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Published November 8, 2016 | Published + Supplemental Material
Journal Article Open

Lattice Vibrations Change the Solid Solubility of an Alloy at High Temperatures

Abstract

We develop a method to accurately and efficiently determine the vibrational free energy as a function of temperature and volume for substitutional alloys from first principles. Taking Ti_(1−x)Al_xN alloy as a model system, we calculate the isostructural phase diagram by finding the global minimum of the free energy corresponding to the true equilibrium state of the system. We demonstrate that the vibrational contribution including anharmonicity and temperature dependence of the mixing enthalpy have a decisive impact on the calculated phase diagram of a Ti_(1−x)Al_xN alloy, lowering the maximum temperature for the miscibility gap from 6560 to 2860 K. Our local chemical composition measurements on thermally aged Ti_(0.5)Al_(0.5)N alloys agree with the calculated phase diagram.

Additional Information

© 2016 American Physical Society. Received 10 March 2015; revised manuscript received 7 August 2015; published 8 November 2016. This work was supported by the Swedish Foundation for Strategic Research Programs (Stiftelsen för Strategisk Forskning) No. SRL10-0026 and No. RMA08-0069, and FUNCASE, the Swedish Research Council (Vetenskapsrådet) Projects No. 2012-4401, No. 621-2011-4426, and No. 2015-04391, the Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linköping University (Faculty Grant SFO-Mat-LiU No. 2009 00971), the Swedish Governmental Agency for Innovation Systems (Vinnova) through the M-ERA.net project MC_2 and SECO Tools AB. Support from the Swedish Research Council (Vetenskapsrådet) Program No. 637-2013-7296 is gratefully acknowledged by O. H. B. A. acknowledges financial support from the Swedish Research Council (Vetenskapsrådet) through Grants No. 621-2011-4417 and No. 330-2014-6336 and by Marie Sklodowska Curie Actions, Cofund, Project INCA 600398. N. S. and J. B. acknowledge the financial support from the Erasmus Mundus Joint European Doctoral Programme DocMASE. I. A. A. acknowledges the support from the Grant of Ministry of Education and Science of the Russian Federation in the framework of Increase Competitiveness Program of NUST "MISIS" (No. K2-2016-013). We thank Isabella Schramm (Saarland University) for the assistance with atom probe tomography measurements. All calculations were performed using the supercomputer resources of the Swedish National Infrastructure for Computing, National Supercomputer Centre at Linköing University, and the PDC Center for High Performance Computing at the KTH Royal Institute of Technology. The Atom Probe was financed by the Deutsche Forschungsgemeinschaft and the Federal State Government of Saarland (INST 256/298-1 FUGG).

Attached Files

Published - PhysRevLett.117.205502.pdf

Supplemental Material - sm.pdf

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Created:
August 18, 2023
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October 23, 2023