In recent years,a new class of metallic materials featuring heterogeneous structures has emerged.These materials consist of distinct soft and hard domains with significant differences in mechanical properties,allowing...In recent years,a new class of metallic materials featuring heterogeneous structures has emerged.These materials consist of distinct soft and hard domains with significant differences in mechanical properties,allowing them to maintain high strength while offering superior ductility.Magnesium(Mg)alloys,renowned for their low density,high specific strength,exceptional vibration damping,and electromagnetic shielding properties,exhibit tremendous potential as lightweight and functional materials.Despite their advantageous properties,high-strength Mg alloys often suffer from limited ductility.However,the emergence of heterogeneous materials provides a fresh perspective for the development of Mg alloys with both high strength and ductility.This article provided a fundamental overview of heterostructured materials and systematically reviewed the recent research progress in the design of Mg alloys with strength-ductility balance based on heterostructure principles.The review encompassed various aspects,including preparation methods,formation mechanisms of diverse heterostructures,and mechanical properties,both within domestic and international contexts.On this basis,the article discussed the challenges encountered in the design and fabrication of heterostructured Mg alloys,as well as the urgent issues that require attention and resolution in the future.展开更多
The microstructures and tension properties of Fe_(50)Mn_(20)Cr_(20)Ni_(10) medium entropy alloy(MEA)were investigated,which was produced by vacuum induction melting and subsequently was homogenized at 1200 C for 6 h.M...The microstructures and tension properties of Fe_(50)Mn_(20)Cr_(20)Ni_(10) medium entropy alloy(MEA)were investigated,which was produced by vacuum induction melting and subsequently was homogenized at 1200 C for 6 h.Microstructure characterization shows the single-phase solid solution with face-centered cubic structure by means of transmission electron microscopy and scanning electron microscopy combined with energy disperse spectroscopy.Our Fe-MEA has an ultimate tensile strength of 550±10 MPa and a high strain hardening exponent,n,of 0.41 as well as a higher ductility(60%)than those of CrMnFeCoNi alloy.The single-phase solid solution deforms plastically via dislocations and twins.Twin boundaries associated with deformation twinning impede dislocation motion,enhancing the strain hardening capacity.This article focuses on the insights into the concept of Fe-MEAs and provides a potential direction for the future development of high entropy alloys and MEAs.展开更多
We develop a new ultrastrong medium Mn steel with a density reduced to 7.39 g cm^(-3).It has a novel tri-phase microstructure comprising a hierarchical martensitic matrix(α’),dispersed ultra-fine-retained austenite ...We develop a new ultrastrong medium Mn steel with a density reduced to 7.39 g cm^(-3).It has a novel tri-phase microstructure comprising a hierarchical martensitic matrix(α’),dispersed ultra-fine-retained austenite grains(γ),and both compressed and{200}orientedδ-ferrite lamellas,the latter’s formation is due to the alloying of high Al and Si contents for reducing density.As a result,both ultrahigh ultimate tensile strength of 2.1 GPa and good ductility of 16%are achieved after an extraordinary plastic strain hardening increment of about 1.4 GPa.The in-situ synchrotron-based high-energy(HE)X-ray diffraction(XRD)examinations during the tensile deformation revealed that the initial presence of residual com-pressive stress inδ-ferrite could increase the stress required to initiate the plastic tensile deformation of the specimen,leading to the isolatedδ-ferrite lamellas mostly deformed elastically to coordinate the plastic deformation of the martensitic matrix during yielding.During the plastic deformation,the gradual release of residual compressive stress inδandα’,the dislocation multiplication in all the three phases and the successiveγ-to-α’transformation all contribute to such a prominent work hardening increment.This study facilitates the development of novel strategies for fabricating ultrastrong but light steels.展开更多
基金supported by Yunnan Fundamental Research Projects(No.202201BE070001-014)Doctoral Scientific Research Foundation of Hubei University of Automotive Technology(No.BK202336)+4 种基金National Natural Science Foundation of China(No.52071035)Program for Science and Technology Innovation Team in Colleges of Hubei Province(No.T2021012)Outstanding Young Scientific&Technological Innovation Team Plan of Colleges and Universities in Hubei Province(No.T201518 and No.T201811)Major Science and Technology Project of Hubei Province(No.2022AAA001)Key R&D Project of Hubei Province(No.2021BAB019)。
