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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

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 characteristics.Therefore,HTS bulks have wide application potentials in maglev trains,maglev bearings,flywheel energy storage,drug delivery,and high field magnets.In the external magnetic field of common application scenarios,HTS bulks have no external input current,so it is difficult to achieve the overall quench.However,local quenching in the bulk is still possible in the harsh fluctuating external field environment.Although it is difficult to reach the total quench,its critical parameters like Jc will inevitably deteriorate,which may collapse the application system.Therefore,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 force.Therefore,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 fields.These methods primarily refer to the current quench detection technologies used in HTS tapes and wires.From 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 principles.They 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

Erratum to“Review on thermal-related measurement methods for superconducting devices and prospect for high-speed maglev transportation application”[Superconductivity 3(2022)100020]

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Superconductivity 2023年第1期5卷 75-75页

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

The publisher regrets to publish this article without“Declaration of Competing Interest”.The publisher would like to apologise for any inconvenience caused.The below“Declaration of interests”text should be added.Declaration of interests The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

关键词： interests application prospect

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 Al was added for the final deoxidation during the smelting process of the Grade B+Steel, residual Al existed to some extent in the castings. High residual Al content in the bogie casting was presumed to be the reason for the fracture. In this work, the influence of residual Al 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 Al 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 Al 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 Al 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 Al 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 Al content mechanical properties

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

Zn元素对Mg-6Al-2Nd-2Ca组织和性能的影响

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稀有金属材料与工程 2022年第9期51卷 3482-3491页

作者：何翰霖王丽萍冯义成赵思聪王雷郭二军哈尔滨理工大学材料科学与化学工程学院黑龙江哈尔滨150040

采用金属型重力铸造方法制备了Mg-6Al-2Nd-2Ca和Mg-6Al-2Nd-2Ca-1.2Zn合金,并对铸态合金进行均匀化处理和热挤压加工,通过OM、XRD、SEM、EDS、TEM和万能试验机等分析测试方法,研究了Zn元素对Mg-6Al-2Nd-2Ca合金显微组织和力学性能的影... 详细信息

采用金属型重力铸造方法制备了Mg-6Al-2Nd-2Ca和Mg-6Al-2Nd-2Ca-1.2Zn合金,并对铸态合金进行均匀化处理和热挤压加工,通过OM、XRD、SEM、EDS、TEM和万能试验机等分析测试方法,研究了Zn元素对Mg-6Al-2Nd-2Ca合金显微组织和力学性能的影响。结果表明:Zn元素的加入有助于细化晶粒,Zn在合金中主要以固溶体的形式存在,降低了Al在α-Mg基体中的固溶度,生成更多的Al-Nd相。2种合金经过均匀化处理后,与铸态相比显微组织更加均匀,第二相数量略有减少。经热挤压后,2种合金中的硬脆相被挤碎,晶粒得到明显的细化,力学性能明显提升,在细晶强化、第二相强化的共同作用下Mg-6Al-2Nd-2Ca-1.2Zn合金表现出优良的力学性能,其抗拉强度、屈服强度和断后伸长率分别为294.0 MPa、197.1 MPa、11.6%。

关键词： Mg合金 Zn元素热挤压显微组织力学性能

Mg-6Al-2Nd-xCa系耐热镁合金凝固路径分析

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特种铸造及有色合金 2022年第11期42卷 1419-1424页

作者：邢斯翀冯义成王雷王丽萍赵思聪哈尔滨理工大学材料科学与化学工程学院哈尔滨150040

以Mg-Al-Nd-Ca合金为研究对象,通过测定不同Mg-6Al-2Nd-xCa合金(x=0、0.5、1.0、1.5、2.0、2.5、3.0,%,质量分数)凝固曲线,并通过重熔-等温液淬试验及XRD、OM、SEM、EDS等分析手段,研究了Ca对Mg-6Al-2Nd合金相形成及凝固路径的影响。结... 详细信息

