Superconductivity最新文献

{"title":"Short circuit analysis of a fault-tolerant current-limiting high temperature superconducting transformer in a power system in presence of distributed generations","authors":"Alireza Sadeghi,&nbsp;Shahin Alipour Bonab,&nbsp;Wenjuan Song,&nbsp;Mohammad Yazdani-Asrami","doi":"10.1016/j.supcon.2024.100085","DOIUrl":"https://doi.org/10.1016/j.supcon.2024.100085","url":null,"abstract":"<div><p>Power transformers are key elements for the safe and reliable delivery of electrical energy generated by renewable energy resources to consumers via transmission lines. Fault-tolerant current-limiting High Temperature Superconducting (FTCL HTS) transformers are type of superconducting transformers that tolerate fault for seconds and limit the fault current without the threat of burnout or delamination of tapes and deformation of windings. In this paper, the fault performance of a FTCL HTS transformer in a standard IEEE power system is investigated. The studied transformer is a 50 MVA 132 kV/13.8 kV transformer where both windings are made up of HTS tapes. The understudied power system consists of two microgrids with distributed generators. Part of the power in microgrids is supplied by the upstream grid which is connected to the microgrids through the HTS transformers. Two fault scenarios have been considered in this power system, in each one of these scenarios, a fault happens in one of the microgrids. Two considered fault scenarios have an approximate fault current of 18x to 23x of the rated current in the secondary windings. Results showed that insulated windings in FTCL HTS transformers could substantially reduce the peak temperature of the HTS windings, compared to bare windings. Afterwards, post-fault loading is imposed on the HTS windings, to observe their performance against the current increase after fault clearance. In this case, for the first scenario of the faults, the FTCL HTS transformer could tolerate 192% of post-fault overloading, while this number for the second fault scenario is 170%. Finally, the impact of post-fault loading on the full recovery time was discussed.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"9 ","pages":"Article 100085"},"PeriodicalIF":0.0,"publicationDate":"2024-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772830724000024/pdfft?md5=0739bbd85ac438df78e7d50904a2bc05&pid=1-s2.0-S2772830724000024-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139744291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Method with reliable accuracy and fast speed for measuring operational current of HTS NI closed-loop coils in steady persistent-current-mode","authors":"Li Lu ,&nbsp;Wei Wu ,&nbsp;Xin Yu ,&nbsp;Zhuoyan Zhong ,&nbsp;Kai Li ,&nbsp;Chengyun Pan ,&nbsp;Mengzhu Li ,&nbsp;Zhijian Jin","doi":"10.1016/j.supcon.2024.100084","DOIUrl":"10.1016/j.supcon.2024.100084","url":null,"abstract":"<div><p>This study proposes a method for measuring the operational current of high temperature superconducting (HTS) non-insulation (NI) closed-loop coils, which operate in the steady persistent-current-mode (PCM). HTS NI closed-loop coils are promising for many easily-quenching direct-current (DC) applications, where their performance is determined by magnetomotive forces, total number of turns, and dimensions. As the primary interface parameter in an application system, the operational current must be accurately and rapidly measured. Generally, this is achieved by dividing the measured magnetic field by the coil constant. However, even if the influence of the screening current induced field (SCIF) is not considered, existing methods for the coil constant may be disturbed by the performance and location of Hall sensors, or experience a long measuring period. Therefore, a relatively accurate and fast method is proposed in this study, which is based on adjusting the output current of the adjustable power supply and monitoring the coil voltage as an indicator. The proposed method was validated through experiments and simulations using an equivalent circuit model coupled with a finite element method (FEM) model, and its current accuracy can be equivalent to the resolution of the employed power supply. It was demonstrated that this method reduced the requirements for Hall sensor’s performance and location, and has a more reliable accuracy in contrast to the simulation method. Compared to the experimentally conventional method, the proposed method presents a significantly faster speed. The impact of the SCIF was considered and proven to be negligible for the tested pancake coils. Even for coils whose coil constant vibrates owing to the SCIF, this method can be adapted to directly measure various operational currents. Furthermore, it was demonstrated that the measurement error can be influenced by the current discrepancy among turns when the coil is not in the steady PCM, and a procedure for reducing this error was proposed.