Phase reversion mediated the dual heterogeneity of grain size and dislocation density in an equiatomic CrCoNi medium-entropy alloy
An ultra-high strain rate (104 s−1) dynamic plastic deformation treatment at liquid nitrogen temperature (LNT-DPD) followed by annealing is carried out to obtain dual heterogeneity of grain size and dislocation density in an equiatomic CrCoNi medium entropy alloy (MEA). Such extreme loading conditio...
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2024-11-01
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| Series: | Journal of Materials Research and Technology |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2238785424020842 |
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| author | Kun Jiang Jianguo Li Xi Chen Bin Gan Qingbo Dou Tao Suo |
| author_facet | Kun Jiang Jianguo Li Xi Chen Bin Gan Qingbo Dou Tao Suo |
| author_sort | Kun Jiang |
| collection | DOAJ |
| description | An ultra-high strain rate (104 s−1) dynamic plastic deformation treatment at liquid nitrogen temperature (LNT-DPD) followed by annealing is carried out to obtain dual heterogeneity of grain size and dislocation density in an equiatomic CrCoNi medium entropy alloy (MEA). Such extreme loading conditions resulted in extensive phase transformation in this MEA. Subsequent annealing at 650 °C for 1 h further induced reverse phase transformation and partial recrystallization, forming a complex heterogeneous microstructure characterized by nested trimodal grain sizes and partitioned dislocation density. A superior yield strength of ∼800 MPa and a good ductility of ∼40% were simultaneously achieved in this heterogeneous alloy. In order to reveal the effects of grain size and dislocation density distributions on the mechanical property improvements, the underlying deformation mechanisms were systematically discussed. High density of geometrically necessary dislocations (GNDs) would be induced in complex heterogeneous structures during tensile deformation due to strain gradients or partitioning between different regions, which would lead to additional strengthening and work hardening. These results provide a novel approach to overcome the strength-ductility trade-off dilemma for FCC-structured MEAs. |
| format | Article |
| id | doaj-art-70cc5d74676b4e61bc0b68bef632e140 |
| institution | OA Journals |
| issn | 2238-7854 |
| language | English |
| publishDate | 2024-11-01 |
| publisher | Elsevier |
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| series | Journal of Materials Research and Technology |
| spelling | doaj-art-70cc5d74676b4e61bc0b68bef632e1402025-08-20T02:35:26ZengElsevierJournal of Materials Research and Technology2238-78542024-11-013347147910.1016/j.jmrt.2024.09.080Phase reversion mediated the dual heterogeneity of grain size and dislocation density in an equiatomic CrCoNi medium-entropy alloyKun Jiang0Jianguo Li1Xi Chen2Bin Gan3Qingbo Dou4Tao Suo5School of Aeronautics, Northwestern Polytechnical University, Xi'an, 710072, China; Suzhou Laboratory, Suzhou, 215123, ChinaSchool of Aeronautics, Northwestern Polytechnical University, Xi'an, 710072, China; Institute of Extreme Mechanics, Northwestern Polytechnical University, Xi'an, 710072, China; Shaanxi Key Laboratory of Impact Dynamics and its Engineering Application, Xi'an, 710072, China; Joint International Research Laboratory of Impact Dynamics and its Engineering Application, Xi'an, 710072, China; National Key Laboratory of Strength and Structural Integrity, Xi'an, 710072, China; Corresponding author. School of Aeronautics, Northwestern Polytechnical University, Xi'an, 710072, China.Center for X-mechanics, Zhejiang University, Hangzhou, Zhejiang, 310027, ChinaSuzhou Laboratory, Suzhou, 215123, ChinaSchool of Aeronautics, Northwestern Polytechnical University, Xi'an, 710072, China; Institute of Extreme Mechanics, Northwestern Polytechnical University, Xi'an, 710072, China; Shaanxi Key Laboratory of Impact Dynamics and its Engineering Application, Xi'an, 710072, China; Joint International Research Laboratory of Impact Dynamics and its Engineering Application, Xi'an, 710072, China; National Key Laboratory of Strength and Structural Integrity, Xi'an, 710072, China; Corresponding author. School of Aeronautics, Northwestern Polytechnical University, Xi'an, 710072, China.School of Aeronautics, Northwestern Polytechnical University, Xi'an, 710072, China; Institute of Extreme Mechanics, Northwestern Polytechnical University, Xi'an, 710072, China; Shaanxi Key Laboratory of Impact Dynamics and its Engineering Application, Xi'an, 710072, China; Joint International Research Laboratory of Impact Dynamics and its Engineering Application, Xi'an, 710072, China; National Key Laboratory of Strength and Structural Integrity, Xi'an, 710072, ChinaAn ultra-high strain rate (104 s−1) dynamic plastic deformation treatment at liquid nitrogen temperature (LNT-DPD) followed by annealing is carried out to obtain dual heterogeneity of grain size and dislocation density in an equiatomic CrCoNi medium entropy alloy (MEA). Such extreme loading conditions resulted in extensive phase transformation in this MEA. Subsequent annealing at 650 °C for 1 h further induced reverse phase transformation and partial recrystallization, forming a complex heterogeneous microstructure characterized by nested trimodal grain sizes and partitioned dislocation density. A superior yield strength of ∼800 MPa and a good ductility of ∼40% were simultaneously achieved in this heterogeneous alloy. In order to reveal the effects of grain size and dislocation density distributions on the mechanical property improvements, the underlying deformation mechanisms were systematically discussed. High density of geometrically necessary dislocations (GNDs) would be induced in complex heterogeneous structures during tensile deformation due to strain gradients or partitioning between different regions, which would lead to additional strengthening and work hardening. These results provide a novel approach to overcome the strength-ductility trade-off dilemma for FCC-structured MEAs.http://www.sciencedirect.com/science/article/pii/S2238785424020842Medium entropy alloyPhase transformationHeterogeneous microstructureStrength-ductility synergy |
| spellingShingle | Kun Jiang Jianguo Li Xi Chen Bin Gan Qingbo Dou Tao Suo Phase reversion mediated the dual heterogeneity of grain size and dislocation density in an equiatomic CrCoNi medium-entropy alloy Journal of Materials Research and Technology Medium entropy alloy Phase transformation Heterogeneous microstructure Strength-ductility synergy |
| title | Phase reversion mediated the dual heterogeneity of grain size and dislocation density in an equiatomic CrCoNi medium-entropy alloy |
| title_full | Phase reversion mediated the dual heterogeneity of grain size and dislocation density in an equiatomic CrCoNi medium-entropy alloy |
| title_fullStr | Phase reversion mediated the dual heterogeneity of grain size and dislocation density in an equiatomic CrCoNi medium-entropy alloy |
| title_full_unstemmed | Phase reversion mediated the dual heterogeneity of grain size and dislocation density in an equiatomic CrCoNi medium-entropy alloy |
| title_short | Phase reversion mediated the dual heterogeneity of grain size and dislocation density in an equiatomic CrCoNi medium-entropy alloy |
| title_sort | phase reversion mediated the dual heterogeneity of grain size and dislocation density in an equiatomic crconi medium entropy alloy |
| topic | Medium entropy alloy Phase transformation Heterogeneous microstructure Strength-ductility synergy |
| url | http://www.sciencedirect.com/science/article/pii/S2238785424020842 |
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