Quaternary Al-Cu-Mg-Si Q Phase: Sample Preparation, Heat Capacity Measurement and First-Principles Calculations
Quaternary Al-Cu-Mg-Si Q Phase: Sample Preparation, Heat Capacity Measurement and First-Principles Calculations
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DOI：
10.1007/s11669-015-0426-y
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发表时间：
2015-11
影响因子：
1.4
通讯作者：
A. Löffler;A. Zendegani;J. Gröbner;M. Hampl;R. Schmid-Fetzer;H. Engelhardt;M. Rettenmayr;F. Körmann;T. Hickel;J. Neugebauer
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文献类型：
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作者：
A. Löffler;A. Zendegani;J. Gröbner;M. Hampl;R. Schmid-Fetzer;H. Engelhardt;M. Rettenmayr;F. Körmann;T. Hickel;J. Neugebauer
第四季Q相是Al-Cu-Mg-Si合金体系中重要的析出相，其精确的热力学描述对于进一步定制轻质结构应用的材料类别至关重要。为了改进这一阶段的热化学参数集，我们采用了实验测量和第一性原理计算相结合的方法，重点关注热容。其精确的实验测定需要制备纯Q相样品和复杂的量热测量。在理论方面，需要同时处理准谐波近似中的晶格振动、电子激发和复合能量形式中的组态熵，以实现对热容的完整描述。评价结果表明，第一原理和Calphad模型具有较高的预测能力。
The quaternary Q phase is an important precipitate phase in the Al-Cu-Mg-Si alloy system and its accurate thermodynamic description is crucial for further tailoring this material class for light-weight structural applications. In order to achieve an improved thermochemical parameter set of this phase, we used a combination of experimental measurements and first-principles calculations, which was focussed on the heat capacity. Its accurate experimental determination required the preparation of pure samples of Q phase and sophisticated calorimetric measurements. On the theoretical side, a simultaneous treatment of lattice vibrations within the quasiharmonic approximation, electronic excitations, and configuration entropy within the compound energy formalism were required to achieve a complete description of the heat capacity. The evaluation demonstrates the high predictive power of the first-principles as well as the Calphad modeling.