Degradation processes in high-temperature creep of cast cobalt-based superalloys

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68081723%3A_____%2F18%3A00492304" target="_blank" >RIV/68081723:_____/18:00492304 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/60193247:_____/18:N0000014

Výsledek na webu

<a href="http://dx.doi.org/10.1016/j.matchar.2018.08.006" target="_blank" >http://dx.doi.org/10.1016/j.matchar.2018.08.006</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.matchar.2018.08.006" target="_blank" >10.1016/j.matchar.2018.08.006</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Degradation processes in high-temperature creep of cast cobalt-based superalloys

Popis výsledku v původním jazyce

Degradation processes in high-temperature creep of two cast high-chromium cobalt-based superalloys strengthened by niobium and tantalum for use in the glass industry were analysed via various experimental techniques. Constant load creep tests were conducted at 900, 950 and 1000 °C in a tensile stress range from 40 to 80 MPa. It was found that the CoNb superalloy possesses considerably longer creep life compared to the CoTa superalloy under the same loading conditions. Conversely, the creep ductility of the fractured specimens shows the opposite order of the creep life. The creep behaviour of both superalloys obeys the Monkman-Grant formula indicating that the creep deformation mechanism and fracture processes are mutually interlinked. The homogeneously distributed creep damage of the CoNb superalloy is closely connected with primary carbides and is predominantly initiated either as interface decohesion between the carbide/matrix and carbide eutectics/matrix or by breakage of bulk M23C6 carbides. The dominant type of creep damage in the CoTa superalloy is localized breakage of M23C6 carbides in close proximity of the fracture path. The final brittle fracture in the CoNb superalloy occurs via relatively fast propagation of the longest cracks after the ultimate state of damage is reached. Due to premature fracture, the inherent creep ductility of the CoNb matrix is not exhausted. The final ductile transgranular creep fracture of the CoTa superalloy is caused by a local strain-induced instability of the dislocation microstructure leading to a loss of an external section of specimen (necking).

Název v anglickém jazyce

Degradation processes in high-temperature creep of cast cobalt-based superalloys

Popis výsledku anglicky

Degradation processes in high-temperature creep of two cast high-chromium cobalt-based superalloys strengthened by niobium and tantalum for use in the glass industry were analysed via various experimental techniques. Constant load creep tests were conducted at 900, 950 and 1000 °C in a tensile stress range from 40 to 80 MPa. It was found that the CoNb superalloy possesses considerably longer creep life compared to the CoTa superalloy under the same loading conditions. Conversely, the creep ductility of the fractured specimens shows the opposite order of the creep life. The creep behaviour of both superalloys obeys the Monkman-Grant formula indicating that the creep deformation mechanism and fracture processes are mutually interlinked. The homogeneously distributed creep damage of the CoNb superalloy is closely connected with primary carbides and is predominantly initiated either as interface decohesion between the carbide/matrix and carbide eutectics/matrix or by breakage of bulk M23C6 carbides. The dominant type of creep damage in the CoTa superalloy is localized breakage of M23C6 carbides in close proximity of the fracture path. The final brittle fracture in the CoNb superalloy occurs via relatively fast propagation of the longest cracks after the ultimate state of damage is reached. Due to premature fracture, the inherent creep ductility of the CoNb matrix is not exhausted. The final ductile transgranular creep fracture of the CoTa superalloy is caused by a local strain-induced instability of the dislocation microstructure leading to a loss of an external section of specimen (necking).

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

20501 - Materials engineering

Projekt

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

Návaznosti

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

Rok uplatnění

2018

Kód důvěrnosti údajů

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

Název periodika

Materials Characterization

ISSN

1044-5803

e-ISSN

—

Svazek periodika

144

Číslo periodika v rámci svazku

OCT

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

11

Strana od-do

479-489

Kód UT WoS článku

000447477300049

EID výsledku v databázi Scopus

2-s2.0-85051001566