Determining the Effects of Inter-Layer Time Interval in Powder-Fed Laser-Directed Energy Deposition on the Microstructure of Inconel 718 via In Situ Thermal Monitoring
Cylindrical Inconel 718 specimens were fabricated via a blown-powder, laser-directed energy deposition (DED-L) additive manufacturing (AM) process equipped with a dual thermal monitoring system to learn key process–structure relationships. Thermographic inspection of the heat affected zone (HAZ) and...
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MDPI AG
2024-01-01
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| Online Access: | https://www.mdpi.com/1996-1944/17/3/538 |
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| author | Evan Handler Aref Yadollahi Yucheng Liu Scott M. Thompson |
| author_facet | Evan Handler Aref Yadollahi Yucheng Liu Scott M. Thompson |
| author_sort | Evan Handler |
| collection | DOAJ |
| description | Cylindrical Inconel 718 specimens were fabricated via a blown-powder, laser-directed energy deposition (DED-L) additive manufacturing (AM) process equipped with a dual thermal monitoring system to learn key process–structure relationships. Thermographic inspection of the heat affected zone (HAZ) and melt pool was performed with different layer-to-layer time intervals of ~0 s, 5 s, and 10 s, using an infrared camera and dual-wavelength pyrometer, respectively. Maximum melt pool temperatures were found to increase with layer number within a substrate affected zone (SAZ), and then asymptotically decrease. As the layer-to-layer time interval increased the HAZ temperature responses became more repetitive, indicating a desirable approach for achieving a more homogeneous microstructure along the height of a part. Microstructural variations in grain size and the coexistence of specific precipitate phases and Laves phases persisted among the investigated samples despite the employed standard heat treatment. This indicates that the effectiveness of any post DED-L heat treatment depends significantly on the initial, as-printed microstructure. Overall, this study demonstrates the importance of part size, part number per build, and time intervals on DED-L process parameter selection and post-process heat treatments for achieving better quality control. |
| first_indexed | 2024-03-08T03:54:12Z |
| format | Article |
| id | doaj.art-f1629b9f1dae439baa3f40158230efa0 |
| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-08T03:54:12Z |
| publishDate | 2024-01-01 |
| publisher | MDPI AG |
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| spelling | doaj.art-f1629b9f1dae439baa3f40158230efa02024-02-09T15:16:59ZengMDPI AGMaterials1996-19442024-01-0117353810.3390/ma17030538Determining the Effects of Inter-Layer Time Interval in Powder-Fed Laser-Directed Energy Deposition on the Microstructure of Inconel 718 via In Situ Thermal MonitoringEvan Handler0Aref Yadollahi1Yucheng Liu2Scott M. Thompson3Department of Mechanical Engineering, Mississippi State University, Mississippi State, MS 39762, USADepartment of Mechanical & Civil Engineering, Purdue University Northwest, Hammond, IN 46323, USADepartment of Mechanical Engineering, South Dakota State University, Brookings, SD 57007, USADepartment of Mechanical & Aerospace Engineering, University of Missouri, Columbia, MO 65211, USACylindrical Inconel 718 specimens were fabricated via a blown-powder, laser-directed energy deposition (DED-L) additive manufacturing (AM) process equipped with a dual thermal monitoring system to learn key process–structure relationships. Thermographic inspection of the heat affected zone (HAZ) and melt pool was performed with different layer-to-layer time intervals of ~0 s, 5 s, and 10 s, using an infrared camera and dual-wavelength pyrometer, respectively. Maximum melt pool temperatures were found to increase with layer number within a substrate affected zone (SAZ), and then asymptotically decrease. As the layer-to-layer time interval increased the HAZ temperature responses became more repetitive, indicating a desirable approach for achieving a more homogeneous microstructure along the height of a part. Microstructural variations in grain size and the coexistence of specific precipitate phases and Laves phases persisted among the investigated samples despite the employed standard heat treatment. This indicates that the effectiveness of any post DED-L heat treatment depends significantly on the initial, as-printed microstructure. Overall, this study demonstrates the importance of part size, part number per build, and time intervals on DED-L process parameter selection and post-process heat treatments for achieving better quality control.https://www.mdpi.com/1996-1944/17/3/538additive manufacturinglaser engineered net shapingthermal monitoringquality controlmicrostructuremelt pool |
| spellingShingle | Evan Handler Aref Yadollahi Yucheng Liu Scott M. Thompson Determining the Effects of Inter-Layer Time Interval in Powder-Fed Laser-Directed Energy Deposition on the Microstructure of Inconel 718 via In Situ Thermal Monitoring Materials additive manufacturing laser engineered net shaping thermal monitoring quality control microstructure melt pool |
| title | Determining the Effects of Inter-Layer Time Interval in Powder-Fed Laser-Directed Energy Deposition on the Microstructure of Inconel 718 via In Situ Thermal Monitoring |
| title_full | Determining the Effects of Inter-Layer Time Interval in Powder-Fed Laser-Directed Energy Deposition on the Microstructure of Inconel 718 via In Situ Thermal Monitoring |
| title_fullStr | Determining the Effects of Inter-Layer Time Interval in Powder-Fed Laser-Directed Energy Deposition on the Microstructure of Inconel 718 via In Situ Thermal Monitoring |
| title_full_unstemmed | Determining the Effects of Inter-Layer Time Interval in Powder-Fed Laser-Directed Energy Deposition on the Microstructure of Inconel 718 via In Situ Thermal Monitoring |
| title_short | Determining the Effects of Inter-Layer Time Interval in Powder-Fed Laser-Directed Energy Deposition on the Microstructure of Inconel 718 via In Situ Thermal Monitoring |
| title_sort | determining the effects of inter layer time interval in powder fed laser directed energy deposition on the microstructure of inconel 718 via in situ thermal monitoring |
| topic | additive manufacturing laser engineered net shaping thermal monitoring quality control microstructure melt pool |
| url | https://www.mdpi.com/1996-1944/17/3/538 |
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