Change search
ReferencesLink to record
Permanent link

Direct link
An improved magnetic model for thermodynamic modeling
KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Computational Thermodynamics.
Thermocalc Software AB.
KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Technology.ORCID iD: 0000-0002-9920-5393
KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Computational Thermodynamics.ORCID iD: 0000-0001-5031-919X
2012 (English)In: Calphad, ISSN 0364-5916, E-ISSN 1873-2984, Vol. 39, 11-20 p.Article in journal (Refereed) Published
Abstract [en]

The standard magnetic model in the current CALPHAD modeling is based on the Inden-Hillert-Jarl model and an empirical constraint due to Weiss and Tauer that can be used to connect ferromagnetism and antiferromagnetism. In this work, we demonstrate that many artifacts can be produced by using the current approach when modeling systems with elements of different forms of magnetism. We then propose several simple measures to improve the standard magnetic model so that a physically and numerically correct and more accurate description for the Gibbs energy of magnetic ordering can be obtained in normal situations. Especially, we have assumed that each magnetic phase always possesses both ferromagnetic and antiferromagnetic states, with one of them stable and the other non-stable. The concept of 'effective magnetic moment' has also been introduced as a measure of the maximum magnetic entropy. A case study on the Al-Cr-Fe system has been performed at 0 K showing the importance of reasonable description of the magnetic phase diagrams. It has been stressed that the extended magnetic model in this work can be further employed for bridging atomistic and phenomenological modeling for multi-scale simulation.

Place, publisher, year, edition, pages
2012. Vol. 39, 11-20 p.
Keyword [en]
Magnetic ordering, Phase diagram, Ab initio, Fe-Ni, Fe-Rh, Al-Cr-Fe
National Category
Materials Engineering
URN: urn:nbn:se:kth:diva-96784DOI: 10.1016/j.calphad.2012.07.002ISI: 000311926800002ScopusID: 2-s2.0-84865427906OAI: diva2:532668

QC 20130109. Updated from manuscript to article in journal.

Available from: 2012-06-12 Created: 2012-06-12 Last updated: 2013-01-09Bibliographically approved
In thesis
1. Thermodynamic and Kinetic Investigation of the Fe-Cr-Ni System Driven by Engineering Applications
Open this publication in new window or tab >>Thermodynamic and Kinetic Investigation of the Fe-Cr-Ni System Driven by Engineering Applications
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This work is a thermodynamic and kinetic study of the Fe-Cr-Ni system as the core of stainless steels. The Fe-Cr, Fe-Ni and Cr-Ni systems were studied intensively using both computational and experimental techniques, including CALPHAD (CALculation of PHAse Diagrams), phase field simulation, ab initio modeling, calorimetry, and atom probe tomography. The purpose of this thesis is to reveal the complexity of the phase transformations in the Fe-Cr-Ni system via the integrated techniques. Due to the importance of the binary Fe-Cr system, it was fully reassessed using the CALPHAD technique by incorporating an updated description of the lattice stability for Fe down to zero kelvin. The improved thermodynamic description was later adopted in a phase field simulation for studying the spinodal decomposition in a series of Fe-Cr binary alloys. Using atom probe tomography and phase field simulation, a new approach to analyze the composition amplitude of the spinodal decomposition was proposed by constructing an amplitude density spectrum. The magnetic phase diagram of the Fe-Ni system was reconstructed according to the results from both ab initio calculations and reported experiments. Based on the Inden-Hillert-Jarl magnetic model, the thermodynamic reassessment of the Fe-Ni system demonstrated the importance of magnetism in thermodynamic and kinetic investigations. Following this, the current magnetic model adopted in the CALPHAD community was further improved. Case studies were performed showing the advantages of the improved magnetic model. Additionally, the phase equilibria of the Fe-Cr-Ni ternary were discussed briefly showing the need of thermodynamic and kinetic studies at low temperatures. The “low temperature CALPHAD” concept was proposed and elucidated in this work showing the importance of low temperature thermodynamics and kinetics for designing the new generation of stainless steels.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2012. v, 63 p.
phase transformation, magnetism, spinodal decomposition, stainless steel, low temperature CALPHAD, phase field, ab initio, atom probe tomography, calorimetry
National Category
Metallurgy and Metallic Materials
Research subject
SRA - E-Science (SeRC); SRA - Energy
urn:nbn:se:kth:diva-96707 (URN)978-91-7501-394-7 (ISBN)
Public defence
2012-08-28, sal B2, Brinellvägen 23, MSE, KTH, Stockholm, 10:00 (English)
StandUpSwedish e‐Science Research Center

QC 20120612

Available from: 2012-06-12 Created: 2012-06-10 Last updated: 2013-04-18Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textScopus

Search in DiVA

By author/editor
Xiong, WeiChen, QingPavel, KorzhavyiSelleby, Malin
By organisation
Computational ThermodynamicsMaterials Technology
In the same journal
Materials Engineering

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 118 hits
ReferencesLink to record
Permanent link

Direct link