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A physically consistent method to implement volume properties in Calphad-type thermodynamic descriptions of alloys

一种在合金的 Calphad 型热力学描述中实现体积特性的物理一致方法

基本信息

批准号：
163415057
负责人：
Dr. Michael H.G. Jacobs
金额：
--
依托单位：
Institut für Metallurgie
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2010
资助国家：
德国
起止时间：
2009-12-31 至 2016-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/163415057?language=en
关键词：
physically consistent method implement volume

项目摘要

The impact of volume changes in alloys is of utmost importance in optimizing performance and density of materials, the development of joints and in the study of materials behavior during processing when phase transformations occur, such as casting and heat treatment. The development of a new method is proposed to generalize the Calphad approach in such a way that physically consistent thermodynamic databases can be constructed with the non-trivial characteristic that volume properties are derived from them. A correct self-consistent thermodynamic description of volume related properties, such as thermal expansivity and compressibility, along with the pressure dependence of thermodynamic functions, benefits after the successful completion of this project.So far serious attempts to develop a thermodynamic database including the derivation of volume properties have been limited to the fields of mineral physics and geophysics. In these fields the accent in the thermodynamic modelling for the development of databases of silicate and oxide systems shifts to vibrational models coupled with ab initio methods to prevent unrealistic behavior in thermodynamic properties and to achieve better predictions of properties at conditions where experimental data are missing. Although it has been shown that these methods are quite successful to develop thermodynamic databases, it is impracticable at this stage of research to remake thermodynamic databases, which are coupled to Gibbs energy formulations based on the Calphad approach. It is the goal of the proposed research to develop a Gibbs energy formalism from which all thermodynamic properties, including the volume related properties, can be derived. This formalism serves as an interim solution that can be accommodated in Calphad-type modelling. The development of this formalism is assisted by vibrational formalisms and ab initio methods to assure that physically unrealistic behavior in thermodynamic properties is prevented. Additionally they are used to predict properties for which presently no experimental data are available. They will also be used to gain more insight in the effect of composition on vibrational and static lattice properties to obtain a partitioning of physical effects into the excess properties. To enhance the application of the proposed method, a thermodynamic dataset including volume properties is developed for selected binary and ternary systems in the system Ag-Au-Cu-Ni-Pd-Pt. Vibrational formalisms are employed to achieve a physically self-consistent description of phases in this system. This description consists of a dataset containing vibrational input parameters, analogous to those developed in mineral physics and geophysics. These parameters could be used in these fields for future studies of materials at the extreme conditions prevailing in the solid mantle and core of the earth. The better constrained thermodynamic properties serve as constraints in the interim solution, which can be accommodated in present day Calphad-type modelling. That results in a dataset generally applicable in the Calphad approach to derive thermodynamic properties in pressure-temperature-composition space. Because the developed Gibbs energy formalism is self-consistent and independent of the chosen system it is additionally applicable in a general way to make predictions of these properties in the low pressure regime, which are important for applications in industrial processes.

合金中体积变化的影响在优化材料的性能和密度、接头的开发以及在相变发生时的加工过程中（例如铸造和热处理）材料行为的研究中至关重要。提出了一种新的方法的发展，以推广的Calphad方法，在这样一种方式，物理上一致的热力学数据库可以构建与非平凡的特性，体积属性来自他们。该项目的成功完成将有助于建立一个正确的、自洽的、与体积相关的热力学描述，如热膨胀系数和压缩系数，沿着热力学函数的压力依赖性。迄今为止，建立包括体积性质推导在内的热力学数据库的努力仅限于矿物物理和矿物物理领域。在这些领域的口音的硅酸盐和氧化物系统的数据库的发展的热力学建模转移到振动模型加上从头算方法，以防止不切实际的行为在热力学性质，并实现更好的预测性能的条件下，实验数据丢失。虽然它已被证明，这些方法是相当成功的开发热力学数据库，这是不切实际的，在这个阶段的研究，以改造热力学数据库，这是耦合到吉布斯能量公式的基础上的Calphad方法。这是拟议的研究的目标，以开发一个吉布斯能量形式主义，从所有的热力学性质，包括体积相关的属性，可以得出。这种形式主义作为一个临时的解决方案，可以容纳在Calphad型建模。这种形式主义的发展是协助振动形式主义和从头算方法，以确保物理上不切实际的行为，在热力学性质是防止。此外，它们还用于预测目前没有实验数据的性质。它们也将被用来获得更多的洞察力，在振动和静态晶格性质的组成的影响，以获得一个分区的物理效应到多余的属性。为了提高所提出的方法的应用，包括体积性质的热力学数据集的开发选定的二元和三元系统Ag-Au-Cu-Ni-Pd-Pt。振动形式主义，以实现物理自洽的描述相在这个系统中。该描述由包含振动输入参数的数据集组成，类似于矿物物理学和地球物理学中开发的参数。这些参数可用于这些领域的材料在极端条件下普遍存在于固体地幔和地球核心的未来研究。更好的约束的热力学性质作为约束的临时解决方案，这可以容纳在当今的Calphad型建模。这导致数据集通常适用于Calphad方法，以获得压力-温度-组成空间中的热力学性质。由于开发的吉布斯能量形式主义是自洽的，独立于所选择的系统，它是另外适用的，在一般的方式，使这些属性的预测在低压区，这是重要的工业过程中的应用。

项目成果

期刊论文数量（5）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Thermal equation of state of synthetic orthoferrosilite at lunar pressures and temperatures

月球压力和温度下合成正铁硅石的状态热方程

DOI：
10.1007/s00269-013-0605-5
发表时间：
2013
期刊：
Physics and Chemistry of Minerals
影响因子：
1.4
作者：
J. de Vries;M.H.G. Jacobs;A.P. van den Berg;M. Wehber;C. Lathe;C.A. McCammon;W. Van Westrenen
通讯作者：
W. Van Westrenen

Phase diagrams, thermodynamic properties and sound velocities derived from a multiple Einstein method using vibrational densities of states: an application to MgO–SiO2