0586291 - ÚFM 2025 RIV GB eng J - Journal Article
Bartošák, M. - Horváth, J. - Gálíková, Markéta - Slaný, M. - Šulák, Ivo
High-temperature low-cycle fatigue and fatigue–creep behaviour of Inconel 718 superalloy: Damage and deformation mechanisms.
International Journal of Fatigue. Roč. 186, SEP (2024), č. článku 108369. ISSN 0142-1123. E-ISSN 1879-3452
R&D Projects: GA MŠMT(CZ) EH22_008/0004634
Institutional support: RVO:68081723
Keywords : Low-cycle fatigue * Fatigue–creep * Inconel 718 superalloy * Damage mechanisms * Microstructure
OECD category: Materials engineering
Impact factor: 5.7, year: 2023 ; AIS: 0.931, rok: 2023
Method of publishing: Open access
Result website:
https://www.sciencedirect.com/science/article/pii/S0142112324002275?via%3DihubDOI: https://doi.org/10.1016/j.ijfatigue.2024.108369

In this article, strain-controlled Low-Cycle Fatigue (LCF) and fatigue–creep tests were performed on Inconel
718 nickel-based superalloy at temperatures of 650 ◦C and 730 ◦C. LCF tests at elevated temperatures were
performed with a mechanical strain rate of 1 × 10−3/s, while fatigue–creep tests involved either tensile or
compressive strain dwell. Both the LCF and fatigue–creep tests revealed cyclic softening, with the mean stress
evolving oppositely to the applied strain dwell in the fatigue–creep tests. Investigations into the damage
mechanisms identified intergranular cracking as the predominant failure mode. Fatigue–creep loading with
a compressive dwell resulted in multiple crack initiations from transgranular oxide intrusions, along with
multiple creep cavities during loading at 730 ◦C. Deformation features such as persistent slip bands and
deformation nanotwins were observed during cycling at 650 ◦C. In addition, fatigue–creep tests at 730 ◦C
exhibited 𝛿 phase precipitation and a coarsening of strengthening precipitates, contributing to additional
softening that increased over prolonged test durations. Finally, the observed lifetime during LCF tests decreased
with increasing temperatures, and fatigue–creep loading was observed to be more damaging than LCF. On the
other hand, fatigue–creep loading with a tensile strain dwell demonstrated a higher lifetime compared to LCF
at 730 ◦C.
Permanent Link: https://hdl.handle.net/11104/0353855
Research data: Zenodo