Abstract The Au-based bulk metallic glass-forming alloy Au70Cu5.5Ag7.5Si17 is the first atomic system in which monotropic polymorphism has been experimentally found. In this study, strategies for measuring thermodynamic quantities such as heat capacity, transformation enthalpy and entropy, and Gibbs free energy for stable and metastable phases are evaluated based on this system. The transformation enthalpies between phases are determined via differential scanning calorimetry (DSC); the corresponding heat capacities are measured via stochastic temperature-modulated DSC (TOPEM); and the equilibrium melting temperatures of metastable phases, only detectable at high rates, are determined via fast DSC (FDSC). Whereas the slow heating rate of conventional DSC limits the characterization of metastable phases, the combination of both DSC and FDSC allows for their detailed heat-capacity determination. Furthermore, various approximation functions that have previously been used to determine the temperature dependence of the thermodynamic driving force for nucleation and crystallization are compared with the experimental data.

中文翻译：

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块状金属玻璃中多晶型的热力学：通过快速差示扫描量热法测量热容量

摘要 Au基块体金属玻璃形成合金Au70Cu5.5Ag7.5Si17是第一个通过实验发现单向性多晶现象的原子系统。在这项研究中，基于该系统评估了热力学量的测量策略，例如热容量、相变焓和熵以及稳定和亚稳态相的吉布斯自由能。相间的转化焓通过差示扫描量热法 (DSC) 确定；相应的热容是通过随机温度调制 DSC (TOPEM) 测量的；亚稳相的平衡熔化温度只能在高速率下检测，通过快速 DSC (FDSC) 确定。而传统 DSC 的缓慢加热速率限制了亚稳态相的表征，DSC 和 FDSC 的组合允许进行详细的热容量测定。此外，以前用于确定成核和结晶的热力学驱动力的温度依赖性的各种近似函数与实验数据进行了比较。