Алексей Александрович Педаш, Павел Александрович Касай, Владимир Валериевич Клочихин, Валерий Григорьевич Шило


Results of low cycle fatigue (LCF) testing, investigation of microstructure, and fractures of specimens, which was, obtain by selective laser melting process (SLM) of the powders from Inconel 718 alloy have been carried out in the present article. Chemical composition of the considered specimens, microstructure before and after testing, results at room and elevated temperatures, which were built in XY direction (horizontal), were carrying-out. The specimens in the as-build state were exposed by hot isostatic pressing (HIP) with subsequent inherent Inconel 718 heat treatment. It was established that in specimens in as-built state observe accurately expressed zones of layer-by-layer smelting with 100 μm height. After HIP with subsequent heat treatment strengthening of the considered alloy provides by intermetallic γ'' – Ni3Nb phase, γ'-phase and carbides, also was identified lamellar δ-phase in the microstructure. LCF-testing was conducted in a so-called «soft» cycle of loading with a predetermined interval of the strain for providing of fatigue life in 103, 5х103, 104 cycles. The obtained data was built logarithmic curve in coordinates «Strain σ – Number of cycles N», that allows, with sufficient reliability, determine a rational strain level at LCF-testing for providing a predetermined number of cycles. The following ratios of σ – N were established (Rσ=0, υ=1 Hz): for providing N=103, σ≤1020 МPа, N=5х103, σ=931…961 МPа, N= 104, σ≤941 МPа. Results of the fractures investigation after LCF-testing at 20°С and 550°С shows that during the cyclic elastoplastic deformation at room temperature multicentricity of crack initiations zones observes. Mainly fixed a viscous pattern of fracture with a fatigue grooves presence, which size increases in the process of crack advance to the zone of fracture area. At elevated temperature in the zones of fatigue crack initiation and spreading quasi-brittle character of destruction observes, and turns in viscous in the zone of fracture area. Authors should be pointed out that the application of additive technologies in the manufacture of aerospace parts requires extensive R&D works, and testing efforts to confirm the repeatability of alloy characteristics. 


superalloy; low cycle fatigue; additive technologies; selective laser melting; hot isostatic pressing; heat-treatment


Zlenko, М. А. et all. Аdditivnyie tekhnologii v mashinostoyenii [Additive manufacturing in machinebuilding]. Sankt Petersburg, Polytechnic university publishing Publ., 2013. 222 p.

Pedash, A. A., Lysenko, N. A, Klochikhin, V. V., Shylo, V. G. Struktura I svoistva obraztcov iz splava Inconel 718 poluchennykh po tehnologii lazernogo plavleniya [Structure and properties of specimens made from Inconel 718 by selective laser melting process]. Aviacijno-kosmichna tehnika i tehnologia –Aerospace technic and technology, 2017, no. 8 (143), pp. 46-54.

Pedash, A. A., Klochikhin, V. V., Lysenko, N. A., Shylo, V. G., Kasay, P. A. Vliyaniye tehnologiy izgotovlenija metallicheskih poroshkov na strukturu I svoistva detaley, poluchennyh selektivnym lazernym plavleniyen [Influence of the powder manufacturing technique on the structure and properties of the SLM-parts]. Visnik dvigunobuduvannia – Herald of aeroenginebuilding, 2019, no. 2, pp. 31-39.

Campanelli, S. L., Contuzzi, N., Angelastro, A., Ludovico, A. Capabilities and Performances of the Selective Laser Melting process. New trends in Technologies: Devices, Computer, Communication and Industrial Systems, 2010, pp. 233-252.

Trosch, T., Strößner, J., Völkl, R., Glatzel, U. Microstructure and mechanical properties of selective laser melted Inconel 718 compared to forging and casting. Materials Letters, 2016, no. 164, pp. 428–431.

GE’s Additive Manufacturing (3D Printing) Research Center. Available at: (accessed 08.06.2020).

Razrabotka tehnologii izgotovleniya zavihritelya frontovogo ustroystva kamery sgoraniya perspertivnogo dvigatelya PD-14 Informatzionnoye soobsheniye. [Development of the manufacturing process for a front burner unit swirler for next generation aero engine PD-14]. Аviatsionnyie materialy i tеhnologii – Aerospace materials and technologies, 2014, no. 5, pp. 101-102.

Kablov, E. N., Evgenov, A. G., Ospennikova, O. G., Semenov, B. I. Semenov, A. B., Korolev, V. A. Metalloporoshkovyye kompozicii zharoprochnogo splava EP648 proizvodstva FGUP VIAM GNC RF v technologiyah selectivnogo lazernogo splavleniya, lazernoy gazoporoshkovoy naplavki I vysokotochnogo litya polimerov napolnennyh metallicheskimi poroshkami [Metal Power Compositions for the EP648 Heat Resistant Alloy Manufactured by All-Russian Research Institute for Aircraft Materials VIAM for Selective Laser Melting, Laser Metal Deposition and Metal Injection Molding Technologies]. Izvestiya vyschyh uchebnyh zavedeniy – Proceedings of higher educational institutions. Mechanical engineering, 2016, no. 9 (678), pp. 62-79.

Cowles, B. A. High cycle fatigue in aircraft gas turbine – an industry perspective. Int. Journal of Fracture. 1996, no. 80, pp. 147–163.

Golubovsky, E. R., Volkov, M. E. Ustalost’ monokristalov nikelevyh splavov VZHM-4 I VZHM-5 pri povyshennyh temperaturah [Fatigue of single crystal NI-based superalloy VZHM-4 and VZHM-5 at elevated temperatures]. Аviatzionnyje dvigateli –Aviaengines. 2018. no. 1. pp. 51-58.


Copyright (c) 2020 Алексей Александрович Педаш, Павел Александрович Касай, Владимир Валериевич Клочихин, Валерий Григорьевич Шило