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Microstructure in the Semi-solid State and Mechanical Properties of AZ80 Magnesium Alloy Reheated from the As-cast and Extruded States

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Acta Metallurgica Sinica(English Letters) 2013年第4期26卷 473-482页

作者： Wenyong JIANG Tian CHEN Liping WANG yicheng feng Yan ZHU Kaifeng WANG Jiapeng LUO Shouwei ZHANG College of Materials Science and Engineering Harbin University of Science and Technology

The multi-axial forging （MAF） process was introduced into the strain induced metal activation （SIMA） process to replace conventional forging. Microstructure evolution of MAF formed AZ80 magnesium alloy during partial remelting was investigated. Furthermore, the tensile mechanical properties for AZ80 magnesium alloy thixoextruded from the starting materials treated by MAF were determined. For comparison, as-cast AZ80 magnesium alloy was also thixoextruded. The results show that the SIMA route produced ideal, fine semi-solid microstructure, in which almost completely spheroidal primary solid grains had a little amount of entrapped liquid. The microstructure of the as-cast alloy in the semi-solid state is less spheroidized compared with the MAF alloy under the similar isothermal holding conditions. With prolonged holding time, the size of the solid grain increases and the degree of spheroidization is improved in the MAF formed alloys. However, the solid grain size of the as-cast alloys decreases initially, and then increases with further increasing temperature. The tensile mechanical properties for AZ80 magnesium alloy thixoextruded from the starting material produced by MAF are better than those of AZ80 magnesium alloy thixoextruded from the starting material produced by casting. The ultimate tensile strength, yield strength and elongation of the alloy thixoextruded from the starting material produced by MAF are 314 MPa, 238 MPa and 14%, respectively.

关键词： Magnesium alloy Microstructure Mechanical properties Partial remelting

Efect of residual Al content on microstructure and mechanical properties of Grade B+Steel for castings for locomotives

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China Foundry 2013年第6期10卷 391-395页

作者： Wang Kaifeng Guo Erjun Cao Guojian Wang Liping feng yicheng Jiang Wenyong Tao Chunguo College of Materials Science and Engineering Harbin University of Science and Technology Qiqihar Railway Rolling Stock (Group) Co. Ltd.

The bogie made of Grade B＋ steel is one of the most important parts of heavy haul trains. Some accidents were found to be the result of fracture failure of the bogies. It is very important to find the reason why the fracture failure occurred. Because AI was added for the final deoxidation during the smelting process of the Grade B＋Steel, residual AI existed to some extent in the castings. High residual AI content in the bogie casting was presumed to be the reason for the fracture. In this work, the influence of residual AI content in the range of 0.015wt.% to 0.3wt.% on the microstructure and mechanical properties of the Grade B＋ Steel was studied. The experimental results showed that when the residual AI content is between 0.02wt.% and 0.20wt.%, the mechanical properties of the steel meet the requirements of technical specification for heavy haul train parts, and the fracture is typical plastic fractures. If the residual AI content is less than 0.02wt.%, the microstructures are coarse, and the mechanical properties can not meet the demand of bogie steel castings. When the residual AI content is more than 0.2wt.%, the elongation, reduction of area, and low-temperature impact energy markedly deteriorate. The fracture mode then changes from plastic fracture to cleavage brittle fracture. Therefore, the amount of AI addition for the final deoxidation during the smelting process must be strictly controlled. The optimum addition amount needs to be controlled within the range of 0.02wt.% to 0.20wt.% for the Grade B＋Steel.

关键词： bogie Grade B+Steel AI content mechanical properties

Hydrodechlorination of trifluoro-trichloroethane to chlorotrifluoroethylene:Revealing the deactivation mechanism and regeneration strategy of Pd-Cu/AC catalyst

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Chinese Journal of Chemical Engineering 2024年第6期70卷 261-268页

作者： Song Tian yicheng Chen Xiaoyu Wen Bingcheng Li Jian Lu Zile Li feng feng Qingtao Wang Qunfeng Zhang Xiaonian Li State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology Institute of Industrial Catalysis of Zhejiang University of TechnologyHangzhou 310014China State Key Laboratory of Fluorine&Nitrogen Chemicals Xi'an Modern Chemistry Research InstituteXi'an 710065China