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"9 ","pages":"Article 100084"},"PeriodicalIF":0.0,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772830724000012/pdfft?md5=757d78df261995052a2978d6aeb0bdcc&pid=1-s2.0-S2772830724000012-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139394828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"40-meter-long REBCO tapes with critical current over 4,000 A/12 mm at 4.2 K and 13 T by advanced MOCVD","authors":"Mahesh Paidpilli ,&nbsp;Chirag Goel ,&nbsp;Bhabesh Sarangi ,&nbsp;Siwei Chen ,&nbsp;Eduard Galstyan ,&nbsp;Jan Jaroszynski ,&nbsp;Griffin Bradford ,&nbsp;Dmytro Abraimov ,&nbsp;Venkat Selvamanickam","doi":"10.1016/j.supcon.2023.100081","DOIUrl":"10.1016/j.supcon.2023.100081","url":null,"abstract":"<div><p>REBa₂Cu₃O_7−δ (REBCO, RE = rare earth) tapes doped with 5% and 15% Zr have been scaled up to lengths more than 40 m in a pilot-scale advanced metal organic chemical vapor deposition (A-MOCVD) tool<em>.</em> The precursor compositions used for the long tapes were guided by a study of the influence of (Ba + dopant)/Cu content on the critical current density (<em>J_c</em>) of 5 and 15 mol.% Hf- and Zr-added tapes at 4.2 K and 13 T. The 40-m-long tapes exhibited a critical current (<em>I_c</em>) over 4,000 A/12 mm at 4.2 K and 13 T as well as over 1,400 A/12 mm at 20 K and 20 T. The critical current densities of a 40-m-long tape doped with 5% Zr at 4.2 K measured at the National High Magnetic Field Laboratory (NHMFL) were &gt; 10 MAcm⁻² and &gt;5 MAcm⁻² at 14 T and 30 T, respectively, which are over three times those of commercial REBCO tapes. The infield <em>J_c</em> of 5% Zr-added 40-m-long tapes was similar to those of previously-reported high-performance short samples made with 15% Zr or Hf. These results demonstrate the excellent potential of A-MOCVD for manufacturing high <em>I_c</em> REBCO tapes for use in ultrahigh-field magnet applications.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"9 ","pages":"Article 100081"},"PeriodicalIF":0.0,"publicationDate":"2023-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772830723000467/pdfft?md5=68567b29316d49e6d356ab3cbd87f05b&pid=1-s2.0-S2772830723000467-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139018265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Review on the state-of-the-art and challenges in the MgB2 component manufacturing for superconducting applications","authors":"Fabiano Carvalho de Castro Sene","doi":"10.1016/j.supcon.2023.100083","DOIUrl":"10.1016/j.supcon.2023.100083","url":null,"abstract":"<div><p>Since the discovery of MgB₂ as a superconductor, several research groups worldwide have studied the superconducting mechanisms due to the dual gap nature of MgB₂, as well as attempted to produce such a compound in wires, tapes, bulks, and thin films for a plethora of applications. While MgB₂ carries the promise of replacing Niobium-based superconductors in low-field applications, less-than-desirable performance and in-operation stability has slowed down such a progress. While the properties and nature of the superconductivity of MgB₂ are fairly known, the reproduction of its properties at manufacturing scales remains an unsolved problem. Therefore, this manuscript presents a systematic review on fundamental properties, phase formation, growth kinetics, and superconducting properties of MgB₂-based components such as multi- and mono-core wires, bulks, and thin films. Advances, challenges, and shortcomings are utilized in consolidating research questions and directions pertaining to the manufacturing of MgB₂ superconducting devices. Lastly, we evaluate the technological readiness of MgB₂-based devices for applications in fusion energy systems.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"9 ","pages":"Article 100083"},"PeriodicalIF":0.0,"publicationDate":"2023-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772830723000480/pdfft?md5=fc76e82b2c42ae3bc236ba7e3682f3fb&pid=1-s2.0-S2772830723000480-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139018297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Screening-current-induced magnetic fields and strains in a compact REBCO coil in self field and background field","authors":"Yufan Yan ,&nbsp;Donghui Jiang ,&nbsp;Peng Song ,&nbsp;Jeonghwan Park ,&nbsp;Seungyong Hahn ,&nbsp;Yunfei Tan ,&nbsp;Timing Qu","doi":"10.1016/j.supcon.2023.100082","DOIUrl":"10.1016/j.supcon.2023.100082","url":null,"abstract":"<div><p>REBa₂Cu₃O₇₋<em>_x</em> (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 