Yuntian Zhu
City University of Hong Kong
Composite numberUltimate tensile strengthNanocrystalline materialDeformation (engineering)Transmission electron microscopyDislocationComposite materialNanotechnologyMetallurgyGrain sizeMaterials scienceCondensed matter physicsSevere plastic deformationAlloyGrain boundaryCarbon nanotubeDuctilityCrystal twinningCrystallographyMicrostructure
523Publications
111H-index
32.1kCitations
Publications 498
Newest
#1Xiaolei Wu (CAS: Chinese Academy of Sciences)H-Index: 44
#2Muxin Yang (CAS: Chinese Academy of Sciences)H-Index: 13
Last. Yueguang Wei (PKU: Peking University)
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Gradient structure (GS) possesses a typical trans-scale grain hierarchy with varying internal plastic stability, and the mutual plastic accommodation plays a crucial role in its superior strength-ductility combination. Using the in-situ synchrotron X-ray diffraction (XRD) during tensile loading, we measured lattice strains sequentially from the nanostructured (NS) surface layer to the central coarsegrained (CG) layer to elucidate when and how plastic accommodation occurs and evolves within the G...
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#1Zhufeng He (NU: Northeastern University)H-Index: 2
#2Jia Nan (MOE: Chinese Ministry of Education)H-Index: 2
Last. C.T. Liu (CityU: City University of Hong Kong)H-Index: 106
view all 11 authors...
Abstract: High-entropy alloys (HEAs) have been extensively studied in recent years. However, yield strength of HEAs in which austenite is the dominating phase is usually low, far from satisfying the engineering demands. Improving performance-cost ratio of such alloys will help for their practical structural applications. Here we report a novel strategy to produce ultrastrong, tough, and low-cost HEAs, in which heavy nitrogen-doping (2.6 at.%) was applied to an inexpensive metastable FeMnCoCr HEA...
1 CitationsSource
#1Liwen Zhang (NCSU: North Carolina State University)H-Index: 9
#2Xiaolong Ma (NCSU: North Carolina State University)H-Index: 17
Last. Yuntian Zhu (NCSU: North Carolina State University)H-Index: 111
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We investigated the microstructures of carbon nanotube (CNT) films and the effect of CNT length on their mechanical performance. 230 μm-, 300 μm-, and 360 μm-long CNTs were grown and used to fabricate CNT films by a winding process. Opposite from the length effect on CNT fibers, it has been found that the mechanical properties of the CNT films decrease with increasing CNT length. Without fiber twisting, short CNTs tend to bundle together tightly by themselves in the film structure, resulting in ...
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#1Xiaolei Wu (CAS: Chinese Academy of Sciences)H-Index: 1
#1Xiaolei Wu (CAS: Chinese Academy of Sciences)H-Index: 44
Last. Yuntian Zhu (CityU: City University of Hong Kong)H-Index: 1
view all 2 authors...
Heterostructured (HS) materials are a novel class of materials with mechanical properties that are superior over their conventional homogeneous counterparts. They are composed of HS zones with a dramatic difference in mechanical behaviors, which produces a synergistic effect on mechanical properties that are above the prediction by the rule-of-mixtures. Among all heterostructures, the two most studied are grain-size gradient structure and heterolamellar structure. These two heterostructures prod...
1 CitationsSource
#1Kang Wei (Nanjing University of Science and Technology)H-Index: 9
#1Kang Wei (Nanjing University of Science and Technology)H-Index: 4
Last. Yuntian Zhu (Nanjing University of Science and Technology)H-Index: 1
view all 9 authors...
Abstract Grain refinement can significantly enhance the strength of metallic materials, but usually at the sacrifice of ductility. Here we report that refinement of magnesium grains can not only improve its strength, but also its ductility, due to the activation of more slip systems. It is found that pure Mg with coarse grain size ( d ¯ =125 μm) has a low ductility and uniform elongation (5.3%), due to the limited basal slip systems. In contrast, fine-grained Mg ( d ¯ =5.5 μm) exhibits enhanced ...
2 CitationsSource
#1Lirong Xiao (Nanjing University of Science and Technology)H-Index: 12
#2Xuefei Chen (CAS: Chinese Academy of Sciences)H-Index: 7
Last. Yuntian Zhu (Nanjing University of Science and Technology)H-Index: 111
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Abstract Interfacial segregation has been reported to play a critical role in the thermal-mechanical stability of nanocrystalline Mg alloys. Here we report Ag-segregation-assisted formation of nanocrystalline Mg-Ag alloy with high proportion of sub-grain boundaries during conventional rolling. The segregation structure is determined by dislocation configurations and subsequent strain field and misorientation of the sub-grain boundary. It indicates that the alloying elements, which induce disloca...
3 CitationsSource
#1Jinfeng Nie (Nanjing University of Science and Technology)H-Index: 16
#2Yanfang Liu (Nanjing University of Science and Technology)H-Index: 4
Last. Yonghao Zhao (Nanjing University of Science and Technology)H-Index: 53
view all 10 authors...
Abstract An aluminum matrix composite (AMC) containing ~5% TiB2/TiC particles is processed by high-pressure torsion. The microstructures and mechanical properties of the composites are analyzed in detail. The processed AMC samples are compared to the corresponding monolithic matrix material to investigate the key roles of particles in grain refinement and material strengthening. It is found that a small portion of particles is beneficial for grain refinement while maintaining the integrity of th...
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#1Yuntian Zhu (NCSU: North Carolina State University)H-Index: 111
#2Kei Ameyama (Rits: Ritsumeikan University)H-Index: 30
Last. Xiaolei Wu (CAS: Chinese Academy of Sciences)H-Index: 44
view all 13 authors...
Heterostructured materials are an emerging class of materials with superior performances that are unattainable by their conventional homogeneous counterparts. They consist of heterogeneous zones wi...
17 CitationsSource
#1Jinfeng Nie (Nanjing University of Science and Technology)H-Index: 16
#2Yuyao Chen (Nanjing University of Science and Technology)H-Index: 2
Last. Yuntian Zhu (SEU: Southeast University)H-Index: 111
view all 7 authors...
Abstract In this study, we report a liquid-solid reaction method combined with preferential particle orientation for fabricating a heterostructured Al3BC/6061 composite with ultrahigh Young's modulus (105 GPa), high tensile strength (495 MPa) and reasonable ductility (6.2%). The preferential orientation of Al3BC nanoplatelets contributes to the ultrahigh stiffness, and heterogeneous grain structure of the Al matrix facilitates the development of hetero-deformation induced stress and extra strain...
2 CitationsSource
#1Peijian Shi (SHU: Shanghai University)H-Index: 2
#2Yunbo Zhong (SHU: Shanghai University)H-Index: 20
Last. Yuntian Zhu (Nanjing University of Science and Technology)H-Index: 111
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Abstract High strength of materials usually comes with low ductility due to the lost or short-lived strain hardening. Here, we uncover a sequentially-activated multistage strain hardening (SMSH) that allows for sustained and effective strain-hardening capability in strong ultrafine-grained eutectic high-entropy alloy (EHEA). Consequently, exceptional ductility is realized in an ultrafine-grained EHEA, accompanied with high ultimate strength. We demonstrate that the SMSH is derived from a coordin...
4 CitationsSource