Nanomechanical characterization of alumina coatings grown on FeCrAl alloy by thermal oxidation

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A21230%2F16%3A00304014" target="_blank" >RIV/68407700:21230/16:00304014 - isvavai.cz</a>

Výsledek na webu

<a href="http://dx.doi.org/10.1016/j.jmbbm.2016.01.027" target="_blank" >http://dx.doi.org/10.1016/j.jmbbm.2016.01.027</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.jmbbm.2016.01.027" target="_blank" >10.1016/j.jmbbm.2016.01.027</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Nanomechanical characterization of alumina coatings grown on FeCrAl alloy by thermal oxidation

Popis výsledku v původním jazyce

This work studies the feasibility of using repetitive-nano-impact tests with a cube-corner tip and low loads for obtaining quantitative fracture toughness values in thin and brittle coatings. For this purpose, it will be assumed that the impacts are able to produce a cracking, similar to the pattern developed for the classical fracture toughness tests in bulk materials, and therefore, from the crack developed in the repetitive impacts it will be possible to evaluate the suitability of the classical indentation models (Anstins and Laugier) for measuring fracture toughness. However, the length of this crack has to be lower than 10% of the total coating thickness to avoid substrate contributions. For this reason, and in order to ensure a small plastic region localized at the origin of the crack tip, low load values (or small distance between the indenter tip and the surface) have to be used. In order to demonstrate the validity of this technique, repetitive-nano-impact will be done in a fine and dense oxide layer (α-Al2O3), which has been developed on the top of oxide dispersion strengthened (ODS) FeCrAl alloys (PM 2000) by thermal oxidation at elevated temperatures. Moreover, it will be shown how it is possible to know with each new impact the crack geometry evolution from Palmqvist crack to half-penny crack, being able to study the proper evolution of the different values of fracture toughness in terms of both indentation models and as a function of the strain rate, ε, decreasing. Thereby, fracture toughness values for α-Al2O3 layer decrease from ~4.40 root m , for high ε value (103 s-1), to ~3.21MPam, for quasi-static ε value (10-3 s-1). On the other hand, ε a new process to obtain fracture toughness values will be analysed, when the classical indentation models are not met.

Název v anglickém jazyce

Nanomechanical characterization of alumina coatings grown on FeCrAl alloy by thermal oxidation

Popis výsledku anglicky

This work studies the feasibility of using repetitive-nano-impact tests with a cube-corner tip and low loads for obtaining quantitative fracture toughness values in thin and brittle coatings. For this purpose, it will be assumed that the impacts are able to produce a cracking, similar to the pattern developed for the classical fracture toughness tests in bulk materials, and therefore, from the crack developed in the repetitive impacts it will be possible to evaluate the suitability of the classical indentation models (Anstins and Laugier) for measuring fracture toughness. However, the length of this crack has to be lower than 10% of the total coating thickness to avoid substrate contributions. For this reason, and in order to ensure a small plastic region localized at the origin of the crack tip, low load values (or small distance between the indenter tip and the surface) have to be used. In order to demonstrate the validity of this technique, repetitive-nano-impact will be done in a fine and dense oxide layer (α-Al2O3), which has been developed on the top of oxide dispersion strengthened (ODS) FeCrAl alloys (PM 2000) by thermal oxidation at elevated temperatures. Moreover, it will be shown how it is possible to know with each new impact the crack geometry evolution from Palmqvist crack to half-penny crack, being able to study the proper evolution of the different values of fracture toughness in terms of both indentation models and as a function of the strain rate, ε, decreasing. Thereby, fracture toughness values for α-Al2O3 layer decrease from ~4.40 root m , for high ε value (103 s-1), to ~3.21MPam, for quasi-static ε value (10-3 s-1). On the other hand, ε a new process to obtain fracture toughness values will be analysed, when the classical indentation models are not met.

Druh

J_x - Nezařazeno - Článek v odborném periodiku (Jimp, Jsc a Jost)

CEP obor

JG - Hutnictví, kovové materiály

OECD FORD obor

—

Projekt

<a href="/cs/project/GP14-32801P" target="_blank" >GP14-32801P: Nový způsob přípravy metalických vrstev pro aplikace v medicíně</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2016

Kód důvěrnosti údajů

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

Název periodika

Journal of the Mechanical Behavior of Biomedical Materials

ISSN

1751-6161

e-ISSN

—

Svazek periodika

57

Číslo periodika v rámci svazku

April

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

11

Strana od-do

310-320

Kód UT WoS článku

000373655500028

EID výsledku v databázi Scopus

2-s2.0-84957574132