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Evolution of microstructure and properties of a novel Ni-based superalloy during stress relief annealing

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International Journal of Minerals,Metallurgy and Materials 2024年第8期31卷 1876-1889页

作者： lei Jia Heng Cui Shufeng Yang Shaomin lü Xingfei Xie Jinglong Qu Collaborative Innovation Center of Steel Technology University of Science and Technology BeijingBeijing 100083China State Key laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China Beijing GAoNA Materials&Technology Co. Ltd.Beijing 100081China High-Temperature Materials Institute Central Iron and Steel Research InstituteBeijing 100081China

We discussed the decrease in residual stress,precipitation evolution,and mechanical properties of GH4151 alloy in different annealing temperatures,which were studied by the scanning electron microscope(SEM),high-resolution transmission electron microscopy(HRTEM),and electron backscatter diffraction(EBSD).The findings reveal that annealing processing has a significant impact on diminishing residual *** the annealing temperature rose from 950 to 1150℃,the majority of the residual stresses were relieved from 60.1 MPa down to 10.9 ***,the stress relaxation mechanism transitioned from being mainly controlled by dislocation slip to a combination of dislocation slip and grain boundary ***,the annealing treatment promotes the decomposition of the laves,accompanied by the precipitation ofμ-(Mo_(6)Co_(7))starting at 950℃ and reaching a maximum value at 1050℃.The tensile strength and plasticity of the annealing alloy at 1150℃ reached the maximum(1394 MPa,56.1%)which was 131%,200%fold than those of the as-cast alloy(1060 MPa,26.6%),but the oxidation process in the alloy was accelerated at 1150℃.The enhancement in durability and flexibility is primarily due to the dissolution of the brittle phase,along with the shape and dispersal of theγ′phase.

关键词： GH4151 alloy annealing treatment residual stress precipitation evolution strength mechanical properties

Effect of Al_(2)o_(3)on the Mechanical Properties of(B_(4)C+Al_(2)o_(3))/Al Neutron Absorbing Materials

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Acta Metallurgica Sinica(English letters) 2024年第8期37卷 1411-1420页

作者： J.X.Cai B.M.Shi N.li Y.liu Z.G.Zhang Y.N.Zan Q.Z.Wang B.l.Xiao Z.Y.Ma Shi‑Changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Key laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Nuclear Equipment Division Beijing Institute of Nuclear EngineeringChina Nuclear Power Engineering Co.Ltd.Beijing 100840China Department of Materials Science School of Mechanical EngineeringShenyang UniversityShenyang 110044China

B_(4)C/Al composites are widely utilized as neutron absorbing materials for the storage and transportation of spent nuclear *** order to improve the high-temperature mechanical properties of B_(4)C/Al composites,in-situ nano-Al_(2)o_(3)was introduced utilizing oxide on Al powder *** this study,the Al_(2)o_(3)content was adjusted by utilizing spheroid Al powder with varying diameters,thereby investigating the impact of Al_(2)o_(3)content on the tensile properties of(B_(4)C+Al_(2)o_(3))/Al *** was found that the pinning effect of Al_(2)o_(3)on the grain boundaries could hinder the recovery of dislocations and lead to dislocation accumulation at high *** the result,with the increase in Al_(2)o_(3)content and the decrease in grain size,the high-temperature strength of the composites increased *** finest Al powder used in this investigation had a diameter of 1.4μm,whereas the resultant composite exhibited a maximum strength of 251 MPa at room temperature and 133 MPa at 350℃,surpassing that of traditional B_(4)C/Al composites.

关键词： Al matrix composites Neutron absorbing materials (B_(4)C+Al_(2)o_(3))/Al composites High-temperature strength

Relationship between the severity of hepatitis C virus-related liver disease and the presence of Helicobacter species in the liver: A prospective study

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World Journal of Gastroenterology 2006年第45期12卷 7278-7284页

作者： laurent castéra Anne Pedeboscq Marcia Rocha Brigitte le Bail Corinne Asencio Victor de lédinghen Pierre-Henri Bernard Christophe laurent Marie-Edith lafon Maylis Capdepont Patrice Couzigou Paulette Bioulac-Sage Charles Balabaud FrancisMégraud Armelle Ménard Service d'Hépato-Gastroentérologie H?pital St-André Bordeaux France Service d'Hépato-Gastroentérologie H?pital Haut Lévêque Pessac France INSERM ERI 10 Laboratoire deBactériologie Université Victor Segalen Bordeaux 2 BordeauxFrance INSERM E0362Groupe de Recherche pour l'étude du Foie Université VictorSegalen Bordeaux 2 Bordeaux France Service d'Anatomie Pathologique H?pital Pellegrin Bordeaux France Service de ChirurgieDigestive H?pital St-André Bordeaux France laboratoire de Virologie Université VictorSegalen Bordeaux 2 Bordeaux France