Chlorotrifluoroethylene(CTFE)is a vital fluorinated olefinic monomer produced through the catalytic hydrodechlorination of trichlorotrifluoroethane(CFC-113),an eco-friendly ***,hydrodechlorination catalysts for olefin production often suffer from poor *** Pd/AC catalyst and Pd-Cu/AC catalyst prepared by co-impregnation method exhibited poor stability,Pd-Cu/AC catalyst with CFC-113 conversion dropping to around 37%after 50 h of hydrodechlorination ***-Emmett-Teller,transmission electron microscopy,X-ray photoelectron spectroscopy,and X-ray diffraction of fresh and deactivated Pd/AC catalysts indicate that the deactivation of Pd/AC catalysts is due to high-temperature agglomeration of *** analysis of fresh and deactivated Pd-Cu/AC catalysts using Brunauer-Emmett-Teller,transmission electron microscopy,and thermogravimetric analysis techniques revealed decreased dispersion of active sites,reduced surface area,catalyst aggregation deactivation,and a significant decrease in Cu ***,the results of NH3-TPD revealed that the acid sites of the catalyst increased significantly.X-ray diffraction spectra indicated the formation of new species,basic copper chloride(Cu_(2)(OH)_(3)Cl),during the *** the reaction progressed,these new species agglomerated,leading to a gradual loss of catalyst ***,the deactivated catalyst was successfully reactivated using a simple alkaline washing method.

关键词： CFC-113 Hydrodechlorination Chlorotrifluoroethylene Catalyst deactivation

体外模拟胃肠消化过程中山楂的活性成分及抗氧化性规律

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食品科学 2018年第7期39卷 139-145页

作者：封易成牟德华河北科技大学生物科学与工程学院河北石家庄050000

为了研究体外模拟山楂胃肠消化过程中的活性成分及抗氧化性变化规律。本实验通过体外模拟山楂口腔消化液、胃消化液、肠消化液、肠透析液以及山楂提取液5种样品,测定其黄酮、多酚、多糖和有机酸含量变化,及5种样品对1,1-二苯基-2-三硝... 详细信息

为了研究体外模拟山楂胃肠消化过程中的活性成分及抗氧化性变化规律。本实验通过体外模拟山楂口腔消化液、胃消化液、肠消化液、肠透析液以及山楂提取液5种样品,测定其黄酮、多酚、多糖和有机酸含量变化,及5种样品对1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基、2,2’-联氮-二(3-乙基-苯并噻唑-6-磺酸)二铵盐(2,2’-azinobis-(3-ethylbenzothiazoline-6-sulphonate),ABTS)自由基、羟自由基清除能力及铁离子还原能力。结果表明:5种样品在模拟消化过程中活性成分具有相似的变化趋势,其中经口腔和胃消化后多糖和有机酸比消化前含量显著增加;5种样品清除DPPH自由基、ABTS^+·及还原铁离子能力的变化趋势相似,其中口腔和胃消化液抗氧化能力最强,肠透析液抗氧化能力最弱,而清除羟自由基能力的结果略有不同。从本研究中可以看出山楂在体内的消化产物具有较好的抗氧化活性。

关键词：山楂体外消化抗氧化活性成分

Review on thermal-related measurement methods for superconducting devices and prospect for high-speed maglev transportation application

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Superconductivity 2022年第3期3卷 83-96页

作者： Jun Zheng Minghui Wei Siyi Quan yicheng feng Peng Wen State Key Laboratory of Traction Power Southwest Jiaotong UniversityChengdu 610031People’s Republic of China

High‐temperature superconducting(HTS)bulks can not only be self‐stable when levitated above a permanent magnet(PM)but also can be used as quasi PM with higher magnetic energy product due to their magnetic flux pinning ***,HTS bulks have wide application potentials in maglev trains,maglev bearings,flywheel energy storage,drug delivery,and high field *** the external magnetic field of common application scenarios,HTS bulks have no external input current,so it is difficult to achieve the overall ***,local quenching in the bulk is still possible in the harsh fluctuating external field *** it is difficult to reach the total quench,its critical parameters like Jc will inevitably deteriorate,which may collapse the application ***,in contrast to superconducting wires and tapes that are more concerned with quench detection,HTS bulks with a 3D volume effect are more focused on internal sensitive temperature locations,the impacts of volume and scale,and the coupling influence on application parameters such as magnetism and ***,for efficient thermal‐related measurement of HTS bulk applications,this paper investigates and discusses 12 commonly‐used temperature measurement or quench detection methods in all superconducting application *** methods primarily refer to the current quench detection technologies used in HTS tapes and *** the standpoint of practical temperature measurement requirements of HTS bulks and technological limitations of maglev application scenarios,working characteristics and service conditions of the 12 methods,and 4 temperature detection methods are selected through a comprehensive understanding and comparison of basic *** are expected to be used in real‐time monitoring and early warning schemes for onboard superconducting levitation devices of HTS maglev transportation or other applications in the future.

