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

作　　者：JIA Ran BIAN XiuFang WANG YingYing 

机构地区：[1]Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials of Ministry of Education, Shandong University, Jinan 250061,China

出　　处：《Chinese Science Bulletin》2011年第36期3912-3918,共7页

基　　金：supported by the National Basic Research Program of China (2007CB613901);the National Natural Science Foundation of China (50871062 and 50831003);the Natural Science Foundation of Shandong Province (Z2008F08)

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.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.

关 键 词：玻璃形成 洛杉矶 力学测定 液体 热力学函数 玻璃化转变温度 SLIQ 温度曲线 

分 类 号：TG139.8[一般工业技术—材料科学与工程]