AIM: To determine the presence of Helicobacter species DNA in the liver of chronic hepatitis C (CHC) patients with and without cirrhosis as compared to controls, and to identify the bacterial species involved. METHoDS: Seventy-nine consecutive patients (HBV and HIV negative) with a liver sample obtained after liver biopsy or hepatic resection were studied: 41 with CHC without cirrhosis, 12 with CHC and cirrhosis, and 26 controls (HCV negative). Polymerase chain reactions (PCRs) targeting Helicobacter 16S rDNA and species- specific were performed on DNA extracted from the liver. A gastric infection with H pylori was determined by serology and confirmed by 13C-urea breath test. RESUlTS: overall, Helicobacter 16S rDNA was found in 16 patients (20.2%). Although positive cases tended to be higher in CHC patients with cirrhosis (41.6%) than in those without cirrhosis (17.0%) or in controls (15.4%), the difference was not statistically significant (P =0.08). H pylori-like DNA was identified in 12 cases and H. pullorum DNA in 2, while 2 cases remained unidenti- fied. Gastric infection with H pylori was found in only 2 of these patients. CoNClUSIoN: our results do not confirm the associ- ation of Helicobacter species DNA in the liver of CHC patients with advanced liver disease. The lack of correlation between positive H pylori serology and the presence of H pylori-like DNA in the liver may indicate the presence of a variant of this species.

关键词： Hepatitis C virus Hepatitis Cirrhosis Helicobacter

Sc元素添加对双辊铸轧Al−Cu−li−Mg−Zr基合金热处理的影响

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Transactions of Nonferrous Metals Society of China 2024年第6期34卷 1759-1773页

作者： Rostislav KRÁlÍK Barbora KŘIVSKÁ lucia BAJToŠoVÁ Mykhailo STolBCHENKo Mirko SCHAPER olexandr GRYDIN Miroslav CIESlAR Department of Physics of Materials Faculty of Mathematics and PhysicsCharles UniversityKe Karlovu 512116PragueCzech Republic Department of Materials Science Faculty of Mechanical EngineeringUniversity of PaderbornWarburger Straße 10033098PaderbornGermany

提出制备含Sc的Al−Cu−li−Mg−Zr基合金带材的工艺方案。即先采用双辊铸轧技术制备近净形状的3 mm厚带材,再对其进行均匀化/固溶处理。研究两种Al−Cu−li−Mg−Zr基双辊铸轧合金,其中一种添加质量分数为0.17%的Sc,另一种未添加Sc。两种合金... 详细信息

提出制备含Sc的Al−Cu−li−Mg−Zr基合金带材的工艺方案。即先采用双辊铸轧技术制备近净形状的3 mm厚带材,再对其进行均匀化/固溶处理。研究两种Al−Cu−li−Mg−Zr基双辊铸轧合金,其中一种添加质量分数为0.17%的Sc,另一种未添加Sc。两种合金均先在300℃下退火30 min,然后在450℃下退火30 min以及530℃下退火30 min,随后进行室温水淬。前两段退火后组织中生成了细小、弥散的Al_(3)Zr/Al_(3)(Sc,Zr)颗粒。最后的退火步骤起到了均匀化/固溶处理的作用。双辊铸轧材料的细小晶粒结构使含有主要合金元素的原始颗粒在较短的退火时间内溶解。缩短保温时间可以限制表面层中li的耗尽和Al_(3)Zr/Al_(3)(Sc,Zr)弥散相的明显粗化。铸态含Sc材料已经具有明显细小的晶粒结构,而经均匀化/固溶处理后生成的Al_(3)(Sc,Zr)弥散相抑制了晶粒在高温下发生粗化。在后续180℃下时效处理后,形成了θʹ(Al_(2)Cu)、T1(Al_(2)Culi)和S'(Al_(2)CuMg)强化相。在峰值时效状态下,屈服强度提高了200 MPa,这一数值与类似直接冷却铸造材料的相当,从而证实了所提方案的合理性。

关键词：显微组织力学性能 Al−Cu−li基合金 Sc合金化双辊铸轧

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Single atom Cu-N-C catalysts for the electro-reduction of Co_(2) to Co assessed by rotating ring-disc electrode

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Journal of Energy Chemistry 2024年第1期88卷 169-182,I0004页

作者： S.Pérez-Rodríguez M.Gutiérrez-Roa C.Giménez-Rubio D.Ríos-Ruiz P.Arévalo-Cid M.V.Martínez-Huerta A.Zitolo M.J.lázaro D.Sebastián Instituto de Carboquímica(CSIC) Miguel Luesma Castán 450018 ZaragozaSpain Instituto de Catálisis y Petroleoquímica(CSIC) Marie Curie 228049 MadridSpain Synchrotron SolEIl L’Orme des MerisiersDépartementale 12891190France

