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Effect of edge cracks on critical current degradation in REBCO tapes under tensile stress

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Superconductivity 2022年第1期1卷 52-62页

作者： Zhirong Yang Yi Li Peng Song Mingzhi Guan Feng Feng timing qu State Key Laboratory of Tribology Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China Department of Mechanical Engineering Advanced Manufacturing InstituteTexas Center for SuperconductivityUniversity of HoustonHoustonTX 77024USA Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China Lab of Intelligent Manufacturing and Precision Machining Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China

The slitting process for manufacturing REBa2Cu3O7δ(REBCO,RE=Rare earth)tapes of required width significantly improves the production efficiency and reduces production ***,edge cracks induced by the slitting process of wide REBCO tapes may cause premature degradation under high tensile stress in highfield ***,it is necessary to evaluate the effect of edge cracks of REBCO tapes on the critical current(Ic)***,Ic degradation under artificial cracks was measured to validate the applicability of linear elastic fracture mechanics for the REBCO *** maximum circumferential stress criterion was used to derive the mixed-mode stress intensity factor of multiple oblique edge cracks.A semi-analytical model considering edge crack properties such as angleβ,spacing d,and length a,was built to evaluate the critical load and critical *** found that when the stress intensity factor at the crack tip is below KIC?2:3 MPa ffiffiffiffim p,edge cracks did not *** examined commercial REBCO tapes manufactured by two different processes,concluding that edge cracks in these tapes will not cause premature degradation.

关键词： REBCO Degradation Stress intensity factor Multiple oblique edge cracks Fracture toughness

Screening-current-induced magnetic fields and strains in a compact REBCO coil in self field and background field

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Superconductivity 2024年第1期9卷 35-49页

作者： Yufan Yan Donghui Jiang Peng Song Jeonghwan Park Seungyong Hahn Yunfei Tan timing qu Department of Electrical and Computer Engineering Seoul National UniversitySeoul 08826Republic of Korea State Key Laboratory of Clean and Efficient Turbomachinery Power Equipment Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China High Magnetic Field Laboratory Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China Wuhan National High Magnetic Field Center Huazhong University of Science and TechnologyWuhan 430074China

REBa_(2)Cu_(3)O_(7−x)(REBCO)coated conductors,owing to its high tensile strength and current‐carrying ability in a background field,are widely regarded a promising candidate in high‐field *** the great potentials,recent studies have highlighted the challenges posed by screening currents,which are featured by a highly nonuniform current distribution in the superconducting *** this paper,we report a comprehensive study on the behaviors of screening currents in a compact REBCO coil,specifically the screeningcurrent‐induced magnetic fields and *** were carried out in the self‐generated magnetic field and a background field,*** the self‐field condition,the full hysteresis of the magnetic field was obtained by applying current sweeps with repeatedly reversed polarity,as the nominal center field reached 9.17 T with a maximum peak current of 350 *** a background field of 23.15 T,the insert coil generated a center field of 4.17 T with an applied current of 170 ***,a total center field of 32.58 T was achieved before *** the sequential model and the coupled model considering the perpendicular field modification due to conductor deformation are *** comparative study shows that,for this coil,the electromagnetic–mechanical coupling plays a trivial role in self‐field conditions up to 9 *** contrast,with a high axial field dominated by the background field,the coupling effect has a stronger influence on the predicted current and strain *** discussions regarding the role of background field on the strains in the insert suggest potential design strategies to maximize the total center field.

关键词： Electromagnetic-mechanical analysis High‐field insert coil REBCO coated conductor Screening‐current‐induced magnetic field Screening‐current‐induced stress

A novel aluminum-carbon nanotubes nanocomposite with doubled strength and preserved electrical conductivity

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Nano Research 2021年第8期14卷 2776-2782页

作者： Shuai Zhang Gaoqiang Chen timing qu Jinquan Wei Yufan Yan qu Liu Mengran Zhou Gong Zhang Zhaoxia Zhou Huan Gao Dawei Yao Yuanwang Zhang Qingyu Shi Hua Zhang State Key Laboratory of Tribology Key Laboratory for Advanced Materials Processing Technology Ministry of Education of ChinaDepartment of Mechanical Engineering Tsinghua UniversityBeijing 100084China Key Lab for Advanced Materials Processing Technology of Education Ministry School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China Loughborough materials characterization center Department of materialsLoughborough UniversityLoughboroughLEU 3TUUK State Key Laboratory of Special Cable Technology Shanghai Electric Cable Research Institute Co.Ltd.Shanghai 200093China School of Mechanical Engineering Beijing Institute of Petrochemical Technology Beijing 102617China

