Thermodynamic determination of fragility in La-based glass-forming liquid

• 来源期刊: 科学通报(英文版)
• 学科: 工学
• 年，卷（期）: 2011,（36）
• 页码范围: 3912-3918
• 页数: 7页
• 分类号: TG139.8
• 语种: 中文

摘要

Differences in the thermodynamic functions between the liquid and crystalline states of La-based bulk metallic glasses alloys were calculated with the specific heat capacity Cp and the fusion heat ΔHf,which we measured. Fragility indexes having different thermodynamic definitions were calculated from the temperature dependence of excess entropy ΔSliq-cry. It is ambiguous for La-based glass-forming liquid to evaluate fragility from the intercepts of ΔSliq-cry-temperature curves. We found that the thermodynamic fragility MΔS,denoted ΔS,decreases at the onset melting temperatures Tm rather than at glass transition temperatures Tg,and relates linearly with the kinetic fragility m. The correlations between thermodynamic fragility and kinetic fragility are discussed within the frameworks of the Adam-Gibbs relationship and potential energy landscape theory.