Stability and elasticity of metastable solid solutions and superlattices in the MoN-TaN system: First-principles calculations

Koutná, N.; Holec, D.; Friák, Martin; Mayrhofer, P. H.; Šob, Mojmír

doi:https://dx.doi.org/10.1016/j.matdes.2018.02.033

Number of the records: 1

Stability and elasticity of metastable solid solutions and superlattices in the MoN-TaN system: First-principles calculations

1.

SYSNO ASEP	0493529
Document Type	J - Journal Article
R&D Document Type	Journal Article
Subsidiary J	Článek ve WOS
Title	Stability and elasticity of metastable solid solutions and superlattices in the MoN-TaN system: First-principles calculations
Author(s)	Koutná, N. (CZ) Holec, D. (AT) Friák, Martin (UFM-A)_{RID, ORCID} Mayrhofer, P. H. (AT) Šob, Mojmír (UFM-A)_{RID, ORCID}
Number of authors	5
Source Title	Materials and Design. - : Elsevier - ISSN 0264-1275 Roč. 144, APR (2018), s. 310-322
Number of pages	13 s.
Language	eng - English
Country	GB - United Kingdom
Keywords	nitride thin-films ; ti-al-n ; mechanical-properties ; molybdenum nitride ; electronic-properties ; oxidation resistance ; superhard materials ; optical-properties ; thermal-stability ; mixed-crystals ; MoN-TaN ; Phase stability ; Symmetry ; Elasticity ; Electronic properties
Subject RIV	BM - Solid Matter Physics ; Magnetism
OECD category	Condensed matter physics (including formerly solid state physics, supercond.)
R&D Projects	LQ1601 GA MŠMT - Ministry of Education, Youth and Sports (MEYS)
	GA16-24711S GA ČR - Czech Science Foundation (CSF)
Institutional support	UFM-A - RVO:68081723
UT WOS	000427609400029
EID SCOPUS	85042302061
DOI	10.1016/j.matdes.2018.02.033
Annotation	In order to develop design rules for novel nitride-based coatings, we investigate trends in thermodynamic, structural, elastic, and electronic properties ofMo1-xTaxNsingle-phase alloys together with (MoN)(1-x)/(TaN)(x) superlattices. Our calculations predict that hexagonal Mo1-xTaxN are the overall most stable ones, followed by the disordered cubic solid solutions and superlattices. The disordered cubic systems are energetically clearly favoured over their ordered counterparts. To explain this unexpected phenomenon, we perform an in-depth structural analysis of bond-lengths and angles, revealing that the disordered phase is structurally between the NaCl-type and the hexagonal NiAs-type modifications. Similarly, the bi-axial coherency stresses in MoN/TaN break the cubic symmetry beyond simple tetragonal distortions, leading to a new tetragonal zeta-phase (P4/nmm, #129). Both zeta-MoN and zeta-TaN have lower formation energy than their cubic counterparts. Unlike the cubic TaN, the zeta-TaN is also dynamically stable. The hexagonal alloys are predicted to be extremely hard, though, much less ductile than the cubic polymorphs and superlattices. (C) 2018 Elsevier Ltd. All rights reserved.
Workplace	Institute of Physics of Materials
Contact	Yvonna Šrámková, sramkova@ipm.cz, Tel.: 532 290 485
Year of Publishing	2019

Number of the records: 1