Superstoichiometric (Al,Cr)N: Nitrogen's whereabouts and role in structure-property relationships
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216224%3A14310%2F25%3A00141223" target="_blank" >RIV/00216224:14310/25:00141223 - isvavai.cz</a>
Result on the web
<a href="https://doi.org/10.1016/j.actamat.2025.121158" target="_blank" >https://doi.org/10.1016/j.actamat.2025.121158</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1016/j.actamat.2025.121158" target="_blank" >10.1016/j.actamat.2025.121158</a>
Alternative languages
Result language
angličtina
Original language name
Superstoichiometric (Al,Cr)N: Nitrogen's whereabouts and role in structure-property relationships
Original language description
The role of light elements in ceramic materials cannot be overestimated. By tuning their concentration, a whole multitude of mechanisms can be activated, directly influencing the material's functional properties. However, accurate determination of light element concentrations remains a challenge and is often, especially in superstoichiometric compounds, overlooked. Here, we provide atomic-scale insight into nitrogen incorporation in superstoichiometric (Al,Cr)Nx coatings (x = 1.01–1.11) with similar Al/(Al+Cr) ratios (0.59–0.63) by combining elemental concentrations, stress-free lattice parameters, and ab initio calculations. Below a threshold of x ≈ 1.06–1.08, excess nitrogen predominantly occupies interstitial lattice sites, while beyond this point, it can also incorporate into vacant metal sites (anti-sites). We then conducted a detailed investigation on two superstoichiometric coatings: (Al,Cr)N1.08, with nitrogen near the threshold, and (Al,Cr)N1.11, which exceeds it. While (Al,Cr)N1.08 features densely packed, elongated fibrous grains with a strong (111) growth orientation, (Al,Cr)N1.11 develops a fine-grained microstructure with a (220) growth orientation. These structural changes significantly affect mechanical properties: (Al,Cr)N1.08 is 9 % harder (34.4 GPa vs. 31.6 GPa) with superior abrasive resistance, while (Al,Cr)N1.11 has 9 % higher fracture toughness (4.15 MPa√m vs. 3.80 MPa√m) and enhanced microcracking and crack-branching behaviour. Our findings not only demonstrate the tunability of mechanical properties in superstoichiometric (Al,Cr)Nx coatings but also highlight the broader potential of superstoichiometric nitrides and ceramics for advanced applications.
Czech name
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Czech description
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Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10300 - Physical sciences
Result continuities
Project
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Continuities
S - Specificky vyzkum na vysokych skolach
Others
Publication year
2025
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Acta Materialia
ISSN
1359-6454
e-ISSN
1873-2453
Volume of the periodical
294
Issue of the periodical within the volume
August
Country of publishing house
GB - UNITED KINGDOM
Number of pages
13
Pages from-to
121158
UT code for WoS article
001504611000001
EID of the result in the Scopus database
2-s2.0-105005866265