applications. Despite 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 layer. In this paper, we report a comprehensive study on the behaviors of screening currents in a compact REBCO coil, specifically the screening-current-induced magnetic fields and strains. Experiments were carried out in the self-generated magnetic field and a background field, respectively. In 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. In 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. Ultimately, a total center field of 32.58 T was achieved before quench. Both the sequential model and the coupled model considering the perpendicular field modification due to conductor deformation are applied. The comparative study shows that, for this coil, the electromagnetic–mechanical coupling plays a trivial role in self-field conditions up to 9 T. In contrast, with a high axial field dominated by the background field, the coupling effect has a stronger influence on the predicted current and strain distributions. Further discussions regarding the role of background field on the strains in the insert suggest potential design strategies to maximize the total center field.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"9 ","pages":"Article 100082"},"PeriodicalIF":0.0,"publicationDate":"2023-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772830723000479/pdfft?md5=aa18d1d395434a3c0a7d6967e6ce67f7&pid=1-s2.0-S2772830723000479-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139014596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Superfluid density dominated junction resistance of bulk polycrystalline YBa2Cu3O7−δ and DyBa2Cu3O7−δ superconductors at low temperature","authors":"Doyel Rakshit,&nbsp;Sourav Das,&nbsp;Ajay Kumar Ghosh","doi":"10.1016/j.supcon.2023.100070","DOIUrl":"10.1016/j.supcon.2023.100070","url":null,"abstract":"<div><p>Resistances of grain junctions of bulk polycrystalline YBa₂Cu₃O_{7−<em>δ</em>} (YBCO) and DyBa₂Cu₃O_{7−<em>δ</em>} (DyBCO) superconductors have been extracted following (i) Ambegaokar- Baratoff (AB) and (ii) de Gennes (dG) equations. Current–voltage (<em>IV</em>) below the critical temperature (<span><math><mrow><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub></mrow></math></span>) has been used to extract transport critical current density (<span><math><mrow><msub><mrow><mi>J</mi></mrow><mrow><mi>c</mi></mrow></msub></mrow></math></span>). The variations of the junction resistances, (<span><math><mrow><msub><mrow><mi>R</mi></mrow><mrow><mi>N</mi></mrow></msub></mrow></math></span>) with temperature (<em>T</em>) exhibit that below a critical value of the normalised superfluid density (NSD), junctions become very low resistive and exhibit metallicity. Dependence of this feature of <span><math><mrow><msub><mrow><mi>R</mi></mrow><mrow><mi>N</mi></mrow></msub></mrow></math></span> on the energy gaps has also been explored. Weak scattering limit is found to be compatible with the maximum of <span><math><mrow><msub><mrow><mi>R</mi></mrow><mrow><mi>N</mi></mrow></msub></mrow></math></span> (<em>T</em>) as is observed from the corresponding NSD.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"8 ","pages":"Article 100070"},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772830723000352/pdfft?md5=5963ffa6ba26b554a9398b52332dbed2&pid=1-s2.0-S2772830723000352-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135763592","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ic measurement of twisted multifilamentary MgB2 wires with non-magnetic sheath over a wide range of temperatures and fields","authors":"Yukai Qiao ,&nbsp;Matt Rindfleisch ,&nbsp;Mike Tomsic ,&nbsp;Michael D. Sumption ,&nbsp;Naoyuki Amemiya ,&nbsp;Rodney A. Badcock ,&nbsp;Nicholas M. Strickland ,&nbsp;Zhenan Jiang","doi":"10.1016/j.supcon.2023.100072","DOIUrl":"https://doi.org/10.1016/j.supcon.2023.100072","url":null,"abstract":"<div><p>All-superconducting rotating machines have the potential for meeting the high power density and high efficiency required for electrical aircraft applications. However, very high AC loss encountered in superconducting armature windings could hinder their development. Multifilamentary MgB₂ wires are one of the promising candidates for the stator windings, due to their potentially low AC loss properties with small filament size and twist pitches. As the first step, the dependence of critical current and <em>n</em>-value on magnetic fields and temperatures <em>I</em>_c(<em>B</em>, <em>T</em>) and <em>n</em>(<em>B</em>,<em>T</em>), which are basic input parameters for AC loss simulation, needs to be measured. In this work, we