Synergistically enhanced cryogenic strength and ductility in 304L stainless steel made by directed energy deposition additive manufacturing
We leverage the rapid cooling rates and thermal cycling inherent to laser directed energy deposition (DED) additive manufacturing (AM), to synthesize 304L stainless steel with bimodal grain size distribution and intragranular cellular dislocation structures. We find that regardless of the printing s...
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| Format: | Article |
| Language: | English |
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Elsevier
2025-05-01
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| Series: | Materials & Design |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S0264127525003260 |
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| author | Yen-Ting Chang Andrew Hattoon Enriquez Yuheng Nie Didun Oladeji Marie A. Charpagne |
| author_facet | Yen-Ting Chang Andrew Hattoon Enriquez Yuheng Nie Didun Oladeji Marie A. Charpagne |
| author_sort | Yen-Ting Chang |
| collection | DOAJ |
| description | We leverage the rapid cooling rates and thermal cycling inherent to laser directed energy deposition (DED) additive manufacturing (AM), to synthesize 304L stainless steel with bimodal grain size distribution and intragranular cellular dislocation structures. We find that regardless of the printing strategy, DED AM 304L exhibits synergistically enhanced strength and ductility from room temperature down to cryogenic temperature (77 K); that surpasses the mechanical performance of 304L synthesized via conventional processes. We follow the evolution of statistically representative microstructure regions using electron microscopy during quasi in-situ tensile tests interrupted at different strain levels and reveal the deformation mechanisms responsible for this behavior. First, cellular dislocation structures act as emission sites for Shockley partials, leading to a dense network of deformation twins at room temperature, and martensite at 77 K. Second, martensite formation takes place at different rates in the bimodal microstructure, leading to sustained work-hardening. Using the Olsen-Cohen model, we reveal a higher formation rate of α′ martensite in comparison with previous literature on wrought 304L; as well as distinct transformation rates between the large and small grains in our DED 304L. These findings highlight the potential of DED AM as a promising synthesis method for stainless steels in cryogenic applications. |
| format | Article |
| id | doaj-art-7dcfd1d2e7df4574906490f3fa376e43 |
| institution | OA Journals |
| issn | 0264-1275 |
| language | English |
| publishDate | 2025-05-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Materials & Design |
| spelling | doaj-art-7dcfd1d2e7df4574906490f3fa376e432025-08-20T02:38:30ZengElsevierMaterials & Design0264-12752025-05-0125311390610.1016/j.matdes.2025.113906Synergistically enhanced cryogenic strength and ductility in 304L stainless steel made by directed energy deposition additive manufacturingYen-Ting Chang0Andrew Hattoon Enriquez1Yuheng Nie2Didun Oladeji3Marie A. Charpagne4Department of Materials Science and Engineering, the Grainger College of Engineering, University of Illinois Urbana-Champaign, USADepartment of Materials Science and Engineering, the Grainger College of Engineering, University of Illinois Urbana-Champaign, USADepartment of Materials Science and Engineering, the Grainger College of Engineering, University of Illinois Urbana-Champaign, USADepartment of Materials Science and Engineering, the Grainger College of Engineering, University of Illinois Urbana-Champaign, USACorresponding author.; Department of Materials Science and Engineering, the Grainger College of Engineering, University of Illinois Urbana-Champaign, USAWe leverage the rapid cooling rates and thermal cycling inherent to laser directed energy deposition (DED) additive manufacturing (AM), to synthesize 304L stainless steel with bimodal grain size distribution and intragranular cellular dislocation structures. We find that regardless of the printing strategy, DED AM 304L exhibits synergistically enhanced strength and ductility from room temperature down to cryogenic temperature (77 K); that surpasses the mechanical performance of 304L synthesized via conventional processes. We follow the evolution of statistically representative microstructure regions using electron microscopy during quasi in-situ tensile tests interrupted at different strain levels and reveal the deformation mechanisms responsible for this behavior. First, cellular dislocation structures act as emission sites for Shockley partials, leading to a dense network of deformation twins at room temperature, and martensite at 77 K. Second, martensite formation takes place at different rates in the bimodal microstructure, leading to sustained work-hardening. Using the Olsen-Cohen model, we reveal a higher formation rate of α′ martensite in comparison with previous literature on wrought 304L; as well as distinct transformation rates between the large and small grains in our DED 304L. These findings highlight the potential of DED AM as a promising synthesis method for stainless steels in cryogenic applications.http://www.sciencedirect.com/science/article/pii/S0264127525003260Additive manufacturingStrain-induced transformationsCryogenic deformationMechanical twinning |
| spellingShingle | Yen-Ting Chang Andrew Hattoon Enriquez Yuheng Nie Didun Oladeji Marie A. Charpagne Synergistically enhanced cryogenic strength and ductility in 304L stainless steel made by directed energy deposition additive manufacturing Materials & Design Additive manufacturing Strain-induced transformations Cryogenic deformation Mechanical twinning |
| title | Synergistically enhanced cryogenic strength and ductility in 304L stainless steel made by directed energy deposition additive manufacturing |
| title_full | Synergistically enhanced cryogenic strength and ductility in 304L stainless steel made by directed energy deposition additive manufacturing |
| title_fullStr | Synergistically enhanced cryogenic strength and ductility in 304L stainless steel made by directed energy deposition additive manufacturing |
| title_full_unstemmed | Synergistically enhanced cryogenic strength and ductility in 304L stainless steel made by directed energy deposition additive manufacturing |
| title_short | Synergistically enhanced cryogenic strength and ductility in 304L stainless steel made by directed energy deposition additive manufacturing |
| title_sort | synergistically enhanced cryogenic strength and ductility in 304l stainless steel made by directed energy deposition additive manufacturing |
| topic | Additive manufacturing Strain-induced transformations Cryogenic deformation Mechanical twinning |
| url | http://www.sciencedirect.com/science/article/pii/S0264127525003260 |
| work_keys_str_mv | AT yentingchang synergisticallyenhancedcryogenicstrengthandductilityin304lstainlesssteelmadebydirectedenergydepositionadditivemanufacturing AT andrewhattoonenriquez synergisticallyenhancedcryogenicstrengthandductilityin304lstainlesssteelmadebydirectedenergydepositionadditivemanufacturing AT yuhengnie synergisticallyenhancedcryogenicstrengthandductilityin304lstainlesssteelmadebydirectedenergydepositionadditivemanufacturing AT didunoladeji synergisticallyenhancedcryogenicstrengthandductilityin304lstainlesssteelmadebydirectedenergydepositionadditivemanufacturing AT marieacharpagne synergisticallyenhancedcryogenicstrengthandductilityin304lstainlesssteelmadebydirectedenergydepositionadditivemanufacturing |