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Abnormal grain growth induced byδ→γphase transformation in Fe-based shape memory alloys

Journal of Materials Science & Technology 2024年第5期172卷 196-201页

作者： Huabei Peng liqiu yong Gaixia Wang Jiazhen Yan Bing Xu Yuhua Wen School of Mechanical Engineering Sichuan UniversityChengdu 610065China Science and Technology on Reactor Fuel and Materials Laboratory Nuclear Power Institute of ChinaChengdu 610041China

Grain boundaries,including low-angle,high-angle,and coinci-dence boundaries,are intrinsic interfaces in polycrystalline materi-als.During heat-treatment at sufficiently high temperatures,grain boundary migration occurs because the grain boundaries are ther-modynamically unstable.Consequently,grain growth occurs due to a decrease in grain boundary area after heat-treatment[1].In general,there are two types of grain growth:normal grain growth,where grains grow uniformly,and abnormal grain growth,where one or a few grains selectively grow and engulf surround-ing smaller grains,leading to the formation of large grains,some-times several millimeters or greater in size[2].The classical tech-nique to achieve abnormal grain growth is the strain-annealing method,which involves subjecting the material to a small strain followed by annealing[3,4].This method has been reported to ob-tain single-crystal wires or plates[1].Additionally,abnormal grain growth can be achieved by plastic straining at high temperatures,resulting in the fabrication of large grains or single crystals[5].However,the above methods are not applicable to components with complicated shapes due to the inevitable deformation pro-cess.Recently,Omori et al.developed a simply method of abnor-mal grain growth to fabricate ultra-large grains,even single crys-tals,in Cu-Al-Mn[1],Fe-Mn-Al-Ni[2],and Fe-Mn-Al-Ni-Cr[6]al-loys.This method involves applying cyclic heat treatment between a high temperature BCC single-phase region and a low tempera-ture BCC+FCC two-phase region[1,2,6-12].Note that the cyclic heat treatment resulted in the formation of BCC sub-grain struc-tures responsible for abnormal grain growth[1,2,6-12].In addition,Yang et al.reported that abnormal grain growth occurred at above 900℃,and large-grains,even single crystals,were obtained only through annealing cast Cu-based polycrystalline alloys contained coherent nano-particles[13,14].Notably,the cyclic heat treatment and annealing cast alloys are deformation-free and much simpler than the strain-anne

关键词： grain alloys deformation

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Effect of cyclic heat treatment on abnormal grain growth in Fe-Mn-Al-based shape memory alloys with different Ni contents

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Journal of Materials Science & Technology 2023年第22期153卷 8-21页

作者： Huabei Peng liqiu yong Yang Zuo Jiazhen Yan Hui Wang Yuhua Wen School of Mechanical Engineering Sichuan UniversityChengdu 610065China Key Laboratory of Radiation Physics and Technology of Ministry of Education Institute of Nuclear Science and TechnologySichuan UniversityChengdu 610064China Interdisciplinary Materials Research Center Institute for Advanced StudyChengdu UniversityChengdu 610106China

Cyclic heat treatment that can continuously promote abnormal grain growth is widely used for the prepa-ration of single-crystal Fe-Mn-Al-based shape memory alloys.However,it takes a long time to prepare large-size Fe-Mn-Al-based alloy single crystals via the reported cyclic heat treatments.Meanwhile,the long-time cyclic heat treatment at high temperatures leads to the development of defects including oxidation and a decrease in Mn,which would deteriorate superelasticity in the Fe-Mn-Al-based shape memory alloys.To shorten the fabrication time of single crystals,the effect of the cyclic heat treatment process on the abnormal grain growth in the Fe-Mn-Al-based alloys with different Ni contents was systematically investigated.It is found that the abnormal grain growth of Fe-Mn-Al-based alloys was not significantly affected by the Ni contents(within 2.1 at.%-6.2 at.%).In addition,the abnormal grain growth could be promoted by 1-2℃ min^(-1) cooling rate,high solution temperature,and multiple cycles,while it was insensitive to other processes including heating rate,dual-phase time as well as long-time solution treat-ment.These findings can guide optimizing the fabrication process of single crystals by cyclic heat treat-ment.Finally,the Fe_(41.9)Mn_(37.8)Al_(14.1) Ni_(6.2) single crystal prepared by the optimized cyclic heat treatment showed a recoverable strain of about 4%.

