Low cycle fatigue performance of Ni-based superalloy coated with complex thermal barrier coating

Journal Article · Tue May 15 04:00:00 EDT 2018 · Materials Characterization

DOI:https://doi.org/10.1016/J.MATCHAR.2018.03.023· OSTI ID:22804993

Ivo, Sulak; Karel, Obrtlik ^[1]; Ladislav, Celko ^[2]; Tomáš, Chraska ^[3]; Jech, David; Pavel, Gejdos ^[2]

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1. Institute of Physics of Materials, Academy of Sciences of the Czech Republic, Žižkova 22, 616 62 Brno (Czech Republic)
2. CEITEC – Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 612 00 Brno (Czech Republic)
3. Institute of Plasma Physics, Academy of Sciences of the Czech Republic, Za Slovankou 3, 182 00 Praha (Czech Republic)

Highlights: • Novel thermal barrier coating (TBC) with YSZ and ZrO{sub 2} + SiO{sub 2} + Al{sub 2}O{sub 3} eutectic ceramic top coat • TBC deposited via atmospheric plasma spraying and a hybrid water stabilized plasma torch spraying • Effect of eutectic ceramic TBC on LCF behaviour at 900 °C • Damage mechanisms in cyclic loading of cast nickel-based superalloy coated with TBC • The dislocation structures of a Ni-base superalloy were observed. - Abstract: Thermal barrier coatings (TBCs) are widely applied to protect high-temperature components against high temperatures in harsh environments. Nineteen cylindrical specimens of Inconel 713LC were manufactured using the investment castings technique, and 10 specimens were subsequently coated with a novel complex thermal barrier coating (TBC) system. The TBC system comprises a metallic CoNiCrAlY bond coat (BC) and a complex ceramic top coat (TC). The TC is a mixture of a near eutectic nanocrystalline ceramic made of zirconia (ZrO{sub 2}), alumina (Al{sub 2}O{sub 3}), silica (SiO{sub 2}) and conventional yttria stabilized zirconia (YSZ) ceramic in the ratio of 50/50 in wt%. Low cycle fatigue (LCF) tests were carried out in a symmetrical push-pull cycle under strain control at 900 °C. Cyclic hardening/softening curves, cyclic stress-strain curves and fatigue life curves of the TBC-coated and uncoated material were assessed. Fatigue life curves in total strain representation showed transient behaviour. Fracture surfaces and polished sections parallel to the loading axis of the TBC-coated and uncoated specimens prior and after cyclic loading were observed by means of scanning electron microscopy (SEM) to study the degradation mechanisms during high-temperature LCF. TBC delamination was observed at the TC/BC interface, and rafting of precipitates occurred after high-temperature exposure. The microstructural investigations further the discussion of the differences in the stress-strain response and the fatigue life of the TBC-coated and uncoated superalloy.

• OSTI ID: 22804993
• Journal Information: Materials Characterization, Journal Name: Materials Characterization Vol. 139; ISSN 1044-5803; ISSN MACHEX
• Country of Publication: United States
• Language: English

Related Subjects

77 NANOSCIENCE AND NANOTECHNOLOGY
ALUMINIUM OXIDES
CERAMICS
CRYSTALS
DISLOCATIONS
EUTECTICS
INCONEL 713LC
INTERFACES
MICROSTRUCTURE
NANOSTRUCTURES
NICKEL BASE ALLOYS
PRECIPITATION
SCANNING ELECTRON MICROSCOPY
SILICON OXIDES
STRESSES
YTTRIUM OXIDES
ZIRCONIUM OXIDES