SYMPOSIA PAPER Published: 05 June 2020
STP162020180108

Role of Post-Fabrication Heat Treatment on the Low-Cycle Fatigue Behavior of Electron Beam Melted Inconel 718 Superalloy

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Inconel 718 (In 718) specimens were fabricated by electron beam melting (EBM) additive manufacturing technique. The performance under monotonic and cyclic loading in the low-cycle fatigue regime at ambient temperature was studied. Two different conditions were considered: as-built and solution-treated and aged. All investigations were carried out on samples with machined and ground surfaces. The results revealed microstructures containing large elongated grains with a strong fiber texture 〈001〉 || BD for both conditions. Generally, the EBM Inconel 718 is characterized by high hardness and strength in the as-built state, whereas the post-process heat treatment results in a slight increase in hardness. Mechanical properties can be correlated to the fraction of strengthening phases. In terms of stress amplitudes and fatigue lives, the cyclic deformation response for both conditions is similar. Fracture surface analysis revealed crack initiation in the direct vicinity of the surfaces of the fatigued samples. The results of the current study indicate that the characteristics of the EBM process—that is, high-process temperatures and intrinsic heat treatment—potentially could pave the way for an elimination of any resource intensive post-processing treatment of Inconel 718, even in the case of cyclically loaded components.

Author Information

Wegener, Thomas
Institut für Werkstofftechnik (Materials Engineering), Universität Kassel, Kassel, DE
Günther, Johannes
Institut für Werkstofftechnik (Materials Engineering), Universität Kassel, Kassel, DE
Brenne, Florian
Institut für Werkstofftechnik (Materials Engineering), Universität Kassel, Kassel, DE Dept. of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, US
Niendorf, Thomas
Institut für Werkstofftechnik (Materials Engineering), Universität Kassel, Kassel, DE
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Developed by Committee: F42
Pages: 465–483
DOI: 10.1520/STP162020180108
ISBN-EB: 978-0-8031-7687-4
ISBN-13: 978-0-8031-7686-7