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

0491914 - ÚFM 2019 RIV US eng J - Článek v odborném periodiku
Šulák, Ivo - Obrtlík, Karel - Čelko, L. - Chráska, Tomáš - Jech, D. - Gejdoš, P.
Low cycle fatigue performance of Ni-based superalloy coated with complex thermal barrier coating.
Materials Characterization. Roč. 139, MAY (2018), s. 347-354. ISSN 1044-5803. E-ISSN 1873-4189
Grant CEP: GA ČR(CZ) GA15-20991S
Institucionální podpora: RVO:68081723 ; RVO:61389021
Klíčová slova: Inconel 713LC * Thermal barrier coating * High-temperature low cycle fatigue * Cyclic stress-strain curve * Fatigue live curves * Degradation mechanisms
Obor OECD: Audio engineering, reliability analysis; Audio engineering, reliability analysis (UFP-V)
Impakt faktor: 3.220, rok: 2018

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 (ZrO2), alumina (Al2O3), silica (SiO2) 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.
Trvalý link: http://hdl.handle.net/11104/0286823