以Mg-Al-Nd-Ca合金为研究对象,通过测定不同Mg-6Al-2Nd-xCa合金(x=0、0.5、1.0、1.5、2.0、2.5、3.0,%,质量分数)凝固曲线,并通过重熔-等温液淬试验及XRD、OM、SEM、EDS等分析手段,研究了Ca对Mg-6Al-2Nd合金相形成及凝固路径的影响。结果表明,随着Ca含量增加,Al_(11)Nd_(3)和β-Mg_(17)Al_(12)相含量减少,Al2Ca相增多。α-Mg、Al_(2)Nd、Al_(11)Nd_(3)相的析出温度均随Ca含量的升高而降低,其中α-Mg相的析出温度由620℃下降至606℃,Al_(2)Nd相的析出温度由630℃下降至610℃,而Al_(2)Ca相的析出温度则由504℃升高至529℃。Mg-6Al-2Nd_(-x)Ca(x=0、0.5,%)合金的凝固路径为L→Al_(2)Nd;L→α-Mg;L_(Al)+Al_(2)Nd→Al_(11)Nd_(3);L→α-Mg+β-Mg_(17)Al_(12)。Mg-6Al-2Nd_(-x)Ca合金(x=1.0、1.5、2.0、2.5、3.0,%)的凝固路径为L→Al_(2)Nd;L→α-Mg;L→α-Mg+Al_(2)Ca。重熔-等温液淬试验结果表明,等温液淬试验结果与凝固曲线分析结果一致。

关键词：镁合金凝固路径显微组织等温液淬

硅含量对耐热球墨铸铁显微组织和力学性能的影响

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金属热处理 2022年第9期47卷 227-233页

作者：赵竞王丽萍冯义成姜文勇王雷郭二军哈尔滨理工大学材料科学与化学工程学院黑龙江哈尔滨150040

采用光学显微镜、扫描电镜、电子万能拉伸试验机测试分析手段,研究硅含量对耐热球墨铸铁显微组织和室温、高温力学性能的影响规律。试验结果表明,随着硅含量的增加,石墨圆整度逐渐下降,硅含量(质量分数,下同)达到3.8%时,基体中开始出现... 详细信息

采用光学显微镜、扫描电镜、电子万能拉伸试验机测试分析手段,研究硅含量对耐热球墨铸铁显微组织和室温、高温力学性能的影响规律。试验结果表明,随着硅含量的增加,石墨圆整度逐渐下降,硅含量(质量分数,下同)达到3.8%时,基体中开始出现碎块状石墨,球化级别为3级。随着硅含量从2.8%增加至4.8%,珠光体含量从51.06%减少至8.65%。随着硅含量的增加,室温抗拉强度先上升后下降,伸长率逐渐下降,当硅含量为3.8%时,抗拉强度为726 MPa,伸长率为1.6%。随着硅含量的增加,高温抗拉强度逐渐上升,伸长率逐渐下降,当硅含量为4.8%时,抗拉强度为532 MPa,伸长率为6%。室温拉伸断口出现大量的解理面和河流花样,表现形式为脆性断裂。高温拉伸断口出现韧窝和撕裂棱,拉伸断口表现形式为韧-脆混合型断裂。

关键词：耐热球墨铸铁显微组织室温性能高温性能断口形貌

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结核性脑膜炎诊断新技术的现状与进展

中华神经科杂志 2024年第3期57卷 302-308页

作者：李一澄王婷黄温勉冯国栋复旦大学附属中山医院神经内科上海200032 华南理工大学附属第二医院(广州市第一人民医院)神经内科广州510180

结核性脑膜炎是由结核分枝杆菌引起的中枢神经系统感染性疾病,其临床表现缺乏特异性,而传统病原学对其诊断效率较低,易导致延误诊断和治疗、影响患者预后,因此早期快速的病原学诊断对结核性脑膜炎的诊治至关重要。文中对近年来出现的可... 详细信息

结核性脑膜炎是由结核分枝杆菌引起的中枢神经系统感染性疾病,其临床表现缺乏特异性,而传统病原学对其诊断效率较低,易导致延误诊断和治疗、影响患者预后,因此早期快速的病原学诊断对结核性脑膜炎的诊治至关重要。文中对近年来出现的可用于诊断结核性脑膜炎的新型检测技术进行综述,主要分为核酸检测方法、代谢组学和蛋白组学3个方面,并在此基础上对未来发展作出展望。

关键词：中枢神经系统感染结核脑膜诊断