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Microstructure and mechanical properties of the welding joint filled with microalloying 5183 aluminum welding wires

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International Journal of Minerals,Metallurgy and Materials 2014年第6期21卷 577-582页

作者： Zhen Xu Zhi-hao Zhao gao-song wang Chao Zhang Jian-zhong Cui The Key Laboratory of the Ministry of Education of China for Electromagnetic Processing of Materials Northeastern University

In this study, 7A52 aluminum alloy sheets of 4 mm in thickness were welded by tungsten inert gas welding using microalloying welding wires containing traces of Zr and Er. The influence of rare earth elements Zr and Er on the microstructure and mechanical properties of the welded joints was analyzed by optical microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, hardness testing, and tensile mechanical properties testing. Systematic analyses indicate that the addition of trace amounts of Er and Zr leads to the formation of fine Al3Er, Al3Zr, and Al3（Zr,Er） phases that favor significant grain refinement in the weld zone. Besides, the tensile strength and hardness of the welded joints were obviously improved with the addition of Er and Zr, as evidenced by the increase in tensile strength and elongation by 40 MPa and 1.4%, respectively, and by the welding coefficient of 73%.

关键词： aluminum alloys inert gas welding rare earth elements microalloying joints microstructure mechanical properties

Structures and macrosegregation of a 2024 aluminum alloy fabricated by direct chill casting with double cooling field

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China Foundry 2022年第1期19卷 1-8页

作者： Cheng Zhu Zhi-hao Zhao Qing-feng Zhu gao-song wang Yu-bo Zuo gao-wu Qin Research Center for Metallic Wires School of Materials Science and EngineeringNortheastern UniversityShenyang 110819China Key Laboratory of Electromagnetic Processing of Materials Ministry of EducationNortheastern UniversityShenyang 110819China Key Laboratory of Anisotropy and Texture of Materials Ministry of EducationNortheastern UniversityShenyang 110819China

Central region coarse grains and centerline segregation are common defects in aluminum ingots fabricated by direct chill(DC)casting.A double cooling field was introduced into the DC casting process to reduce these defects,whereby the external cooling was supplied by the mold and water jets,and intercooling was achieved by inserting a rod of the same alloy into the molten pool along the central axis of the *** than forming a good metallurgical interface during solid-liquid compound casting,in the present work,the purpose of inserting the rod is to enforce internal cooling and consequently decrease the sump ***,the insertion provides more nucleation sites with the unmoltenα-Al *** structure and the macrosegregation of 2024 Al alloy ingots prepared by DC casting with and without the inserts were *** show that when the inserting position is 50 mm above the upper edge of the graphite ring,significant grain refinement in the central region of the ingot and a reduced centerline segregation are achieved.

关键词： aluminum alloy direct chill casting double cooling field grain refinement macrosegregation

Investigation on Reaction Interface between the Aluminum and K2ZrF6 by Freezing the Molten Salt Reaction

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Acta Metallurgica Sinica(English Letters) 2017年第5期30卷 433-437页

作者： Qing-Feng Zhu Fei Li Lei Li Wen-Jing wang gao-song wang Jian-Zhong Cui Key Laboratory of Electromagnetic Processing of Materials Ministry of EducationNortheastern UniversityShenyang 110819China School of Materials Science and Engineering Northeastern UniversityShenyang 110819China

A reaction interface between the aluminum and K_2ZrF_6 during molten salt reaction process was frozen by quenching the mold in water, and the interface structure was analyzed to determine the formation process of Al_3Zr. Results show that a clear conical interface existed between the K_2ZrF_6 and aluminum. A zirconium accumulation layer with the thickness of about 2–3 lm was formed at the aluminum side of the interface. Many initially formed Al_3Zr particles（with the size of 0.4–16 lm） distributed in this layer, most of which located at the interface. The morphology of Al_3Zr particles is closely related with their size. For the size of 0.4–1 lm, the Al_3Zr appeared as globular and ellipsoid shapes. When it grew to the size of 1–2 and 2–16 lm, it exhibited the rule cube shape, and rule cuboids shape, respectively.

