Effect of casting conditions and heat treatment on high temperature low cycle fatigue performance of nickel superalloy Inconel 713LC

0522253 - ÚFM 2021 RIV CZ eng C - Conference Paper (international conference)
Šulák, Ivo - Obrtlík, Karel - Hrbáček, Karel
Effect of casting conditions and heat treatment on high temperature low cycle fatigue performance of nickel superalloy Inconel 713LC.
Metal 2019 - 28th International Conference on Metallurgy and Materials. Ostrava: TANGER Ltd., Ostrava, 2019, s. 1351-1356. ISBN 978-80-87294-92-5.
[METAL 2019. International conference on metallurgy and materials /28./. Brno (CZ), 22.05.2019-24.05.2019]
R&D Projects: GA MPO(CZ) EG15_019/0002421
Institutional support: RVO:68081723
Keywords : Inconel 713LC * vibratory investment casting * hot isostatic pressing * high temperature low cycle fatigue * stress-strain response
OECD category: Audio engineering, reliability analysis

The present work is focused on the study of high temperature low cycle fatigue behaviour of Inconel 713LC produced by a vibratory investment casting (VIC) in as-cast conditions and in the condition after heat treatment (HT) consisting of hot isostatic pressing (HIP) followed by precipitation hardening. Low cycle fatigue tests were carried out on cylindrical specimens in symmetrical push-pull cycle under strain control with constant total strain amplitude and strain rate at 800 °C in air. Hardening/softening curves and fatigue life curves of both materials were assessed and compared with data of Inconel 713LC produced by a conventional investment casting (CIC). Cyclic hardening can be observed in the high amplitude domain while saturated stress response is apparent for low amplitude cycling for all material batches. Data presented in Basquin representation show an increase in fatigue life of both VIC batches compared to the CIC batch, however, no effect of HT on fatigue life of Inconel 713LC produced by VIC was observed. In contrast, the heat treated Inconel 713LC demonstrates slightly higher fatigue life in Coffin-Manson representation. The microstructure of both superalloys was studied by means of scanning electron microscopy (SEM). The microstructure of superalloy is characterized by dendritic grains with casting defects. It comprises the γ matrix, cubic γ´ precipitates, eutectics and carbides. The effect of the VIC and HT on fatigue performance and microstructure of Inconel 713LC is discussed.
Permanent Link: http://hdl.handle.net/11104/0309730