Two-phase model for inverse Hall-Petch effect in nanocrystalline thin film: Atomistic simulation study

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216305%3A26620%2F24%3APU152471" target="_blank" >RIV/00216305:26620/24:PU152471 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/68081723:_____/24:00586888 RIV/00216208:11320/24:10484637

Výsledek na webu

<a href="https://www.sciencedirect.com/science/article/pii/S135964542400435X?via%3Dihub" target="_blank" >https://www.sciencedirect.com/science/article/pii/S135964542400435X?via%3Dihub</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.actamat.2024.120084" target="_blank" >10.1016/j.actamat.2024.120084</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Two-phase model for inverse Hall-Petch effect in nanocrystalline thin film: Atomistic simulation study

Popis výsledku v původním jazyce

This work presents two methods to improve the understanding of the mechanical behavior of nanocrystalline thin films. Firstly, a simple two-phase model is proposed to explain the inverse Hall-Petch effect. The model suggests that the nanocrystalline material consists of the grain -boundary and the grain interior with different mechanical properties. Secondly, a computational method is developed to create more realistic grain boundaries in simulations of polycrystals. Traditionally created grain boundaries by Voronoi tessellation are too dense and do not accurately reflect the reality and the experimental results. The strength of the nanocrystalline aluminum thin film is simulated using molecular dynamics. The grain size dependence of the elastic modulus, ultimate tensile stress, and engineering yield strength is demonstrated. The experimental values of modulus and strength are approximately 6 times smaller probably due to the presence of porosity in the real sample. An approach is developed to introduce porosity in the simulated samples at the grain boundaries and in the grain interior to reduce this discrepancy. The modeled value of modulus for a grain size of 40 nm without porosity is 67 GPa, whereas, with 50% grain -boundary porosity and 20% intra-granular porosity it is 30 GPa. For the ultimate tensile strength, we get 3 GPa and 1.4 GPa for samples without porosity and with porosity, respectively. The simulated values of modulus with porosity are still 4 times higher and the values of strength are about 2 times higher than the experimental ones. The amount of porosity in our method can be adjusted to fit the experimental values; however, high values of porosity cause the mechanical instability of the simulated samples.

Název v anglickém jazyce

Two-phase model for inverse Hall-Petch effect in nanocrystalline thin film: Atomistic simulation study

Popis výsledku anglicky

This work presents two methods to improve the understanding of the mechanical behavior of nanocrystalline thin films. Firstly, a simple two-phase model is proposed to explain the inverse Hall-Petch effect. The model suggests that the nanocrystalline material consists of the grain -boundary and the grain interior with different mechanical properties. Secondly, a computational method is developed to create more realistic grain boundaries in simulations of polycrystals. Traditionally created grain boundaries by Voronoi tessellation are too dense and do not accurately reflect the reality and the experimental results. The strength of the nanocrystalline aluminum thin film is simulated using molecular dynamics. The grain size dependence of the elastic modulus, ultimate tensile stress, and engineering yield strength is demonstrated. The experimental values of modulus and strength are approximately 6 times smaller probably due to the presence of porosity in the real sample. An approach is developed to introduce porosity in the simulated samples at the grain boundaries and in the grain interior to reduce this discrepancy. The modeled value of modulus for a grain size of 40 nm without porosity is 67 GPa, whereas, with 50% grain -boundary porosity and 20% intra-granular porosity it is 30 GPa. For the ultimate tensile strength, we get 3 GPa and 1.4 GPa for samples without porosity and with porosity, respectively. The simulated values of modulus with porosity are still 4 times higher and the values of strength are about 2 times higher than the experimental ones. The amount of porosity in our method can be adjusted to fit the experimental values; however, high values of porosity cause the mechanical instability of the simulated samples.

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

2024

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

276

Číslo periodika v rámci svazku

120084

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

10

Strana od-do

„“-„“

Kód UT WoS článku

001255515100001

EID výsledku v databázi Scopus

2-s2.0-85195677607