关键词： Cyclic heat treatment Ni content Abnormal grain growth Fe-Mn-Al-based shape memory alloy Superelasticity

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Deformation-induced interfacial-twin-boundary ω-phase in an Fe_(48)Mn_(37)Al_(15) body-centered cubic metastable alloy

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Journal of Materials Science & Technology 2023年第15期146卷 252-258页

作者： Huabei Peng Xiao Yang Lixin Sun liqiu yong Jiazhen Yan Jinyong Zhang Bingnan Qian Yuhua Wen School of Mechanical Engineering Sichuan UniversityChengdu 610065China School of Mechanical Engineering Hebei University of TechnologyTianjin 300401China State Key Laboratory of Materials Processing and Die and Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China School of Materials and Physics China University of Mining and TechnologyXuzhou 221116China State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China Innovation Center NPU ChongqingChongqing 401135China Department of Mechanical and Energy Engineering Southern University of Science and TechnologyShenzhen 518055China

Omega(ω)phase has a trigonal or hexagonal crystal structure and was first discovered inβ-type Ti-Cr alloys[1].Since then,theω-phase has been widely reported in numerous group IV transition metal(Ti,Ta,Hf,and Zr)based alloys[2–9].The morphologies ofω-phase could be particle-like(athermalω-phase)[10],ellipsoidal or cuboidal after aging(isothermalω-phase)[11],and plate-like after deformation(stress-relatedω-phase)[12].Amongst,the stressrelatedω-phase is usually located at the twinning boundary,thus also called interfacial-twin-boundary-ω(ITB-ω)phase.The formation of the ITB-ωphase is considered to be related to the formation of{112}bccmechanical twin(i.e.,{112}bcc twin)in bodycentered cubic(BCC)metals and alloys[13].

关键词： alloys alloy deformation

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Effect of additive boron on type-Ib gem diamond single crystals synthesized under HPHT

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Chinese Science Bulletin 2010年第8期55卷 677-679页

作者： MA liqiu MA HongAn XIAO HongYu LI ShangSheng LI yong JIA XiaoPeng National Key Laboratory of Super Hard Materials Jilin University Changchun 130012 China Institute of Material Science and Engineering Henan Polytechnic University Jiaozuo 454000 China

The boron-doped type-Ib gem diamond crystals were synthesized successfully by adding amorphous boron into a system of graphite and Kovar catalyst under high pressure and high temperature (HPHT).The effect of additive boron on type-Ib gem diamond was extensively studied including the growth characteristic,morphology and nitrogen concentration.The synthesized boron-doped type-Ib gem diamond crystals were characterized by optical microscope (OM),scanning electron microscope (SEM) and infrared spectrometer (IR).The results show that the growth region of the {111} face becomes wide,whereas the growth region of the {100} face becomes narrow and nearly disappears as increasing additive boron in the sample.The crystal will be opaque and imperfect,and the concentration of nitrogen will be decreased when the boron atoms are incorporated into gem diamond lattice.These techniques are very important and will be widely applied.

关键词：宝石级金刚石高温高压硼原子添加剂金刚石单晶合成类型金刚石晶体

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Effects of carbon diffusing field in alloy solvent on the growth of tower-shape diamond single crystal

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Chinese Science Bulletin 2010年第1期55卷 7-10页

作者： XIAO HongYu MA HongAn TIAN Yu LI Rui LI ShangSheng MA liqiu LI yong JIA XiaoPeng State Key Laboratory of Superhard Materials Jilin University Changchun 130012 China School of Materials Science and Engineering Henan Polytechnic University Jiaozuo 454000 China School of Materials Science and Engineering Changchun University of Science and Technology Changchun 130012 China

High-quality type-Ib tower-shape diamond single crystals were synthesized in cubic anvil high pressure apparatus (SPD-6×1200) at 5.4 GPa and 1250-1450°C. The (100) face of seed crystal was used as the growth face, and FeNiMnCo alloy was used as the solvent/catalyst. Two kinds of carbon diffusing fields (type-B and type-G) were simulated by finite element method (FEM). Using the two kinds of carbon diffusing fields, many diamond single crystals were synthesized. The effects of carbon diffusing fields on the crystal quality and β value (the ratio of height to diameter of diamond crystal) were studied. The results show that using type-B diffusing field, considerable inclusions appeared in tower-shape diamond crystals with high β values; however, using type- G diffusing field, inclusions were reduced markedly in high β values tower-shape diamond crystals, and the crystal, up to 0.6 carat in weight and 5.3 mm in size, was synthesized. Experimental phenomena were explained well with the help of the FEM.

关键词：金刚石单晶碳合金弥散效应塔型溶剂增长型金刚石晶体单晶合成

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Dependence of nitrogen concentration in type Ib diamonds on synthesis temperature

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Chinese Science Bulletin 2009年第9期54卷 1459-1462页

作者： TIAN Yu JIA XiaoPeng ZANG ChuanYi LI ShangSheng XIAO HongYu ZHANG YaFei HUANG GuoFeng LI Rui HAN QiGang MA liqiu LI yong CHEN XiaoZhou ZHANG Chong MA HongAn State Key Laboratory of Superhard Materials Jilin University Changchun 130012 China School of Materials Science and Engineering Henan Polytechnic University Jiazuo 454000 China School of Materials Science and Engineering Changchun University of Science and Technology Changchun 130012 China

Type Ib diamonds were grown by the temperature gradient method (TGM) at 5.5 GPa and 1500-1560 K in a china-type cubic anvil high pressure apparatus using Ni70Mn25Co5 alloy as solvent/catalyst. The concentration of nitrogen (CN) in type Ib diamonds synthesized at different synthesis temperatures was measured by a Fourier transform infrared (FTIR) spectrometer. The dependence of CN in diamond on synthesis temperature was studied. For the type Ib diamonds synthesized using Ni70Mn25Co5 as catalyst, its CN decreases along with the increase of synthesis temperature.

