Effects of temperature and strain rate on isothermal low-cycle fatigue behaviour of Inconel 718 superalloy: Damage mechanisms, microstructure evolution, and life prediction

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68081723%3A_____%2F25%3A00619415" target="_blank" >RIV/68081723:_____/25:00619415 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/68407700:21220/25:00384522

Výsledek na webu

<a href="https://www.webofscience.com/wos/woscc/full-record/WOS:001488516100001" target="_blank" >https://www.webofscience.com/wos/woscc/full-record/WOS:001488516100001</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.ijfatigue.2025.109005" target="_blank" >10.1016/j.ijfatigue.2025.109005</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Effects of temperature and strain rate on isothermal low-cycle fatigue behaviour of Inconel 718 superalloy: Damage mechanisms, microstructure evolution, and life prediction

Popis výsledku v původním jazyce

In this article, strain-controlled Low-Cycle Fatigue (LCF) tests were performed on Inconel 718 nickel-based superalloy at temperatures of 300 ◦C, 650 ◦C, and 730 ◦C. The LCF tests were conducted at various mechanical strain amplitudes between 3.5×10−3 and 1×10−2, and three different mechanical strain rates: 1×10−4/s, 1×10−3/s, and 1×10−2/s. Cyclic straining resulted in cyclic softening under all investigated loading conditions, with the effect being more significant at higher temperatures. The cyclic softening was attributed to the formation of persistent slip bands and the shearing of coherent precipitates. At 730 ◦C, delta phase precipitation in LCF tests conducted at low strain rates contributed to additional softening. Investigations into the damage mechanisms revealed that the predominant failure mode shifted from transgranular at 300 ◦C to intergranular at 650 ◦C and 730 ◦C. In addition, fatigue crack initiation sites most frequently involved broken or oxidized carbides. The fatigue lifetime decreased with an increasing temperature and a decreasing strain rate, primarily due to oxidation-assisted intergranular cracking at high temperatures, involving the formation of brittle oxides at grain boundaries. Finally, a multi-mechanism-based damage model was proposed to predict fatigue lifetime, accounting for contributions from oxidation, creep, and fatigue damage. The model exhibited a good correlation between the predicted and the observed lifetimes.

Název v anglickém jazyce

Effects of temperature and strain rate on isothermal low-cycle fatigue behaviour of Inconel 718 superalloy: Damage mechanisms, microstructure evolution, and life prediction

Popis výsledku anglicky

In this article, strain-controlled Low-Cycle Fatigue (LCF) tests were performed on Inconel 718 nickel-based superalloy at temperatures of 300 ◦C, 650 ◦C, and 730 ◦C. The LCF tests were conducted at various mechanical strain amplitudes between 3.5×10−3 and 1×10−2, and three different mechanical strain rates: 1×10−4/s, 1×10−3/s, and 1×10−2/s. Cyclic straining resulted in cyclic softening under all investigated loading conditions, with the effect being more significant at higher temperatures. The cyclic softening was attributed to the formation of persistent slip bands and the shearing of coherent precipitates. At 730 ◦C, delta phase precipitation in LCF tests conducted at low strain rates contributed to additional softening. Investigations into the damage mechanisms revealed that the predominant failure mode shifted from transgranular at 300 ◦C to intergranular at 650 ◦C and 730 ◦C. In addition, fatigue crack initiation sites most frequently involved broken or oxidized carbides. The fatigue lifetime decreased with an increasing temperature and a decreasing strain rate, primarily due to oxidation-assisted intergranular cracking at high temperatures, involving the formation of brittle oxides at grain boundaries. Finally, a multi-mechanism-based damage model was proposed to predict fatigue lifetime, accounting for contributions from oxidation, creep, and fatigue damage. The model exhibited a good correlation between the predicted and the observed lifetimes.

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

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2025

Kód důvěrnosti údajů

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

Název periodika

International Journal of Fatigue

ISSN

0142-1123

e-ISSN

1879-3452

Svazek periodika

198

Číslo periodika v rámci svazku

Sept

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

19

Strana od-do

109005

Kód UT WoS článku

001488516100001

EID výsledku v databázi Scopus

2-s2.0-105003995909