关键词： High‐temperature superconducting bulk Temperature sensitivity High‐temperature superconducting magnetic levitation High‐temperature superconducting tape Quench detection Temperature detection

Gate Tunable Labyrinth Domain Structures in a van der Waals Itinerant Ferromagnet Cr_(7)Te_(8)

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Chinese Physics Letters 2024年第9期41卷 122-132页

作者： Kui Meng Zeya Li yicheng Shen Xiangyu Bi Junhao Rao Yuting Qian Zhansheng Gao Peng Chen Caiyu Qiu feng Qin Jinxiong Wu feng Luo Junwei Huang Hongtao Yuan National Laboratory of Solid State Microstructures Jiangsu Key Laboratory of Artificial Functional MaterialsCollege of Engineering and Applied Sciencesand Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210000China Center for the Physics of Low-Dimensional Materials Henan Joint International Research Laboratory of New Energy Materials and DevicesSchool of Physics and ElectronicsHenan UniversityKaifeng 475004China Tianjin Key Lab for Rare Earth Materials and Applications Center for Rare Earth and Inorganic Functional MaterialsSmart Sensor Interdisciplinary Science CenterSchool of Materials Science and EngineeringNankai UniversityTianjin 300350China

Manipulating magnetic domain structure plays a key role in advanced spintronics *** rationale is that the labyrinthine domain structure,normally appearing in ferromagnetic thin films with strong magnetic anisotropy,shows a great potential to increase data storage density for designing magnetic nonvolatile memory and logic ***,an electrical control of labyrinthine domain structure remains ***,we demonstrate the gate-driven evolution of labyrinthine domain structures in an itinerant ferromagnet Cr_(7)Te_(8).By combining electric transport measurements and micromagnetic finite difference simulations,we find that the hysteresis loop of anomalous Hall effect in Cr_(7)Te_(8)samples shows distinct features corresponding to the generation of labyrinthine domain *** labyrinthine domain structures are found to be electrically tunable via Li-electrolyte gating,and such gate-driven evolution in Cr_(7)Te_(8)originates from the reduction of the magnetic anisotropic energy with gating,revealed by our micromagnetic *** results on the gate control of anomalous Hall effect in an itinerant magnetic material provide an opportunity to understand the formation and evolution of labyrinthine domain structures,paving a new route towards electric-field driven spintronics.

关键词： rational electrolyte ferromagnetic

(WO_3p+ABOw)/Al混杂复合材料制备与力学性能

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稀有金属 2014年第5期38卷 813-818页

作者：冯义成范国华耿林王丽萍哈尔滨理工大学材料科学与工程学院黑龙江哈尔滨150040 哈尔滨工业大学材料科学与工程学院黑龙江哈尔滨150001

采用湿成型法成功制备了比重差别大的WO3颗粒(WO3p)和硼酸铝晶须(ABOw)混杂预制块,用挤压铸造法制备混杂铝基复合材料。混杂复合材料中含(原子分数)5%WO3p和20%ABOw,不同大小的WO3p尺寸分别为18和3μm。采用扫描电镜(SEM)和万能拉伸试... 详细信息

