Cracks suppression strategies for CoCrNi medium entropy alloy fabricated by laser directed energy deposition
Laser-directed energy deposition (l-DED) additive manufacturing of the CoCrNi medium entropy alloy is prone to cracking, especially with high laser heat input. Electron backscatter diffraction analysis showed crack formation and stress concentration at the high-angle grain boundaries. In addition, e...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2023-02-01
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| Series: | Materials & Design |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0264127522012023 |
| _version_ | 1811158462914101248 |
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| author | Xiaolin Bi Ruifeng Li Taotao Li Xiancheng Zhang Jiangbo Cheng Yingtao Tian |
| author_facet | Xiaolin Bi Ruifeng Li Taotao Li Xiancheng Zhang Jiangbo Cheng Yingtao Tian |
| author_sort | Xiaolin Bi |
| collection | DOAJ |
| description | Laser-directed energy deposition (l-DED) additive manufacturing of the CoCrNi medium entropy alloy is prone to cracking, especially with high laser heat input. Electron backscatter diffraction analysis showed crack formation and stress concentration at the high-angle grain boundaries. In addition, element content test results exhibited a higher oxygen content in the additive parts with high laser heat input. Electron probe X-ray microanalysis indicated that the oxygen was distributed uniformly in the additive parts. Corresponding molecular dynamics simulation results revealed that an increase in oxygen content led to a decrease in the tensile strength of the additive parts. Two methods of argon-filled environment l-DED experiments and low-oxygen CoCrNi feeding power (argon gas atomization) were used. Results showed that the number and size of cracks were significantly reduced in the additive parts obtained by a high heat input process when the l-DED was conducted in an argon-filled atmosphere and when powders with lower oxygen content were used. For the crack-free additive parts, the ultimate tensile strengths reached 625 MPa with high laser heat input. Three crack suppression strategies could be proposed from this study, namely, reducing the heat input, performing additive experiments under argon-filled environment, and decreasing the oxygen content of the powder. |
| first_indexed | 2024-04-10T05:25:06Z |
| format | Article |
| id | doaj.art-b433b62d4c5f4180a8f5801f7b9e3cc0 |
| institution | Directory Open Access Journal |
| issn | 0264-1275 |
| language | English |
| last_indexed | 2024-04-10T05:25:06Z |
| publishDate | 2023-02-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Materials & Design |
| spelling | doaj.art-b433b62d4c5f4180a8f5801f7b9e3cc02023-03-08T04:13:23ZengElsevierMaterials & Design0264-12752023-02-01226111579Cracks suppression strategies for CoCrNi medium entropy alloy fabricated by laser directed energy depositionXiaolin Bi0Ruifeng Li1Taotao Li2Xiancheng Zhang3Jiangbo Cheng4Yingtao Tian5School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang 212100, ChinaSchool of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang 212100, China; Corresponding author.School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang 212100, ChinaKey Laboratory of Pressure Systems and Safety, Ministry of Education, East China University of Science and Technology, Shanghai 200237, ChinaCollege of Mechanics and Materials, Hohai University, Nanjing, Jiangsu 211100, ChinaDepartment of Engineering, Lancaster University, Lancaster LA1 4YW, UKLaser-directed energy deposition (l-DED) additive manufacturing of the CoCrNi medium entropy alloy is prone to cracking, especially with high laser heat input. Electron backscatter diffraction analysis showed crack formation and stress concentration at the high-angle grain boundaries. In addition, element content test results exhibited a higher oxygen content in the additive parts with high laser heat input. Electron probe X-ray microanalysis indicated that the oxygen was distributed uniformly in the additive parts. Corresponding molecular dynamics simulation results revealed that an increase in oxygen content led to a decrease in the tensile strength of the additive parts. Two methods of argon-filled environment l-DED experiments and low-oxygen CoCrNi feeding power (argon gas atomization) were used. Results showed that the number and size of cracks were significantly reduced in the additive parts obtained by a high heat input process when the l-DED was conducted in an argon-filled atmosphere and when powders with lower oxygen content were used. For the crack-free additive parts, the ultimate tensile strengths reached 625 MPa with high laser heat input. Three crack suppression strategies could be proposed from this study, namely, reducing the heat input, performing additive experiments under argon-filled environment, and decreasing the oxygen content of the powder.http://www.sciencedirect.com/science/article/pii/S0264127522012023CoCrNi medium entropy alloyLaser-directed energy depositionOxygen contentHigh-angle grain boundary stressCrack suppression |
| spellingShingle | Xiaolin Bi Ruifeng Li Taotao Li Xiancheng Zhang Jiangbo Cheng Yingtao Tian Cracks suppression strategies for CoCrNi medium entropy alloy fabricated by laser directed energy deposition Materials & Design CoCrNi medium entropy alloy Laser-directed energy deposition Oxygen content High-angle grain boundary stress Crack suppression |
| title | Cracks suppression strategies for CoCrNi medium entropy alloy fabricated by laser directed energy deposition |
| title_full | Cracks suppression strategies for CoCrNi medium entropy alloy fabricated by laser directed energy deposition |
| title_fullStr | Cracks suppression strategies for CoCrNi medium entropy alloy fabricated by laser directed energy deposition |
| title_full_unstemmed | Cracks suppression strategies for CoCrNi medium entropy alloy fabricated by laser directed energy deposition |
| title_short | Cracks suppression strategies for CoCrNi medium entropy alloy fabricated by laser directed energy deposition |
| title_sort | cracks suppression strategies for cocrni medium entropy alloy fabricated by laser directed energy deposition |
| topic | CoCrNi medium entropy alloy Laser-directed energy deposition Oxygen content High-angle grain boundary stress Crack suppression |
| url | http://www.sciencedirect.com/science/article/pii/S0264127522012023 |
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