玻璃形成能力及稳定性三角形判定准则

Triangle Criterion of Glass-Forming Ability and Stability for Metallic Glasses

摘要:

根据降温过程的玻璃形成能力（GFA）和升温过程的玻璃稳定性（GS），构建了以伪四特征参数组合为顶点的判定玻璃形成能力和稳定性的三角形（Tri-FAS），从而推导出判定GFA&GS的准则：G-FAS=T_g/T_l+T_x/T_l+T_x/T_g（T_x为起始结晶温度；T_l为液体温度；T_g为玻璃化转变温度），并从降温过程非晶化与晶化之间的竞争关系和准则各组成项对准则的均衡贡献两个方面进行了修订：G-FAS_m=T_g/(1.5T_x)+T_x/T_l+T_x/T_g和G-FAS_m′=T_g/T_l+T_x/T_l+(T_x/T_g)^a (a≈1.5±0.2)。讨论了G-FAS与临界冷却速率R_c、G-FAS与T_xg（T_xg反映了玻璃的过冷液区，T_xg=T_x/T_g）的相关性，分别能够反映GFA和GS。通过大量金属玻璃和其他玻璃形成体从GFA和GS两方面对判定准则的有效性进行了评估，结果显示：该判定准则无论是GFA方面还是GS方面，在不同玻璃形成体系中均可靠有效，具有广泛应用性。提出的Tri-FAS和G-FAS判定准则在玻璃的生产和实际应用过程中具有指导作用。

Abstract:

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=T_g/T_l+T_x/T_l+T_x/T_g (T_x is onset crystallization temperature; T_l is liquid temperature; T_g 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-FAS_m=T_g/(1.5T_x)+T_x/T_l+T_x/T_g and G-FAS_m′=T_g/T_l+T_x/T_l+(T_x/T_g)^a (a≈1.5±0.2). The correlation between G-FAS and critical cooling rate R_c and that between G-FAS and T_xg (T_xg reflects the supercooled liquid region of glass, T_xg=T_x/T_g) 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.