采用湿成型法成功制备了比重差别大的WO3颗粒(WO3p)和硼酸铝晶须(ABOw)混杂预制块,用挤压铸造法制备混杂铝基复合材料。混杂复合材料中含(原子分数)5%WO3p和20%ABOw,不同大小的WO3p尺寸分别为18和3μm。采用扫描电镜(SEM)和万能拉伸试验机对制备的混杂复合材料试样进行微观组织观察和拉伸性能测试。复合材料组织观察表明,WO3p和ABOw在基体中随机、均匀地分布,在高倍照片中可以观察到大尺寸WO3p存在裂纹,铝液不能渗入到裂纹中。力学性能研究结果表明,尺寸较小的颗粒增强的复合材料具有高的抗拉强度和断裂延伸率;含大尺寸WO3p的混杂复合材料的抗拉强度、屈服强度和断裂延伸率分别为266.8,197.3 MPa和1.16%,含小尺寸WO3p的混杂复合材料的抗拉强度、屈服强度和延伸率分别为290.3,180.5 MPa和1.37%。复合材料拉伸断口形貌观察表明,两种不同WO3p尺寸的混杂复合材料断裂机制有所不同,大颗粒增强复合材料中大颗粒发生断裂,裂纹穿过颗粒扩展,晶须与界面脱粘;小颗粒增强复合材料中小颗粒与基体界面脱粘以及晶须与界面脱粘,但晶须脱粘数量明显减少,晶须拔出数量增多。

关键词：混杂复合材料力学性能断裂机制

Bi对Mg-3Al-3Nd合金显微组织和力学性能的影响

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材料研究学报 2020年第6期34卷 425-433页

作者：陈亮王丽萍冯义成王雷赵思聪哈尔滨理工大学材料科学与工程学院哈尔滨150040

使用扫描电子显微镜(SEM)和光学显微镜(OM)观察、X-射线衍射(XRD)分析以及力学性能测试等手段研究了Bi含量对Mg-3Al-3Nd合金的显微组织和力学性能的影响。结果表明:添加Bi元素可细化Mg-3Al-3Nd合金的组织。当Bi含量(质量分数)为1%时晶... 详细信息

使用扫描电子显微镜(SEM)和光学显微镜(OM)观察、X-射线衍射(XRD)分析以及力学性能测试等手段研究了Bi含量对Mg-3Al-3Nd合金的显微组织和力学性能的影响。结果表明:添加Bi元素可细化Mg-3Al-3Nd合金的组织。当Bi含量(质量分数)为1%时晶粒最小,晶粒尺寸从1854±58μm减小到890±64μm;Mg-3Al-3Nd合金由呈网状分布在晶界的Al11Nd3相和分布在晶内的颗粒状Al2Nd组成;随着Bi含量的提高Al11Nd3相和Al2Nd相的数量减少,晶内的BiNd相数量增加;Bi能明显改善Mg-3Al-3Nd合金室温和高温力学性能,Bi含量为1%时其室温和高温力学性能最佳。室温抗拉强度和延伸率分别为167±2.3 MPa和(16.1±0.3)%,高温抗拉强度及延伸率分别为136±1.7 MPa和(19.3±0.3)%。

关键词：金属材料镁合金 Bi 显微组织力学性能

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喷射成形镍基高温合金时效行为（英文）

稀有金属材料与工程 2015年第12期44卷 2965-2969页

作者：康福伟曹福洋张雪敏岳红彦冯义成哈尔滨理工大学黑龙江哈尔滨150040 哈尔滨工业大学黑龙江哈尔滨150001

主要研究了喷射成形镍基高温合金的微观组织特征和时效硬化行为。合金经1140℃,8 h固溶处理,然后在780℃,2~12 h时效处理。分别测试了合金显微硬度、析出相大小及形态、电导率和正电子湮没寿命与时效时间的关系。结果表明,在时效8 h时,... 详细信息

主要研究了喷射成形镍基高温合金的微观组织特征和时效硬化行为。合金经1140℃,8 h固溶处理,然后在780℃,2~12 h时效处理。分别测试了合金显微硬度、析出相大小及形态、电导率和正电子湮没寿命与时效时间的关系。结果表明,在时效8 h时,显微硬度达到最大值,此时γ＇长大到临界尺寸56 nm。然而,时效时间超过8 h,合金显微硬度降低,这是由于γ＇长大超过了其临界尺寸。随着时效时间延长至6 h,电导率快速增加到其最大值32%IACS,但是正电子湮没寿命则降低到最小值149 ps,在时效时间为10 h时,正电子湮没寿命达到最大值297 ps。这是由在时效过程中γ＇尺寸的变化以及缺陷浓度的变化引起的。

关键词：时效硬化喷射成形电导率正电子湮没寿命