关键词：合成温度合成钻石氮浓度 Ib 依赖型傅里叶变换红外光谱温度梯度法合成金刚石

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Linda问题:“齐当别”抉择模型的解释

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心理科学进展 2007年第5期15卷 735-742页

作者：刘立秋陆勇天津大学管理学院天津300072

大量有关人类归因判断的研究表明,人类经常违反理性概率公理。Tversky和Kahneman(1983)使用Linda问题等特定场景的研究发现,人们系统性地表现出违反理性推断标准,判断合取事件发生概率大于其组成事件发生概率,称之为合取谬误,并用人们... 详细信息

大量有关人类归因判断的研究表明,人类经常违反理性概率公理。Tversky和Kahneman(1983)使用Linda问题等特定场景的研究发现,人们系统性地表现出违反理性推断标准,判断合取事件发生概率大于其组成事件发生概率,称之为合取谬误,并用人们使用代表性启发式判断概率来解释该现象产生的原因。然而使用启发式观点对合取谬误现象进行解释过于模糊不清。该文首先介绍了合取谬误现象及其解释模型,然后应用Li(1994,2004)提出的不确定情形下决策理论——"齐当别"抉择模型对Linda问题中合取谬误产生的原因进行了新的解释。

关键词：主观概率逻辑推断合取谬误齐当别模型

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融合集对分析和关联规则的变压器故障诊断方法

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中国电机工程学报 2015年第2期35卷 277-286页

作者：谢龙君李黎程勇卢明姜立秋腾云强电磁工程与新技术国家重点实验室(华中科技大学) 湖北省武汉市430074 国网河南省电力公司电力科学研究院河南省郑州市450052

结合集对分析和关联规则各自的特点,提出了一种电力变压器故障诊断的新方法。该方法通过分析变压器运行中各故障征兆参数之间的关联性,建立了故障类型集合;通过对比计算关联规则的支持度与置信度,同时引入变权公式,得到故障类型和故障... 详细信息

结合集对分析和关联规则各自的特点,提出了一种电力变压器故障诊断的新方法。该方法通过分析变压器运行中各故障征兆参数之间的关联性,建立了故障类型集合;通过对比计算关联规则的支持度与置信度,同时引入变权公式,得到故障类型和故障征兆的权重系数,有效避免专家意见或经验的主观性的问题;根据集对分析的可扩展性,采用5元联系度提高变压器故障诊断中处理不确定性因素的精度。实例对比分析表明,与关联规则、集对分析方法相比,该方法具有较好的诊断效果,在多故障问题处理中也表现优异。

关键词：电力变压器故障诊断集对分析关联规则

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石油平台海管立管腐蚀修复

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涂料工业 2019年第4期49卷 75-79页

作者：郎东旭王立秋李勇中海石油(中国)有限公司曹妃甸作业公司

介绍了海管潮差区和飞溅区立管部分目前现有的几种传统腐蚀修复方法和水下高分子材料修复法,比较了现有传统修复方法与水下高分子材料修复法的优缺点,通过比较认为水下高分子材料修复法具有防腐性能好、结构强度高、耐温性好及施工方便... 详细信息

介绍了海管潮差区和飞溅区立管部分目前现有的几种传统腐蚀修复方法和水下高分子材料修复法,比较了现有传统修复方法与水下高分子材料修复法的优缺点,通过比较认为水下高分子材料修复法具有防腐性能好、结构强度高、耐温性好及施工方便快捷等优点。最后以渤海某油田2个平台海管立管腐蚀修复工程为案例,详细描述了利用水下高分子材料修复海管立管的具体实施过程。

关键词：海管立管腐蚀修复潮差区飞溅区

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Simulation of the effect of a magnetically insulated anode on a low-power cylindrical Hall thruster

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Plasma Science and Technology 2018年第3期20卷 156-162页

作者：丁永杰李鸿贾伯阳李朋魏立秋徐宇彭武吉孙鹤芝曹勇于达仁 School of Energy Science and Engineering Harbin Institute of Technology Harbin 150001 People'sRepublic of China Harbin Institute of Technology (Shenzhen) Shenzhen 518055 People's Republic of China

The intersection point of the characteristic magnetic field line（CMFL） crossing the anode boundary with the discharge channel wall, and its influence on thruster performance and the energy and flux of ions bombarding the channel wall, have been studied numerically. The simulation results demonstrate that with the increase in distance from the crossover point of the CMFL with the channel wall to the bottom of the thruster channel, the ionization rate in the discharge channel gradually increases; meanwhile, the ion energy and ion current density bombarding the channel wall decreases. When the point of the CMFL with the channel wall is at the channel outlet, the thrust, specific impulse, and efficiency are at a maximum, while the ion energy and ion current density bombarding the channel wall are at a minimum. Therefore, to improve the performance and lifetime of the thruster, it is important to control the point of intersection of the CMFL with the channel wall.

关键词： magnetically insulated anode cylindrical Hall thruster performance

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