首页|Achieving strength-ductility synergy in novel paramagnetic Fe-based medium-entropy alloys through deep cryogenic deformation

Achieving strength-ductility synergy in novel paramagnetic Fe-based medium-entropy alloys through deep cryogenic deformation

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Cryogenic pre-deformation treatment has been widely used to effectively improve the comprehensive mechanical properties of steels and novel metals.However,the dislocation evolution and phase transformation induced by different degrees of deep cryogenic deformation are not yet fully elucidated.In this study,the effects of multiple cryogenic pre-treatments on the mechanical properties and deformation mechanisms of a paramagnetic Fe63.3Mn14-Si9.1Cr9.8C3.8 medium-entropy alloy(MEA)were investi-gated,leading to the discovery of a pretreated MEA that exhibits exceptional mechanical properties,including a fracture strength of 3.0 GPa,plastic strain of 26.1％and work-hardening index of 0.57.In addition,X-ray diffrac-tion(XRD)and transmission electron microscopy(TEM)analyses revealed that multiple cryogenic pre-deformation treatments significantly increased the dislocation density of the MEA(from 9 × 1015 to 4 × 1016 m-2 after three pre-treatments),along with a transition in the dislocation type from predominantly edge dislocations to mixed disloca-tions(including screw-and edge-type dislocations).Nota-bly,this pretreated MEA retained its paramagnetic properties(µr＜1.0200)even after fracture.Thermody-namic calculations showed that cryogenic pretreatment can significantly reduce the stacking fault energy of the MEA by a factor of approximately four(i.e.,from 9.7 to 2.6 mJ·m-2),thereby activating the synergistic effects of transformation-induced plasticity,twinning-induced plas-ticity and dislocation strengthening mechanisms.These synergistic effects lead to simultaneous strength and duc-tility enhancement of the MEA.

Deep cryogenic transformationIron-based medium-entropy alloysDislocation evolutionPhase transformationStacking fault energy

Hu-Wen Ma、Yan-Chun Zhao、Li Feng、Tian-Zeng Liu、Zhi-Qi Yu、Bo Jin、Wang-Chun Duan、Peter K.Liaw、Dong Ma

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State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals,Lanzhou University of Technology,Lanzhou 730050,China

State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals,Lanzhou University of Technology,Lanzhou 730050,China

Wenzhou Pump and Valve Engineering Research Institute,Lanzhou University of Technology,Wenzhou 325105,China

State Key Laboratory of Advanced Processing and Recycling of Non-Ferrous Metals,Lanzhou University of Technology,Lanzhou 730050,China

Iron and Steel Research Institute,Jiuquan Iron and Steel Corporation,Jiayuguan 735100,China

Lanzhou Resources and Environment Voc-Tech University,Lanzhou 730123,China

Department of Materials Science and Engineering,The University of Tennessee,Knoxville,TN 37996-2200,USA

Neutron Science Center,Songshan Lake Materials Laboratory,Dongguan 523808,China

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National Natural Science Foundation of ChinaNational Natural Science Foundation of ChinaZhejiang Provincial Natural Science Foundation of ChinaScience and Technology Program Project of Gansu ProvinceScience and Technology Program Project of Gansu ProvinceLanzhou Youth Science and Technology Talent Innovation Project

5206102752130108LY23E01000222YF7GA15522ZD6GA0082023-QN-91

2024

10.1007/s12598-024-02865-9

稀有金属(英文版)
中国有色金属学会

稀有金属(英文版)

CSTPCDEI
影响因子：0.801
ISSN：1001-0521
年,卷(期)：2024.43(9)
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