass-forming ability/tendency of glass itself) from two perspectives of the glass-forming ability (GFA) in cooling process and glass stability (GS) in heating process. According to pseudo-four characteristic temperatures, a glass-forming ability and stability criterion (G-FAS criterion) is derived and modified: G-FAS = Tx/Tl+(Tx-Tg)/(Tl-Tg) and G-FASm = Tx/Tl+(Tx-Tg)/(1.5Tx-Tg). The validity and feasibility of the newly proposed criterion are elaborated and discussed through evaluating the correlation between criterion and Rc and the consistency with the boundary conditions. Comparison with other currently existing 23 characteristic temperature-based criteria shows that the presently proposed criterion has excellent performance both correlation with Rc and consistency with boundary conditions.