关键词： Molten salt reaction Interface Aluminum Al3Zr particle Solidification

As-cast structure of DC casting 7075 aluminum alloy obtained under dual-frequency electromagnetic field

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International Journal of Minerals,Metallurgy and Materials 2014年第2期21卷 150-154页

作者： Zhi-hao Zhao Zhen Xu gao-song wang Qing-feng Zhu Jian-zhong Cui The Key Laboratory of the Ministry of Education of China for Electromagnetic Processing of Materials Northeastern University

We have experimentally determined the as-cast structures of semi-continuous casting 7075 aluminum alloy obtained in the pres-ence of dual-frequency electromagnetic field. Results suggest that the use of dual-frequency electromagnetic field during the semi-continuous casting process of 7075 aluminum alloy ingots reduces the thickness of the surface segregation layer, increases the height of the melt menis-cus, enhances the surface quality of the ingot, and changes the surface morphology of the melt pool. Moreover, low-frequency electromag-netic field was found to show the most obvious influence on improving the as-cast structure because of its high permeability in conductors.

关键词： electromagnetic fields: semi-continuous casting aluminum alloys as-cast structure

Dynamic and Static Aging Precipitation of β-Mg_(17)Al_(12) in the AZ80 Magnesium Alloy During Multi-directional Forging and Subsequent Aging

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Acta Metallurgica Sinica(English Letters) 2017年第10期30卷 941-948页

作者： Qing-Feng Zhu gao-song wang En-Ge Zhang Fan-Zheng Liu Zhi-Qiang Zhang Jian-Zhong Cui Key Laboratory of Electromagnetic Processing of Materials Ministry of EducationNortheastern University School of Materials Science and Engineering Northeastern University

Dynamic and static aging precipitation of Mg17Al12 phases in AZ80 magnesium alloy was studied by multidirectional forging（MDF） with decreasing temperatures from 410 to 300 ℃ and subsequent aging process. The results show that the morphology of the β-Mg17Al12 phases during forging process dynamically precipitates and aging process（statically precipitation） exhibited granular and laminar shapes, respectively. During the MDF, the inhomogeneous dynamic precipitation of the β-Mg17Al12 phases results in the uniformity on grain size, which is fine in the area with many granular Mg17Al12 phases but the grain is still coarse where there is no Mg17Al12 phases. During the aging process, the morphology of newly formed β-Mg17Al12 phases depends on the structural character of the forged sample. The newly precipitated β-Mg17Al12 phases are coarse laminar and needle-like shape in area with coarse grain. While, the fine newly precipitated β-Mg17Al12 phases are fine granular and needle-like in the area with fine grain.

关键词： Dynamic strain aging Precipitation AZ80 magnesium alloy Multi-directional forging Dynamic recrystallization

Effects of diffusion time and diffusion gradient strength on the mean diffusivity of water molecules in healthy human brain

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Progress in Natural Science:Materials International 2006年第7期16卷 706-711页

作者： gao song, wang Xiaoying and BAO Shanglian ( Laboratory of Medical Physics & Engineering, Peking University, Beijing 100871, China Department of Radiology, The First Affiliated Hospital of Peking University, Beijing 100034, China) Peking Univ Lab Med Phys & Engn Beijing 100871 Peoples R China Peking Univ Affiliated Hosp 1 Dept Radiol Beijing 100034 Peoples R China

Diffusion time and diffusion gradient strength are two important parameters of pulsed gradient spin echo (PGSE) that is the most commonly used method in diffusion-weighted magnetic resonance imaging. However, the effects of the diffusion time on the mean diffusivity (MD) in previous studies are controversial. In this study, a new experimental protocol was designed to evaluate the effects of the two parameters on the results of PGSE. It was found that MD decreased significantly with the increased diffusion time or increased diffusion gradient strength, which cannot be explained by the previous theories. Through theoretical analysis, we found the flaw in the pulsed gradient spin echo (PGSE) method, which is the explanation for the controversial results of diffusion time obtained by oth- ers.

关键词： diffusion time diffusion gradient strength diffusion-weighted imaging diffusion tensor imaging mean diffusivity.

Constraints on holographic QCD phase transitions from PTA observations

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Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 71-78页

作者： song He Li Li Sai wang Shao-Jiang wang Center for Theoretical Physics and College of Physics Jilin University School of Physical Science and Technology Ningbo University Max Planck Institute for Gravitational Physics (Albert Einstein Institute) CAS Key Laboratory of Theoretical Physics Institute of Theoretical Physics Chinese Academy of Sciences School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of Sciences (UCAS) School of Physical Sciences University of Chinese Academy of Sciences (UCAS) Theoretical Physics Division Institute of High Energy Physics Chinese Academy of Sciences

The underlying physics of QCD phase transition in the early Universe remains largely unknown due to its strong-coupling nature during the quark-gluon plasma/hadron gas transition, yet a holographic model has been proposed to quantitatively fit the lattice QCD data while with its duration of the first-order phase transition(FoPT) left undetermined. At specific baryon chemical potential, the first-order QCD phase transition agrees with the observational constraint of baryon asymmetry. It, therefore, provides a scenario for phase transition gravitational waves(GWs) within the standard model of particle physics. If these background GWs could contribute dominantly to the recently claimed common-spectrum red noise from pulsar timing array(PTA) observations, the duration of this FoPT can be well constrained, and the associated primordial black holes are still allowed by current observations.

