Next Article in Journal
Additive Manufacturing of Titanium with Different Surface Structures for Adhesive Bonding and Thermal Direct Joining with Fiber-Reinforced Polyether-Ether-Ketone (PEEK) for Lightweight Design Applications
Previous Article in Journal
Effect of Thermal Debinding Conditions on the Sintered Density of Low-Pressure Powder Injection Molded Iron Parts
Article

Studies of Post-Fabrication Heat Treatment of L-PBF-Inconel 718: Effects of Hold Time on Microstructure, Annealing Twins, and Hardness

Department of Mechanical and Structural Engineering and Materials Science, Faculty of Science and Technology, University of Stavanger, 4036 Stavanger, Norway
*
Author to whom correspondence should be addressed.
Academic Editor: Maciej Motyka
Metals 2021, 11(2), 266; https://doi.org/10.3390/met11020266
Received: 5 January 2021 / Revised: 22 January 2021 / Accepted: 29 January 2021 / Published: 4 February 2021
(This article belongs to the Section Additive Manufacturing)
The widely adopted temperature for solid solution heat treatment (ST) for the conventionally fabricated Inconel 718 is 1100 °C for a hold time of 1 h or less. This ST scheme is, however, not enough to dissolve Laves and annihilate dislocations completely in samples fabricated with Laser metal powder bed fusion (L-PBF) additive manufacturing (AM)-Inconel 718. Despite this, the highest hardness obtained after aging for ST temperatures (970–1250 °C) is at 1100 °C/1 as we have ascertained in our previous studies. The unreleased residual stresses in the retained lattice defects potentially affect other properties of the material. Hence, this work aims to investigate if a longer hold time of ST at 1100 °C will lead to complete recrystallization while maintaining the hardness after aging or not. For this study, L-PBF-Inconel 718 samples were ST at 1100 °C at various hold times (1, 3, 6, 9, 16, or 24 h) and aged to study the effects on microstructure and hardness. In addition, a sample was directly aged to study the effects of bypassing ST. The samples (ST and aged) gain hardness by 43–49%. The high density of annealing twins evolved during 3 h of ST and only slightly varies for longer ST. View Full-Text
Keywords: laser metal powder bed fusion (L-PBF); Inconel 718; microstructure; hardness; heat treatment; recrystallization; annealing twins laser metal powder bed fusion (L-PBF); Inconel 718; microstructure; hardness; heat treatment; recrystallization; annealing twins
Show Figures

Figure 1

MDPI and ACS Style

Tucho, W.M.; Hansen, V. Studies of Post-Fabrication Heat Treatment of L-PBF-Inconel 718: Effects of Hold Time on Microstructure, Annealing Twins, and Hardness. Metals 2021, 11, 266. https://doi.org/10.3390/met11020266

AMA Style

Tucho WM, Hansen V. Studies of Post-Fabrication Heat Treatment of L-PBF-Inconel 718: Effects of Hold Time on Microstructure, Annealing Twins, and Hardness. Metals. 2021; 11(2):266. https://doi.org/10.3390/met11020266

Chicago/Turabian Style

Tucho, Wakshum M., and Vidar Hansen. 2021. "Studies of Post-Fabrication Heat Treatment of L-PBF-Inconel 718: Effects of Hold Time on Microstructure, Annealing Twins, and Hardness" Metals 11, no. 2: 266. https://doi.org/10.3390/met11020266

Find Other Styles
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop