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Published January 2014 | public
Journal Article

Lambda transitions in materials science: Recent advances in CALPHAD and first-principles modelling

Abstract

This paper provides a comprehensive overview of state-of-the-art computational techniques to thermodynamically model magnetic and chemical order–disorder transitions. Recent advances as well as limitations of various approaches to these so-called lambda transitions are examined in detail, focussing on calphad models and first-principles methods based on density functional theory (DFT). On the one hand empirical implementations –based on the Inden–Hillert–Jarl formalism –are investigated, including a detailed interpretation of the relevant parameters, physical limiting cases and potential extensions. In addition, Bragg–Williams-based approaches as well as cluster-variation methods of chemical order–disorder transitions are discussed. On the other hand, it is shown how magnetic contributions can be introduced based on various microscopic model Hamiltonians (Hubbard model, Heisenberg model and beyond) in combination with DFT-computed parameters. As a result of the investigation we were able to indicate similarities between the treatment of chemical and magnetic degrees of freedom as well as the treatment within the calphad and DFT approaches. Potential synergy effects resulting from this overlap have been derived and alternative approaches have been suggested, in order to improve future thermodynamic modelling of lambda transitions.

Additional Information

© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. Received 16 August 2013, revised 5 November 2013, accepted 8 November 2013; Published online 20 December 2013. One of us (GG) acknowledges support from the US Department of Energy (DOE), Office of Fossil Energy, under Grant No. DE-FG00568, with Richard Dunst as the program manager. Work at CCFE was funded by the RCUK Energy Programme under grant EP/I501045 and the EuropeanCommunities under the Contract of Association between EURATOM and CCFE. The views and opinions expressed herein do not necessarily reflect those of the European Commission. Funding by the collaborative research center SFB 761 'Stahl – ab initio' of the Deutsche Forschungsgemeinschaft and the Interdisciplinary Centre for Advanced Materials Simulation (ICAMS), which is supported by ThyssenKruppAG, Bayer MaterialScienceAG, Salzgitter Mannesmann Forschung GmbH, Robert Bosch GmbH, Benteler Stahl/Rohr GmbH, Bayer Technology Services GmbH and the state of North-Rhine Westphalia as well as the European Commission in the framework of the European Regional Development Fund (ERDF), is gratefully acknowledged. Discussions with Igor A. Abrikosov, Gerhard Inden, Marcel H.F. Sluiter and Wei Xiong are gratefully acknowledged.

Additional details

Created:
August 22, 2023
Modified:
October 26, 2023