关键词： pulsar timing array QCD phase transition gravitational waves primordial black holes

原位聚合-化学镀制备Cu_9S_5/PANI/涤纶导电纤维及其微观结构

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电镀与涂饰 2016年第21期35卷 1116-1121页

作者：高嵩王锋陶睿沈阳化工大学应用化学学院辽宁沈阳110142

先采用原位聚合法在涤纶纤维表面制备聚苯胺（PANI）导电层，再以CuS04-Na2S203体系化学镀，得到CugS5／PANI／涤纶导电纤维。探讨了原位聚合中各组分浓度和工艺条件对纤维导电性和增重率的影响。控制浴比为1：40，先用0．3mol／L苯胺＋... 详细信息

先采用原位聚合法在涤纶纤维表面制备聚苯胺（PANI）导电层，再以CuS04-Na2S203体系化学镀，得到CugS5／PANI／涤纶导电纤维。探讨了原位聚合中各组分浓度和工艺条件对纤维导电性和增重率的影响。控制浴比为1：40，先用0．3mol／L苯胺＋lmol／L盐酸溶液室温浸泡涤纶纤维30min，再向其中缓慢滴加0．3mol／L的过硫酸铵反应60min，所得PANI／涤纶纤维的导电性最好。采用红外光谱仪、扫描电镜、X射线衍射仪等对PANI／涤纶纤维和Cu9Ss／PANI／涤纶纤维的显微结构进行表征。结果表明，采用原位聚合讹学镀法可在涤纶纤维表面成功制备Cu9Ss／PANI复合层，所得Cu9Ss／PANI／涤纶导电纤维表面平整、均匀、致密，平均比电阻为7．29×10^2Ω／cm，导电性远远优于PANI／涤纶导电纤维（平均比电阻为2．12×10^4Ω/cm）。

关键词：涤纶纤维聚苯胺原位聚合五硫化九铜化学镀微观结构比电阻

Universal design of three-dimensional porous graphene-iron based promotors for kinetically rationalized lithium-sulfur chemistry

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Journal of Energy Chemistry 2025年第1期100卷 192-200页

作者： Hua gao Yunfeng Zhang Menglei wang Ruoxuan Yang Shuai Feng Xuan Cao Yaping Zhang Zhongyuan Lu Yingze song State Key Laboratory of Environment-Friendly Energy Materials School of Materials and Chemistry Southwest University of Science and Technology School of Material Science and Engineering Henan University of Technology College of Chemistry and Chemical Engineering Taishan University

Lithium-sulfur （Li-S） batteries are widely deemed to be one of the most potential candidates for future secondary batteries because of their remarkable energy ***,notorious polysulfide shuttling and retarded sulfur reaction kinetics pose significant obstacles to the further application of Li-S *** rationally designed highly active electrocatalysts can facilitate polysulfide conversion,the universal and scalable synthesis strategies need to be ***,a universal synthetic strategy to construct a series of three-dimensional （3D） porous graphene-iron （3DGr-Fe） based electrocatalysts involving 3DGr-FeP,3DGr-Fe3C,and 3DGr-Fe3Se4is exploited for manipulating the Li-S redox *** has been observed that the implementation of a 3D porous Gr architecture leads to the well-designed conductive networks,while the uniformly dispersed iron nanoparticles introduce an abundance of active sites,fostering the lithium polysulfide conversion,thereby bolstering the overall electrochemical *** Li-S battery with the 3DGr-Fe based electrocatalyst exhibits remarkable capacity retention of 94.8%upon 100 times at 0.2 ***,the soft-packaged Li-S pouch cell based on such a 3DGr-Fe electrocatalyst delivers superior capacity of 1060.71 mA h g-1and guarantees for the continuous 30 min work of fan *** investigation gives comprehensive insights into the design,synthesis,and mechanism of 3DGr-Fe based electrocatalysts with high activity toward efficient and durable Li-S batteries.

关键词： Lithium-sulfur battery Universal synthesis 3D graphene-iron based promotor Electrocatalysis