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Quantum-mechanical study of tensorial elastic and high-temperature thermodynamic properties of grain boundary states in superalloy-phase Ni3Al
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SYSNO ASEP 0478808 Document Type C - Proceedings Paper (int. conf.) R&D Document Type Conference Paper Title Quantum-mechanical study of tensorial elastic and high-temperature thermodynamic properties of grain boundary states in superalloy-phase Ni3Al Author(s) Friák, Martin (UFM-A) RID, ORCID
Všianská, Monika (UFM-A)
Holec, D. (AT)
Šob, Mojmír (UFM-A) RID, ORCIDNumber of authors 4 Article number UNSP 012019 Source Title 38TH RISO INTERNATIONAL SYMPOSIUM ON MATERIALS SCIENCE. - Bristol : IOP PUBLISHING LTD, 2017 - ISSN 1757-8981 Number of pages 11 s. Publication form Online - E Action Riso International Symposium on Materials Science /38./ Event date 04.09.2017 - 08.09.2017 VEvent location Denmark Country DE - Germany Event type WRD Language eng - English Country GB - United Kingdom Keywords Anisotropic elastic properties ; Defects in solids ; Elastic tensors Subject RIV BM - Solid Matter Physics ; Magnetism OECD category Condensed matter physics (including formerly solid state physics, supercond.) R&D Projects GA16-24711S GA ČR - Czech Science Foundation (CSF) LQ1601 GA MŠMT - Ministry of Education, Youth and Sports (MEYS) LM2015069 GA MŠMT - Ministry of Education, Youth and Sports (MEYS) Institutional support UFM-A - RVO:68081723 UT WOS 000409355600019 EID SCOPUS 85028354722 DOI 10.1088/1757-899X/219/1/012019 Annotation Grain boundaries (GBs), the most important defects in solids and their properties are crucial for many materials properties including (in-)stability. Quantum-mechanical methods can reliably compute properties of GBs and we use them to analyze (tensorial) anisotropic elastic properties of interface states associated with GBs in one of the most important intermetallic compounds for industrial applications, Ni3Al. Selecting the Sigma 5(210) GBs as a case study because of its significant extra volume, we address the mechanical stability of the GB interface states by checking elasticity-based Born stability criteria. One critically important elastic constant, C 55, is found nearly three times smaller at the GB compared with the bulk, contributing thus to the reduction of the mechanical stability of Ni3Al polycrystals. Next, comparing properties of Sigma 5(210) GB state which is fully relaxed with those of a Sigma 5(210) GB state when the supercell dimensions are kept equal to those in the bulk we conclude that lateral relaxations have only marginal impact on the studied properties. Having the complete elastic tensor of Sigma 5(210) GB states we combine Green's-function based homogenization techniques and an approximative approach to the Debye model to compare thermodynamic properties of a perfect Ni3Al bulk and the Sigma 5(210) GB states. In particular, significant reduction of the melting temperature (to 79-81% of the bulk value) is predicted for nanometer-size grains. Workplace Institute of Physics of Materials Contact Yvonna Šrámková, sramkova@ipm.cz, Tel.: 532 290 485 Year of Publishing 2018
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