文摘In recent years,a new class of metallic materials featuring heterogeneous structures has emerged.These materials consist of distinct soft and hard domains with significant differences in mechanical properties,allowing them to maintain high strength while offering superior ductility.Magnesium(Mg)alloys,renowned for their low density,high specific strength,exceptional vibration damping,and electromagnetic shielding properties,exhibit tremendous potential as lightweight and functional materials.Despite their advantageous properties,high-strength Mg alloys often suffer from limited ductility.However,the emergence of heterogeneous materials provides a fresh perspective for the development of Mg alloys with both high strength and ductility.This article provided a fundamental overview of heterostructured materials and systematically reviewed the recent research progress in the design of Mg alloys with strength-ductility balance based on heterostructure principles.The review encompassed various aspects,including preparation methods,formation mechanisms of diverse heterostructures,and mechanical properties,both within domestic and international contexts.On this basis,the article discussed the challenges encountered in the design and fabrication of heterostructured Mg alloys,as well as the urgent issues that require attention and resolution in the future.
基金the Natural Science Foundation of Shanxi Province,China(Nos.201901DI11105 and 201901D111114)Transformation of Scientific and Technological Achievements Programs of Higher Education Institutions in Shanxi(2019)+2 种基金State Key Lab of Advanced Metals and Materials of China(Grant No.2020-Z09)the opening project of the State Key Laboratory of Explosion Science and Technology(Beijing Institute of Technology)the opening project number is KFJJ20-13M.
文摘The microstructures and tension properties of Fe_(50)Mn_(20)Cr_(20)Ni_(10) medium entropy alloy(MEA)were investigated,which was produced by vacuum induction melting and subsequently was homogenized at 1200 C for 6 h.Microstructure characterization shows the single-phase solid solution with face-centered cubic structure by means of transmission electron microscopy and scanning electron microscopy combined with energy disperse spectroscopy.Our Fe-MEA has an ultimate tensile strength of 550±10 MPa and a high strain hardening exponent,n,of 0.41 as well as a higher ductility(60%)than those of CrMnFeCoNi alloy.The single-phase solid solution deforms plastically via dislocations and twins.Twin boundaries associated with deformation twinning impede dislocation motion,enhancing the strain hardening capacity.This article focuses on the insights into the concept of Fe-MEAs and provides a potential direction for the future development of high entropy alloys and MEAs.
基金Haiwen Luo and Bin Hu acknowledge financial support from the National Natural Science Foundation of China(Nos.51831002,51904028 and 52233018)Fundamental Research Funds for the Central Universities(No.06500151)The present work is re-lated to awarded patents(No.201910244716.9 in China and No.US 10793932 in the USA).
文摘We develop a new ultrastrong medium Mn steel with a density reduced to 7.39 g cm^(-3).It has a novel tri-phase microstructure comprising a hierarchical martensitic matrix(α’),dispersed ultra-fine-retained austenite grains(γ),and both compressed and{200}orientedδ-ferrite lamellas,the latter’s formation is due to the alloying of high Al and Si contents for reducing density.As a result,both ultrahigh ultimate tensile strength of 2.1 GPa and good ductility of 16%are achieved after an extraordinary plastic strain hardening increment of about 1.4 GPa.The in-situ synchrotron-based high-energy(HE)X-ray diffraction(XRD)examinations during the tensile deformation revealed that the initial presence of residual com-pressive stress inδ-ferrite could increase the stress required to initiate the plastic tensile deformation of the specimen,leading to the isolatedδ-ferrite lamellas mostly deformed elastically to coordinate the plastic deformation of the martensitic matrix during yielding.During the plastic deformation,the gradual release of residual compressive stress inδandα’,the dislocation multiplication in all the three phases and the successiveγ-to-α’transformation all contribute to such a prominent work hardening increment.This study facilitates the development of novel strategies for fabricating ultrastrong but light steels.
