Anomalous mechanical strengths and shear deformation paths of Al2O3 polymorphs with high ionicity

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F16%3A10364387" target="_blank" >RIV/00216208:11320/16:10364387 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/61989100:27740/16:10237916

Výsledek na webu

<a href="http://dx.doi.org/10.1039/c5ra25796d" target="_blank" >http://dx.doi.org/10.1039/c5ra25796d</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1039/c5ra25796d" target="_blank" >10.1039/c5ra25796d</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Anomalous mechanical strengths and shear deformation paths of Al2O3 polymorphs with high ionicity

Popis výsledku v původním jazyce

Alumina (Al2O3) formed by selective oxidization provides an effective way to protect aluminide alloys against corrosion for sustainable applications. Despite a broad interest and investigations on Al2O3 polymorphs such as alpha-Al2O3 and theta-Al2O3, their intrinsic mechanical strengths and atomic deformation mechanisms are not yet fully understood. In this research, density functional theory is used to show that the calculated shear moduli and mechanical strengths of theta-Al2O3 are substantially lower than those of alpha-Al2O3, and this explains why theta-Al2O3 is much weaker than alpha-Al2O3. An analysis of shear deformation paths and electronic structure indicates that the longest Al-O ionic bonds are responsible for the lattice instability of both polymorphs during shear, showing they have different anisotropic features. This study gives a novel view on the failure of thermally grown alpha-Al2O3 and theta-Al2O3, and it should help to improve the performance of thermal barrier coatings.

Název v anglickém jazyce

Anomalous mechanical strengths and shear deformation paths of Al2O3 polymorphs with high ionicity

Popis výsledku anglicky

Alumina (Al2O3) formed by selective oxidization provides an effective way to protect aluminide alloys against corrosion for sustainable applications. Despite a broad interest and investigations on Al2O3 polymorphs such as alpha-Al2O3 and theta-Al2O3, their intrinsic mechanical strengths and atomic deformation mechanisms are not yet fully understood. In this research, density functional theory is used to show that the calculated shear moduli and mechanical strengths of theta-Al2O3 are substantially lower than those of alpha-Al2O3, and this explains why theta-Al2O3 is much weaker than alpha-Al2O3. An analysis of shear deformation paths and electronic structure indicates that the longest Al-O ionic bonds are responsible for the lattice instability of both polymorphs during shear, showing they have different anisotropic features. This study gives a novel view on the failure of thermally grown alpha-Al2O3 and theta-Al2O3, and it should help to improve the performance of thermal barrier coatings.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10302 - Condensed matter physics (including formerly solid state physics, supercond.)

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2016

Kód důvěrnosti údajů

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

Název periodika

RSC Advances

ISSN

2046-2069

e-ISSN

—

Svazek periodika

6

Číslo periodika v rámci svazku

16

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

8

Strana od-do

12885-12892

Kód UT WoS článku

000369546100020

EID výsledku v databázi Scopus

2-s2.0-84956935392