Studies of Post-Fabrication Heat Treatment of L-PBF-Inconel 718: Effects of Hold Time on Microstructure, Annealing Twins, and Hardness
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...
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| Format: | Article |
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MDPI AG
2021-02-01
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| Series: | Metals |
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| Online Access: | https://www.mdpi.com/2075-4701/11/2/266 |
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| author | Wakshum M. Tucho Vidar Hansen |
| author_facet | Wakshum M. Tucho Vidar Hansen |
| author_sort | Wakshum M. Tucho |
| collection | DOAJ |
| description | 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. |
| first_indexed | 2024-03-09T05:44:54Z |
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| id | doaj.art-3497fd2aad594caab5e81e02e656d9ba |
| institution | Directory Open Access Journal |
| issn | 2075-4701 |
| language | English |
| last_indexed | 2024-03-09T05:44:54Z |
| publishDate | 2021-02-01 |
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| spelling | doaj.art-3497fd2aad594caab5e81e02e656d9ba2023-12-03T12:21:52ZengMDPI AGMetals2075-47012021-02-0111226610.3390/met11020266Studies of Post-Fabrication Heat Treatment of L-PBF-Inconel 718: Effects of Hold Time on Microstructure, Annealing Twins, and HardnessWakshum M. Tucho0Vidar Hansen1Department of Mechanical and Structural Engineering and Materials Science, Faculty of Science and Technology, University of Stavanger, 4036 Stavanger, NorwayDepartment of Mechanical and Structural Engineering and Materials Science, Faculty of Science and Technology, University of Stavanger, 4036 Stavanger, NorwayThe 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.https://www.mdpi.com/2075-4701/11/2/266laser metal powder bed fusion (L-PBF)Inconel 718microstructurehardnessheat treatmentrecrystallization |
| spellingShingle | Wakshum M. Tucho Vidar Hansen Studies of Post-Fabrication Heat Treatment of L-PBF-Inconel 718: Effects of Hold Time on Microstructure, Annealing Twins, and Hardness Metals laser metal powder bed fusion (L-PBF) Inconel 718 microstructure hardness heat treatment recrystallization |
| title | Studies of Post-Fabrication Heat Treatment of L-PBF-Inconel 718: Effects of Hold Time on Microstructure, Annealing Twins, and Hardness |
| title_full | Studies of Post-Fabrication Heat Treatment of L-PBF-Inconel 718: Effects of Hold Time on Microstructure, Annealing Twins, and Hardness |
| title_fullStr | Studies of Post-Fabrication Heat Treatment of L-PBF-Inconel 718: Effects of Hold Time on Microstructure, Annealing Twins, and Hardness |
| title_full_unstemmed | Studies of Post-Fabrication Heat Treatment of L-PBF-Inconel 718: Effects of Hold Time on Microstructure, Annealing Twins, and Hardness |
| title_short | Studies of Post-Fabrication Heat Treatment of L-PBF-Inconel 718: Effects of Hold Time on Microstructure, Annealing Twins, and Hardness |
| title_sort | studies of post fabrication heat treatment of l pbf inconel 718 effects of hold time on microstructure annealing twins and hardness |
| topic | laser metal powder bed fusion (L-PBF) Inconel 718 microstructure hardness heat treatment recrystallization |
| url | https://www.mdpi.com/2075-4701/11/2/266 |
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