present transport <em>I</em>_c measurements in three non-magnetic multifilamentary MgB₂ wires (MgB₂/Nb/CuNi/CuZn): one large wire with a 0.70 mm diameter and 25 mm twist pitch, and two small wires with a 0.48 mm diameter each and a 10 mm and 30 mm twist pitch respectively. A four-probe direct current method is used to measure <em>I</em>_c of the MgB₂ wires with variations in temperature (15 – 35 K) and magnetic field (0 – 5.5 T). Full <em>I</em>_c data for the small wire with 10 mm twist pitch was obtained, and the <em>n</em>-values were mostly less than 20. While the <em>I</em>_c data for the large wire at low fields was more limited due to heating, the <em>n</em>-values were higher and could be up to around 100. The difference is attributed to the different filament sizes. Experiments also found that there is no significant hysteresis in the transport critical current measured by decreasing or increasing magnetic fields due to the non-magnetic sheaths. This non-hysteretic characteristic is critical for lowering AC loss because the additional losses from magnetic sheaths can be eliminated. From the magnetic-field dependence of critical current density, an empirical expression has been developed that provides suitable extrapolations to lower fields for the large wire.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"8 ","pages":"Article 100072"},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772830723000376/pdfft?md5=cc68c6b516c6da00e4d7150b36de11dd&pid=1-s2.0-S2772830723000376-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138466284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Review of Moiré superconductivity and application of the Roeser-Huber formula","authors":"Michael R. Koblischka,&nbsp;Anjela Koblischka-Veneva","doi":"10.1016/j.supcon.2023.100073","DOIUrl":"https://doi.org/10.1016/j.supcon.2023.100073","url":null,"abstract":"<div><p>Moiré superconductivity represents a new class of superconducting materials since the discovery of superconductivity in magic-angle (1.1°) twisted bi-layer graphene (MATBG), forming a Moiré lattice with a much bigger crystal parameter as the original lattice constant of graphene. Hence, experimentally changing the Moiré twist angle, 0.93° <span><math><mrow><mo>⩽</mo><mi>Θ</mi><mo>⩽</mo></mrow></math></span>1.27, leads to a variation of the superconducting properties and enables a new way of engineering 2D superconducting materials. Details of the robust superconducting state of MATBG as function of charge carrier density, temperature and applied magnetic fields are reviewed. The influence of the top/bottom hexagonal boron nitride layer thickness on the superconducting properties of MATBG was also demonstrated in the literature. In all fabricated MATBG devices, changing of the charge carrier density leads to the appearance of insulating, metallic and even ferromagnetic states, which separate several superconducting domes in the phase diagram (longitudinal resistance, <span><math><mrow><msub><mrow><mi>R</mi></mrow><mrow><mi>xx</mi></mrow></msub></mrow></math></span>, as function of temperature <em>T</em> and charge carrier density, <em>n</em>). Further works have considered MATBG combined with WSe₂-layers, twisted bi-layer WSe₂, magic-angle tri-layer graphene (MATTG), and most recently, four-layer (MAT4G) and five-layer (MAT5G) stacks. The differences between the layered, cuprate high-<span><math><mrow><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub></mrow></math></span> superconductors and the Moiré superconductors are compiled together. The collected information is then used to apply the Roeser-Huber formalism to Moiré-type superconductivity to calculate the superconducting transition temperature, <span><math><mrow><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub></mrow></math></span>, using only information of the Moiré lattice and the electronic configuration. To account for the different charge carrier densities in the experimental data sets and the low charge carrier mass demands that a new parameter <span><math><mrow><mi>η</mi></mrow></math></span> must be introduced to the Roeser-Huber formalism to enable the description of several superconducting domes found in the phase diagram for a given Moiré angle. Doing so, the calculated data fit well to the correlation curve defined within the Roeser-Huber formalism.