Enhancing the mechanical strength of highly conductive pure metals usually causes significant reduction in their electrical *** example,introducing phase/matrix interfaces or more grain boundaries,are common and effective methods to strengthen *** it simultaneously increases the electron scattering at the interface,thus reducing the electrical *** this study,we demonstrate that pure aluminum(Al)/carbon nanotubes(CNTs)nanocomposites prepared by friction stir processing have successfully broken through these *** yield strength and tensile strength of Al/CNTs nanocomposites have improved by 104.7%and 51.8%compared to pure Al,while the electrical conductivity remained comparable to that of pure *** explore the potential mechanisms,the interface between CNTs and Al was examined and characterized by transmission electron microscopy(TEM)and Raman *** interfacial reaction compounds were present and no visible physical gaps were observed at CNTs and Al *** defined it as a clean and tightly bonded *** the quantity of phase interface has increased,the electrical conductivity of the nanocomposite remains approximately *** attribute the preserved electrical conductivity to the clean and tightly bonded CNTs/Al interface in the nanocomposite.

关键词： carbon nanotubes/aluminum nanocomposites mechanical properties electrical conductivity friction stir processing interface

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铋系高温超导粉体的制备

稀有金属材料与工程 2007年第A1期36卷 40-42页

作者：李明亚齐西伟瞿体明东北大学秦皇岛分校材料科学与工程系河北秦皇岛066004 清华大学物理系北京100084

首先采用喷雾热分解法制备了铋系超导粉体,然后对得到的粉体进行焙烧处理,焙烧时采用不同的工艺参数,包括温度、保护气体的氧分压等。利用XRD,SEM等分析手段,研究了焙烧后粉体的粒度分布,形貌,相组成及其均匀性等。最后,采用粉末套管法... 详细信息

首先采用喷雾热分解法制备了铋系超导粉体,然后对得到的粉体进行焙烧处理,焙烧时采用不同的工艺参数,包括温度、保护气体的氧分压等。利用XRD,SEM等分析手段,研究了焙烧后粉体的粒度分布,形貌,相组成及其均匀性等。最后,采用粉末套管法将焙烧后的超导粉体制备成单芯超导带材,在形变热处理后,带材样品获得了超过30A的临界电流。

关键词：铋系高温超导材料超导粉体喷雾热分解法 Bi-2223/Ag带材临界电流

用化学溶液法制备银基底Bi-2212超导薄膜

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稀有金属 2014年第5期38卷 749-754页

作者：邓舒同瞿体明林冠韩征和清华大学物理系应用超导研究中心北京100084 清华大学机械工程系摩擦学国家重点实验室北京100084 清华大学机械系先进成形制造教育部重点实验室北京100084

Bi2Sr2CaCu2Ox(Bi-2212)薄膜制备工艺相对简单,在低温下具有优异的性能,因此备受青睐,已经有不少研究小组采用真空或非真空方法成功制备出高质量的Bi-2212薄膜。一般而言,单晶基底被广泛用于Bi-2212薄膜的制备。与单晶基底不同,银基底... 详细信息

Bi2Sr2CaCu2Ox(Bi-2212)薄膜制备工艺相对简单,在低温下具有优异的性能,因此备受青睐,已经有不少研究小组采用真空或非真空方法成功制备出高质量的Bi-2212薄膜。一般而言,单晶基底被广泛用于Bi-2212薄膜的制备。与单晶基底不同,银基底无织构,但银基底的表面粗糙度等因素对Bi-2212的c轴织构和临界电流密度有影响。并且由于银基底对Bi系高温超导材料具有较低表面能,因此Bi-2212薄膜可以在银基底上稳定存在。以乙酸-氨水溶液为基础,开发了一种在银基底上制备Bi-2212薄膜的方法,对其中的关键步骤做了详细的研究,主要包括银基底的抛光、化学溶液的配制、烧结温度等。重复旋涂-热解过程可以消除经由一次旋涂热解带来的气泡;另外在银基底和低氧分压条件下,Bi-2212的成相温度点下移,在790℃保温5 h即可制备出单相Bi-2212薄膜。扫描电镜(SEM)观测表明,薄膜表面均匀平整无裂纹。随着烧结温度的升高,Bi-2201相开始出现并且其衍射峰的强度随烧结温度的升高迅速增加;当烧结温度为850℃时,出现了一种棒状相,能谱(EDS)分析表明该棒状相是一种缺Cu相。

关键词： Bi-2212 超导薄膜银基底化学溶液法

基于磁路的高温超导带材临界电流连续检测方法

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稀有金属材料与工程 2015年第2期44卷 429-432页

作者：邹圣楠顾晨瞿体明韩征和清华大学先进成形制造教育部重点实验室北京100084

介绍了一种基于磁路的连续检测高温超导带材临界电流的方法 ,这种方法具有2个突出优势:(1)从原理上不会受机械振动影响产生噪音,从而可以实现高速、稳定的测量;(2)可以测量带有铁磁性RABi TS基底的高温超导带材。本研究介绍了该方法的... 详细信息

