Monovacancy-hydrogen interaction in pure aluminum: Experimental and ab-initio theoretical positron annihilation study

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F23%3A10475224" target="_blank" >RIV/00216208:11320/23:10475224 - isvavai.cz</a>

Výsledek na webu

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=ZrJV9M.GAq" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=ZrJV9M.GAq</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.actamat.2023.118770" target="_blank" >10.1016/j.actamat.2023.118770</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Monovacancy-hydrogen interaction in pure aluminum: Experimental and ab-initio theoretical positron annihilation study

Popis výsledku v původním jazyce

We report here on hydrogen-vacancy interactions in high purity aluminum by employing positron annihilation spectroscopy (PAS) analysis of hydrogen-loaded samples, aiming to study the mobility of vacancies. The samples were heat treated at 893 K in an atmosphere consisting of a mixture of H2 and Ar gas and, thus, loaded with hydrogen. The samples were then quenched to ice water and subsequently measured in-situ at different tem-peratures. In parallel we performed ab-initio density functional theory (DFT) calculations of lifetimes of positrons trapped in vacancies associated with 1-8 H atoms. Our experimental results suggest in comparison with the ab-initio calculations that complexes of vacancies with one hydrogen atom (V-H pairs) were formed in Al samples annealed in a mixture of H2 and Ar gas. Furthermore, hydrogen absorbed in aluminum immobilizes vacancies, i. e. the recovery of vacancies is delayed from 220 K up to around 280 K. At that temperature, V-H complexes start to dissociate, and hydrogen atoms previously bound to vacancies are released. In contrast, for Al samples not loaded with hydrogen isolated monovacancies become mobile around 220 K. In both cases mobile vacancies start to form vacancy clusters. From our experimental data we determined that the formation energy of mono-vacancies in Al is 0.62 +/- 0.01 eV. This value is in very good agreement with 0.63 eV obtained by our ab-initio DFT calculations.

Název v anglickém jazyce

Monovacancy-hydrogen interaction in pure aluminum: Experimental and ab-initio theoretical positron annihilation study

Popis výsledku anglicky

We report here on hydrogen-vacancy interactions in high purity aluminum by employing positron annihilation spectroscopy (PAS) analysis of hydrogen-loaded samples, aiming to study the mobility of vacancies. The samples were heat treated at 893 K in an atmosphere consisting of a mixture of H2 and Ar gas and, thus, loaded with hydrogen. The samples were then quenched to ice water and subsequently measured in-situ at different tem-peratures. In parallel we performed ab-initio density functional theory (DFT) calculations of lifetimes of positrons trapped in vacancies associated with 1-8 H atoms. Our experimental results suggest in comparison with the ab-initio calculations that complexes of vacancies with one hydrogen atom (V-H pairs) were formed in Al samples annealed in a mixture of H2 and Ar gas. Furthermore, hydrogen absorbed in aluminum immobilizes vacancies, i. e. the recovery of vacancies is delayed from 220 K up to around 280 K. At that temperature, V-H complexes start to dissociate, and hydrogen atoms previously bound to vacancies are released. In contrast, for Al samples not loaded with hydrogen isolated monovacancies become mobile around 220 K. In both cases mobile vacancies start to form vacancy clusters. From our experimental data we determined that the formation energy of mono-vacancies in Al is 0.62 +/- 0.01 eV. This value is in very good agreement with 0.63 eV obtained by our ab-initio DFT calculations.

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

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2023

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

248

Číslo periodika v rámci svazku

15 April 2023

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

14

Strana od-do

118770

Kód UT WoS článku

000995002900001

EID výsledku v databázi Scopus

2-s2.0-85149057399