Thermodynamic properties and equation of state of fcc aluminum and bcc iron, derived from a lattice vibrational method
Thermodynamic properties and equation of state of fcc aluminum and bcc iron, derived from a lattice vibrational method
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DOI：
10.1007/s00269-010-0371-6
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发表时间：
2010-12-01
影响因子：
1.4
通讯作者：
Schmid-Fetzer, Rainer
中科院分区：
文献类型：
--
作者：
Jacobs, Michel H. G.;Schmid-Fetzer, Rainer
本文用晶格振动方法导出了纯铝和纯铁在压力-温度空间中的热物理和热化学性质。这种半经验技术是基于Mie-Gruneisen-Debye（MGD）方法或Kieffer模型的扩展，以结合声子谱的细节。它包括治疗的内在非谐性，电子效应的基础上的自由电子气模型，和磁效应的基础上的Calphad方法。我们表明，基恩的静态晶格的状态方程是更好地适合代表热力学数据铝从1巴到压力在多兆巴区域相对于维奈的通用和Birch-Murnaghan状态方程。看来MGD和Mie-Gruneisen-Kieffer方法产生类似的结果，但最后一个更好地代表低于室温的热容。对于铁，我们表明，热膨胀率的高温行为可以解释内的Calphad方法的压力依赖的居里温度与-1和0 K/GPa之间的斜率。
We use a lattice vibrational technique to derive thermophysical and thermochemical properties of the pure elements aluminum and iron in pressure-temperature space. This semi-empirical technique is based on either the Mie-Gruneisen-Debye (MGD) approach or an extension of Kieffer's model to incorporate details of the phonon spectrum. It includes treatment of intrinsic anharmonicity, electronic effects based on the free electron gas model, and magnetic effects based on the Calphad approach. We show that Keane's equation of state for the static lattice is better suitable to represent thermodynamic data for aluminum from 1 bar to pressures in the multi-megabar region relative to Vinet's universal and the Birch-Murnaghan equation of state. It appears that the MGD and Mie-Gruneisen-Kieffer approach produce similar results, but that the last one better represents heat capacity below room temperature. For iron we show that the high temperature behavior of thermal expansivity can be explained within the Calphad approach by a pressure-dependent Curie temperature with a slope between -1 and 0 K/GPa.