Microstructural characterization and mechanical properties of additively manufactured 21-6-9 stainless steel for aerospace applications
The alloy 21-6-9 is a nitrogen-strengthened austenitic stainless steel often used in aerospace applications due to its high strength, good fabrication properties, and toughness at cryogenic temperatures. However, minimal research has been conducted on alloy 21-6-9 using the additive manufacturing pr...
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| Format: | Article |
| Language: | English |
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Elsevier
2023-07-01
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| Series: | Journal of Materials Research and Technology |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2238785423012954 |
| _version_ | 1797745247152766976 |
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| author | Pragya Mishra Pia Åkerfeldt Fredrik Svahn Erik Nilsson Farnoosh Forouzan Marta-Lena Antti |
| author_facet | Pragya Mishra Pia Åkerfeldt Fredrik Svahn Erik Nilsson Farnoosh Forouzan Marta-Lena Antti |
| author_sort | Pragya Mishra |
| collection | DOAJ |
| description | The alloy 21-6-9 is a nitrogen-strengthened austenitic stainless steel often used in aerospace applications due to its high strength, good fabrication properties, and toughness at cryogenic temperatures. However, minimal research has been conducted on alloy 21-6-9 using the additive manufacturing process laser powder-bed fusion (L-PBF). The L-PBF technique has been seen as a key to reducing production time and avoiding costly machining. Therefore, there is an interest in investigating L-PBF-processed 21-6-9 to determine the effects of L-PBF on properties at elevated and cryogenic temperatures. In this study, prior to tensile testing the alloy 21-6-9 underwent heat treatments that simulated aerospace applications and the alloy was analyzed and characterized to evaluate phase stability. The effects of elevated and cryogenic temperatures (77 K) on the tensile behavior and microstructure were investigated using X-ray diffraction (XRD) and electron backscatter diffraction (EBSD). The tensile tests showed that the yield strength and ultimate tensile strength improved, while ductility varied depending on the conditions and test environment. The ultimate tensile strength was approximately 80% higher at 77 K than at room temperature, although the elongation decreased by around 90%, possibly due to the formation of strain-induced martensite. |
| first_indexed | 2024-03-12T15:20:39Z |
| format | Article |
| id | doaj.art-451fa39ffbad4dfe983e6804857df4b4 |
| institution | Directory Open Access Journal |
| issn | 2238-7854 |
| language | English |
| last_indexed | 2024-03-12T15:20:39Z |
| publishDate | 2023-07-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Materials Research and Technology |
| spelling | doaj.art-451fa39ffbad4dfe983e6804857df4b42023-08-11T05:33:22ZengElsevierJournal of Materials Research and Technology2238-78542023-07-012514831494Microstructural characterization and mechanical properties of additively manufactured 21-6-9 stainless steel for aerospace applicationsPragya Mishra0Pia Åkerfeldt1Fredrik Svahn2Erik Nilsson3Farnoosh Forouzan4Marta-Lena Antti5Materials Science, Department of Engineering Sciences and Mathematics, Luleå University of Technology, 97187 Luleå, Sweden; Corresponding author.Materials Science, Department of Engineering Sciences and Mathematics, Luleå University of Technology, 97187 Luleå, SwedenGKN Aerospace Sweden AB, 46130 Trollhättan, SwedenMaterials Science, Department of Engineering Sciences and Mathematics, Luleå University of Technology, 97187 Luleå, SwedenMaterials Science, Department of Engineering Sciences and Mathematics, Luleå University of Technology, 97187 Luleå, Sweden; Höganäs AB, 263 39 Höganäs, SwedenMaterials Science, Department of Engineering Sciences and Mathematics, Luleå University of Technology, 97187 Luleå, SwedenThe alloy 21-6-9 is a nitrogen-strengthened austenitic stainless steel often used in aerospace applications due to its high strength, good fabrication properties, and toughness at cryogenic temperatures. However, minimal research has been conducted on alloy 21-6-9 using the additive manufacturing process laser powder-bed fusion (L-PBF). The L-PBF technique has been seen as a key to reducing production time and avoiding costly machining. Therefore, there is an interest in investigating L-PBF-processed 21-6-9 to determine the effects of L-PBF on properties at elevated and cryogenic temperatures. In this study, prior to tensile testing the alloy 21-6-9 underwent heat treatments that simulated aerospace applications and the alloy was analyzed and characterized to evaluate phase stability. The effects of elevated and cryogenic temperatures (77 K) on the tensile behavior and microstructure were investigated using X-ray diffraction (XRD) and electron backscatter diffraction (EBSD). The tensile tests showed that the yield strength and ultimate tensile strength improved, while ductility varied depending on the conditions and test environment. The ultimate tensile strength was approximately 80% higher at 77 K than at room temperature, although the elongation decreased by around 90%, possibly due to the formation of strain-induced martensite.http://www.sciencedirect.com/science/article/pii/S2238785423012954L-PBF21-6-9 stainless steelElevated temperatureCryogenic temperatureMicrostructural characterizationMechanical properties |
| spellingShingle | Pragya Mishra Pia Åkerfeldt Fredrik Svahn Erik Nilsson Farnoosh Forouzan Marta-Lena Antti Microstructural characterization and mechanical properties of additively manufactured 21-6-9 stainless steel for aerospace applications Journal of Materials Research and Technology L-PBF 21-6-9 stainless steel Elevated temperature Cryogenic temperature Microstructural characterization Mechanical properties |
| title | Microstructural characterization and mechanical properties of additively manufactured 21-6-9 stainless steel for aerospace applications |
| title_full | Microstructural characterization and mechanical properties of additively manufactured 21-6-9 stainless steel for aerospace applications |
| title_fullStr | Microstructural characterization and mechanical properties of additively manufactured 21-6-9 stainless steel for aerospace applications |
| title_full_unstemmed | Microstructural characterization and mechanical properties of additively manufactured 21-6-9 stainless steel for aerospace applications |
| title_short | Microstructural characterization and mechanical properties of additively manufactured 21-6-9 stainless steel for aerospace applications |
| title_sort | microstructural characterization and mechanical properties of additively manufactured 21 6 9 stainless steel for aerospace applications |
| topic | L-PBF 21-6-9 stainless steel Elevated temperature Cryogenic temperature Microstructural characterization Mechanical properties |
| url | http://www.sciencedirect.com/science/article/pii/S2238785423012954 |
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