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"9 ","pages":"Article 100073"},"PeriodicalIF":0.0,"publicationDate":"2023-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772830723000388/pdfft?md5=942bcaf6ce1556389b23f365592e4178&pid=1-s2.0-S2772830723000388-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138489645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Metallographic investigation of first full-size high-Jc Nb3Sn cable-in-conduit conductor after cyclic loading tests","authors":"Chao Dai ,&nbsp;Yunhao Liu ,&nbsp;Zichuan Guo ,&nbsp;Yu Wu ,&nbsp;Arend Nijhuis ,&nbsp;Tianjun Xue ,&nbsp;Zuojiafeng Wu ,&nbsp;Jinggang Qin","doi":"10.1016/j.supcon.2023.100071","DOIUrl":"https://doi.org/10.1016/j.supcon.2023.100071","url":null,"abstract":"<div><p>In order to verify the feasibility of applying high-J_c Nb₃Sn strand in fusion magnet, a full-size cable-in-conduit conductor (CICC) with short twist pitch (STP) cable pattern was manufactured and tested in SULTAN facility at SPC, Switzerland. Three levels of cyclic electromagnetic (EM) load were applied on the sample stepwise, no visible decrease of current sharing temperature (<span><math><mrow><msub><mi>T</mi><mrow><mi>cs</mi></mrow></msub><mrow><mo>)</mo></mrow></mrow></math></span> was observed until the EM load increased to 80 kA × 10.8 T, after that the <span><math><mrow><msub><mi>T</mi><mrow><mi>cs</mi></mrow></msub></mrow></math></span> decreased dramatically with the EM cycles, which suggested that irreversible deformation, causing a change in the strain state, or even damage has occurred in the superconducting strands. For investigating the reason which caused the conductor performance degradation, the tested conductor was dissected for metallographic observation. Eight segments which subjected to different EM loads were extracted from one of the legs, the geometric feature changes of the cable cross-sections were analyzed and compared. A good correlation was found between the decrease of the <span><math><mrow><msub><mi>T</mi><mrow><mi>cs</mi></mrow></msub></mrow></math></span> and deformation of the cable cross section. A mass of cracks were found on the sub-elements of strands in the segment which subjected to highest EM load, but the amount of crack is much lower in other segments. Combining the analyses, it is speculated that the critical EM load which causes irreversible degradation is between 850 kN/m and 870 kN/m for this conductor. The results could be a reference in high-J_c Nb₃Sn CICC design.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"9 ","pages":"Article 100071"},"PeriodicalIF":0.0,"publicationDate":"2023-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772830723000364/pdfft?md5=dea17fa524a8df5c4f6a6c81c982a7dc&pid=1-s2.0-S2772830723000364-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138549919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental investigation of axial tensile and fatigue behaviors of HTS round strands","authors":"X.Q. Lai,&nbsp;J.X. Zuo,&nbsp;X.B. Hu,&nbsp;T. Zhang,&nbsp;J.D. Liu,&nbsp;P.Y. Li","doi":"10.1016/j.supcon.2023.100069","DOIUrl":"https://doi.org/10.1016/j.supcon.2023.100069","url":null,"abstract":"<div><p>For the development of high-temperature superconducting (HTS) magnet systems of future fusion devices, a novel HTS round strand based on a stacking structure was designed and manufactured using second generation (2G) HTS tapes. Different mechanical loads during operation can result in irreversible degradation of the strand. The axial tension and fatigue loads need particular attention. Therefore, it is important to investigate the electromechanical behavior of the round strand under various axial tension and cyclic loads. In this paper, the axial tensile and fatigue tests were conducted at 77 K, self-field. Taking 95% critical current (<em>I_c</em>) retention as the criterion, the results of the tensile tests revealed that the average tensile stress and strain were as high as 344 MPa and 0.47%, respectively. Fatigue characteristics were also investigated as a function of axial tensile stress. No significant performance degradation was observed up to 100,000 loading cycles with stress amplitudes ranging from 20 MPa to 200 MPa. <em>I_c</em> degradation occurs after 16,000 loading cycles with 380 MPa as the maximum stress. Furthermore, the microscopic defects of the round strand samples due to fabrication imperfections and mechanical loading were investigated using metallographic microscope and scanning electron microscope. These results presented in this paper are useful for comprehending and improving the mechanical behaviors of the strand in high-field and large-scale fusion magnet systems.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"8 ","pages":"Article 100069"},"PeriodicalIF":0.0,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772830723000340/pdfft?md5=22089535b079e26402cfbfd92244a805&pid=1-s2.0-S2772830723000340-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134656497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}