Thermal creep fracture of a Zr1%Nb cladding alloy in the α and ( α+ β) phase regions

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68081723%3A_____%2F21%3A00542530" target="_blank" >RIV/68081723:_____/21:00542530 - isvavai.cz</a>

Výsledek na webu

<a href="https://www.sciencedirect.com/science/article/pii/S0022311521001732?via%3Dihub" target="_blank" >https://www.sciencedirect.com/science/article/pii/S0022311521001732?via%3Dihub</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.jnucmat.2021.152950" target="_blank" >10.1016/j.jnucmat.2021.152950</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Thermal creep fracture of a Zr1%Nb cladding alloy in the α and ( α+ β) phase regions

Popis výsledku v původním jazyce

The objective of the present study was to provide new relevant information on creep behaviour and fracture processes in a sponge-based modified Zr1%Nb cladding alloy (modified E110 alloy) in the α-Zr and (α+β)-Zr phase regions. To this end, constant load creep tests were carried out in argon at testing temperature intervals from 350°C to 950°C, and applied tensile stresses ranging from 5 MPa to 210 MPa, corresponding to the power-law breakdown creep regime and/or high testing temperatures, and thus to simulate disaster conditions. Creep tests were followed by nmetallographic and fractographic analyses of the specimens to explain the observed creep behaviour. It was found that in the power-law region (at 350°C) the values of the stress nexponent n of the minimum creep rate ε˙ m (n = ∂lnε˙ m /∂lnσ )T , and the stress exponent m of the time to fracture tf (m = - ∂lntf /∂lnσ )T, were very high and near to each other, indicating a nclose relationship between creep deformation and fracture. Further support for the idea that creep deformation and fracture are interconnected can be observed by the validity of the em- npirical Monkman-Grant relationship. Creep tests in the α-Zr phase region revealed creep cavitation near to, and at, the fracture surface. The final fracture is a ductile dimple mode with the nsynergistic effect of creep cavitation. By contrast, the final fracture in the (α+β)-Zr phase region is caused by a local strain- induced instability of the matrix leading to a loss of an external nsection of specimen (necking). There is a marked difference between the values of the strain to fracture εf . In the α-Zr region, typical values of εf ~ 0.3-0.5 were found, whereas for the n(α+β)-Zr region, the value εf increases with testing temperature up to 850°C. Following drop of εf at temperatures ≥ 900°C was explain by intensive oxidation of the alloy.n

Název v anglickém jazyce

Thermal creep fracture of a Zr1%Nb cladding alloy in the α and ( α+ β) phase regions

Popis výsledku anglicky

The objective of the present study was to provide new relevant information on creep behaviour and fracture processes in a sponge-based modified Zr1%Nb cladding alloy (modified E110 alloy) in the α-Zr and (α+β)-Zr phase regions. To this end, constant load creep tests were carried out in argon at testing temperature intervals from 350°C to 950°C, and applied tensile stresses ranging from 5 MPa to 210 MPa, corresponding to the power-law breakdown creep regime and/or high testing temperatures, and thus to simulate disaster conditions. Creep tests were followed by nmetallographic and fractographic analyses of the specimens to explain the observed creep behaviour. It was found that in the power-law region (at 350°C) the values of the stress nexponent n of the minimum creep rate ε˙ m (n = ∂lnε˙ m /∂lnσ )T , and the stress exponent m of the time to fracture tf (m = - ∂lntf /∂lnσ )T, were very high and near to each other, indicating a nclose relationship between creep deformation and fracture. Further support for the idea that creep deformation and fracture are interconnected can be observed by the validity of the em- npirical Monkman-Grant relationship. Creep tests in the α-Zr phase region revealed creep cavitation near to, and at, the fracture surface. The final fracture is a ductile dimple mode with the nsynergistic effect of creep cavitation. By contrast, the final fracture in the (α+β)-Zr phase region is caused by a local strain- induced instability of the matrix leading to a loss of an external nsection of specimen (necking). There is a marked difference between the values of the strain to fracture εf . In the α-Zr region, typical values of εf ~ 0.3-0.5 were found, whereas for the n(α+β)-Zr region, the value εf increases with testing temperature up to 850°C. Following drop of εf at temperatures ≥ 900°C was explain by intensive oxidation of the alloy.n

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

20501 - Materials engineering

Projekt

<a href="/cs/project/TH02020477" target="_blank" >TH02020477: Experimentální výzkum a matematická simulace chování modifikovaného palivového pokrytí v podmínkách havárie LOCA</a><br>

Návaznosti

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

Rok uplatnění

2021

Kód důvěrnosti údajů

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

Název periodika

Journal of Nuclear Materials

ISSN

0022-3115

e-ISSN

1873-4820

Svazek periodika

553

Číslo periodika v rámci svazku

SEP

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

15

Strana od-do

152950

Kód UT WoS článku

000663796000005

EID výsledku v databázi Scopus

2-s2.0-85106345574