Triangle Criterion of Glass-Forming Ability and Stability for Metallic Glasses
Based on the glass-forming ability(GFA)during cooling process and the glass stability(GS)of heating process,a triangle to evaluate GFA and GS,namely Tri-FAS,with the combination of pseudo-four characteristic parameters as vertices was established.Accordingly,a GFA&GA criterion(G-FAS)was deduced as G-FAS=Tg/Tl+Tx/Tl+Tx/Tg(Tx is onset crystallization temperature;Tl is liquid temperature;Tg is glass transition temperature).Additionally,the criterion was modified based on the competitive relationship between amorphous phase and crystal phase during cooling process and the contribution of each component to the criterion:G-FASm=Tg/(1.5Tx)+Tx/T+Tx/Tg and G-FASm'=Tg/Tl+Tx/Tl+(Tx/Tg)a(a≈1.5±0.2).The correlation between G-FAS and critical cooling rate Rc and that between G-FAS and Txg(Txg reflects the supercooled liquid region of glass,Txg=Tx/Tg)were discussed,which could reflect GFA and GS,respectively.Through the determination results of GFA and GS of abundant metallic glasses and other glass formers,the validity of the proposed G-FAS criterion was evaluated.Results show that with respect to both GFA and GS,the G-FAS criterion is reliable in various glass former systems,showing wide applications.The proposed Tri-FAS and G-FAS criterion can provide guidance during the fabrication and application of metallic glasses.