介绍了一种基于磁路的连续检测高温超导带材临界电流的方法 ,这种方法具有2个突出优势:(1)从原理上不会受机械振动影响产生噪音,从而可以实现高速、稳定的测量;(2)可以测量带有铁磁性RABi TS基底的高温超导带材。本研究介绍了该方法的基本原理,并搭建了用于测量千米级高温超导带材的实验装置。并通过对铋系、钇系高温超导带材的检测,验证了本方法的优势。

关键词：高温超导带材临界电流连续测量磁路

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磁约束可控核聚变装置的磁体系统综述

发电技术 2024年第6期45卷 995-1015页

作者：张家龙宋彭瞿体明清华大学机械工程系北京市海淀区100084 清洁高效透平动力装备全国重点实验室(清华大学机械工程系) 北京市海淀区100084

【目的】磁约束可控核聚变方案被视为未来解决全球能源问题的重要途径,作为磁约束聚变装置的核心元件,磁体在产生和维持等离子体稳定状态中起着关键作用。为此,对国内外典型磁约束可控聚变装置的磁体结构和规格进行了综述。【方法】回... 详细信息

【目的】磁约束可控核聚变方案被视为未来解决全球能源问题的重要途径,作为磁约束聚变装置的核心元件,磁体在产生和维持等离子体稳定状态中起着关键作用。为此,对国内外典型磁约束可控聚变装置的磁体结构和规格进行了综述。【方法】回顾了聚变磁体从铜基到低温超导乃至高温超导的技术演变,系统归纳了各类典型聚变装置的磁体系统结构及其性能参数。同时,探讨了当前磁体研发过程中面临的技术挑战,并对未来发展进行了展望。【结论】磁体技术的进步对于提升聚变装置性能和加速实现聚变能源的商业化至关重要。随着高温超导材料的应用和新型磁体设计的不断优化,聚变能源的实用化正逐步向现实迈进。

关键词：可控核聚变高温超导材料新能源聚变能源磁约束聚变托卡马克聚变磁体超导体

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A Review of the Ion Beam Assisted Deposition Researches towards Industrialization for the Second Generation High Temperature Superconducting Wire Fabrication

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A Review of the Ion Beam Assisted Deposition Researches towa...

银线表面浸涂法制备Bi_2Sr_2Ca_1Cu_2O_x超导膜

中国材料大会2012

作者： Feng Feng timing qu Kai Shi Rongxia Huang Wei Wu Yanyi Zhang Shaozhu Xiao Junjun Wei Xiaohao Wang Zhenghe Han Division of Advanced Manufacturing Graduate School at Shenzhen Tsinghua University Applied Superconductivity Research Center Department of Physics Tsinghua University Key Laboratory for Advanced Materials Processing Technology Ministry of Education Department of Mechanical Engineering Tsinghua University

ISBN: (纸本)9783037856079;3037856076

Ion beam assisted deposition （IBAD） is an important technique to fabricate the second generation high temperature superconducting （2G HTS） wires. Among the fabrication routes of 2G HTS long wires, IBAD route achieved the best performance in recent years. IBAD was adopted in this field in 1991 to obtain biaxially textured buffer layers, which helped to deposit high quality YBCO superconducting films on metallic substrates for the first time. Series of experimental and industrial researches on IBAD were carried out by many groups worldwide. And in the researches lasting for over two decades, the focused material for IBAD was changed from Yttria-Stabilized Zirconia （YSZ）, Gd2Zr2O7（GZO） to MgO. In this paper, the research progresses and the main achievements were briefly reviewed.

关键词： High temperature superconductor (HTS) Coated conductor Buffer layer Ion beam assisted deposition (IBAD)

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硅酸盐学报 2006年第9期34卷 1031-1035页

作者：宋洋赵亮李霈瞿体明韩征和黄勇清华大学材料科学与工程系新型陶瓷与精细工艺国家重点实验室清华大学物理系应用超导研究中心北京100084

通过浸涂法在银圆线表面制备了Bi2Sr2Ca1Cu2Ox(Bi–2212)超导厚膜。在热处理过程中,局部熔化温度和固相烧结温度对Bi–2212相的形成起关键作用。表面涂覆的直径为0.5mm银线在液氮温度、0T磁场下临界电流密度可达10000A/cm2。系统研究了... 详细信息

通过浸涂法在银圆线表面制备了Bi2Sr2Ca1Cu2Ox(Bi–2212)超导厚膜。在热处理过程中,局部熔化温度和固相烧结温度对Bi–2212相的形成起关键作用。表面涂覆的直径为0.5mm银线在液氮温度、0T磁场下临界电流密度可达10000A/cm2。系统研究了在不同氧分压下,经不同温度退火处理后样品的临界温度Tc值,结果表明:最优退火温度为760℃,样品的Tc值为96.98K,氧分压越高,样品的Tc值越大。此外,Bi–2212材料在空气中放置具有时间效应,会对Tc产生影响。

关键词：浸涂银线局部熔化温度固相烧结温度后退火临界温度时效