Superstoichiometric (Al,Cr)N: Nitrogen's whereabouts and role in structure-property relationships

Kód výsledku v 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>

Výsledek na webu

<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>

Jazyk výsledku

angličtina

Název v původním jazyce

Superstoichiometric (Al,Cr)N: Nitrogen's whereabouts and role in structure-property relationships

Popis výsledku v původním jazyce

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.

Název v anglickém jazyce

Superstoichiometric (Al,Cr)N: Nitrogen's whereabouts and role in structure-property relationships

Popis výsledku anglicky

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.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10300 - Physical sciences

Projekt

—

Návaznosti

S - Specificky vyzkum na vysokych skolach

Rok uplatnění

2025

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Acta Materialia

ISSN

1359-6454

e-ISSN

1873-2453

Svazek periodika

294

Číslo periodika v rámci svazku

August

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

13

Strana od-do

121158

Kód UT WoS článku

001504611000001

EID výsledku v databázi Scopus

2-s2.0-105005866265