On the stray grains in single-crystal Ni-based superalloy by additive manufacturing: formation mechanism and elimination strategy
Single-crystal nickel-based superalloys are indispensable for aerospace engine turbine blades due to their superior high-temperature performance. Traditional manufacturing methods are complex and costly, with additional expenses from scrapping damaged blades. Directed energy deposition (DED) offers...
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| Format: | Article |
| Language: | English |
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Elsevier
2025-05-01
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| Series: | Journal of Materials Research and Technology |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2238785425011470 |
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| author | Zheyu Yang Xiaochen Li Jiaqiang Chang Zhaoxuan Wu Yanhong Yang Zhenbo Zhang |
| author_facet | Zheyu Yang Xiaochen Li Jiaqiang Chang Zhaoxuan Wu Yanhong Yang Zhenbo Zhang |
| author_sort | Zheyu Yang |
| collection | DOAJ |
| description | Single-crystal nickel-based superalloys are indispensable for aerospace engine turbine blades due to their superior high-temperature performance. Traditional manufacturing methods are complex and costly, with additional expenses from scrapping damaged blades. Directed energy deposition (DED) offers an effective solution for blade repairs and a promising approach for direct blade production. This study is dedicated to understanding how processing parameters affect the formation of stray grains (SGs) and cracks in flat-top laser DED, and proposing feasible strategies to eliminate SGs and cracks. Results show that surface SGs are mainly due to the excessive powder feeding, and the SGs formed in the sample interior near to the substrate result from the occurrence of constitutional undercooling during the deposition of the first track. Unidirectional laser scanning can also trigger the nucleation and growth of SGs, but this can be significantly reduced through bidirectional laser scanning. For DED multi-track bulk samples, the hatch spacing is found to be the determining factor for the formation of SGs. Cracks can be completely eliminated if formation of high angle grain boundaries are inhibited during DED. Finally, crack-free multi-track samples were achieved using the optimized process parameters, demonstrating the feasibility of proposed approach in enhancing the integrity of additively manufactured single-crystal nickel-based superalloys. |
| format | Article |
| id | doaj-art-60e65ab419f24f2b976aa6a26807fc91 |
| institution | DOAJ |
| issn | 2238-7854 |
| language | English |
| publishDate | 2025-05-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Materials Research and Technology |
| spelling | doaj-art-60e65ab419f24f2b976aa6a26807fc912025-08-20T02:57:05ZengElsevierJournal of Materials Research and Technology2238-78542025-05-01367125713410.1016/j.jmrt.2025.04.326On the stray grains in single-crystal Ni-based superalloy by additive manufacturing: formation mechanism and elimination strategyZheyu Yang0Xiaochen Li1Jiaqiang Chang2Zhaoxuan Wu3Yanhong Yang4Zhenbo Zhang5Center for Adaptive System Engineering, ShanghaiTech University, Shanghai, 201210, ChinaCenter for Adaptive System Engineering, ShanghaiTech University, Shanghai, 201210, ChinaCenter for Adaptive System Engineering, ShanghaiTech University, Shanghai, 201210, ChinaCenter for Adaptive System Engineering, ShanghaiTech University, Shanghai, 201210, ChinaInstitute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, China; Corresponding author.Center for Adaptive System Engineering, ShanghaiTech University, Shanghai, 201210, China; Corresponding author.Single-crystal nickel-based superalloys are indispensable for aerospace engine turbine blades due to their superior high-temperature performance. Traditional manufacturing methods are complex and costly, with additional expenses from scrapping damaged blades. Directed energy deposition (DED) offers an effective solution for blade repairs and a promising approach for direct blade production. This study is dedicated to understanding how processing parameters affect the formation of stray grains (SGs) and cracks in flat-top laser DED, and proposing feasible strategies to eliminate SGs and cracks. Results show that surface SGs are mainly due to the excessive powder feeding, and the SGs formed in the sample interior near to the substrate result from the occurrence of constitutional undercooling during the deposition of the first track. Unidirectional laser scanning can also trigger the nucleation and growth of SGs, but this can be significantly reduced through bidirectional laser scanning. For DED multi-track bulk samples, the hatch spacing is found to be the determining factor for the formation of SGs. Cracks can be completely eliminated if formation of high angle grain boundaries are inhibited during DED. Finally, crack-free multi-track samples were achieved using the optimized process parameters, demonstrating the feasibility of proposed approach in enhancing the integrity of additively manufactured single-crystal nickel-based superalloys.http://www.sciencedirect.com/science/article/pii/S2238785425011470Single-crystal Ni-based superalloyDirect energy depositionStray grainScanning strategyFlat-top laser |
| spellingShingle | Zheyu Yang Xiaochen Li Jiaqiang Chang Zhaoxuan Wu Yanhong Yang Zhenbo Zhang On the stray grains in single-crystal Ni-based superalloy by additive manufacturing: formation mechanism and elimination strategy Journal of Materials Research and Technology Single-crystal Ni-based superalloy Direct energy deposition Stray grain Scanning strategy Flat-top laser |
| title | On the stray grains in single-crystal Ni-based superalloy by additive manufacturing: formation mechanism and elimination strategy |
| title_full | On the stray grains in single-crystal Ni-based superalloy by additive manufacturing: formation mechanism and elimination strategy |
| title_fullStr | On the stray grains in single-crystal Ni-based superalloy by additive manufacturing: formation mechanism and elimination strategy |
| title_full_unstemmed | On the stray grains in single-crystal Ni-based superalloy by additive manufacturing: formation mechanism and elimination strategy |
| title_short | On the stray grains in single-crystal Ni-based superalloy by additive manufacturing: formation mechanism and elimination strategy |
| title_sort | on the stray grains in single crystal ni based superalloy by additive manufacturing formation mechanism and elimination strategy |
| topic | Single-crystal Ni-based superalloy Direct energy deposition Stray grain Scanning strategy Flat-top laser |
| url | http://www.sciencedirect.com/science/article/pii/S2238785425011470 |
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