The electrochemical Co_(2) reduction reaction(Co_(2)RR) to controllable chemicals is considered as a promising pathway to store intermittent renewable energy. Herein, a set of catalysts based on copper-nitrogendoped carbon xerogel(Cu-N-C) are successfully developed varying the copper amount and the nature of the copper precursor, for the efficient Co_(2)RR. The electrocatalytic performance of Cu-N-C materials is assessed by a rotating ring-disc electrode(RRDE), technique still rarely explored for Co_(2)RR. For comparison, products are also characterized by online gas chromatography in a H-cell. The as-synthesized Cu-NC catalysts are found to be active and highly Co selective at low overpotentials(from -0.6 to -0.8 V ***) in 0.1 M KHCo_(3), while H_(2) from the competitive water reduction appears at larger overpotentials(-0.9 V vs. RHE). The optimum copper acetate-derived catalyst containing Cu-N_(4) moieties exhibits a Co_(2)-to-Co turnover frequency of 997 h^(-1) at -0.9 V vs. RHE with a H_(2)/Co ratio of 1.8. These results demonstrate that RRDE configuration can be used as a feasible approach for identifying electrolysis products from Co_(2)RR.

关键词： Cu-N-C Carbon xerogel Rotating ring disc electrode Carbon dioxide reduction reaction Carbon monoxide

再生细骨料和砖粉双掺对3D打印混凝土性能的影响

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华南理工大学学报（自然科学版） 2024年第3期52卷 18-27页

作者：张海燕马金一吴波吕艳梅华南理工大学土木与交通学院广东广州510640 广东省现代土木工程技术重点实验室广东广州510640 华南农业大学水利与土木工程学院广东广州510642

为减少3D打印混凝土中天然骨料及胶凝材料的用量,本文采用再生混凝土细骨料替代部分天然细骨料,砖粉替代部分水泥,首先开展单掺再生细骨料(取代率为0、25%、50%、75%和100%)、单掺砖粉(取代率为0、5%、10%、15%、20%和30%)和两者双掺的... 详细信息

为减少3D打印混凝土中天然骨料及胶凝材料的用量,本文采用再生混凝土细骨料替代部分天然细骨料,砖粉替代部分水泥,首先开展单掺再生细骨料(取代率为0、25%、50%、75%和100%)、单掺砖粉(取代率为0、5%、10%、15%、20%和30%)和两者双掺的现浇混凝土的流动性和抗压强度试验,以获得再生细骨料和砖粉的适宜取代率;然后探究50%再生细骨料和10%砖粉双掺及配合比调整方式(附加水、提高减水剂用量)对3D打印混凝土拌合物性能及硬化后力学性能的影响。试验结果表明,当再生细骨料的掺量不超过50%时,现浇混凝土抗压强度降低幅度在10%以内;随着砖粉掺量从0增加到30%,现浇混凝土抗压强度总体呈现先增后减、再稍有增加的趋势,当砖粉掺量为10%时,混凝土抗压强度最高;相比于单掺50%再生细骨料的混凝土,50%再生细骨料和10%砖粉双掺时混凝土强度有所增加,而流动性基本不变。对于3D打印混凝土,同时掺入50%再生细骨料和10%砖粉,并采用添加附加水的方式保持3D打印混凝土初始扩展度不变,会使得混凝土的可建造性提高,但坍落度、开放时间、抗压和劈裂抗拉强度降低,强度各向异性加剧;而提高减水剂用量不仅能显著提升3D打印混凝土的流动性能、开放时间和抗压强度,还能降低打印试件的强度各向异性。

关键词： 3D打印混凝土再生细骨料砖粉打印性能硬化性能各向异性

Precipitation analysis of as-cast HK40 steel after isothermal aging

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International Journal of Minerals,Metallurgy and Materials 2017年第10期24卷 1125-1133页

作者： M.l. Saucedo-Munoz A. ortiz-Mariscal V.M. lopez-Hirata J.D. Villegas-Cardenas orlando Soriano-Vargas Erika o. Avila-Davila Instituto Politecnico Nacional (ESIQIE) Apdo. Postal 118-395 Mexico D.F. 07300 Universidad Politecnica Metepec y Tultitlan Edo. Mex. Mexico Tecnológico de Estudios Superiores de Jocotitlan Jocotitlan Edo. Mex. Mexico

As-cast HK40 steel was aged at 700, 800, or 900℃ for times as long as 2000 h. Microstructural characterization showed that the primary M_7C_3 carbide network contained a substantial content of manganese, in agreement with the microsegregation of manganese calculated by Thermo-Calc using the Scheil–Gulliver module. The dissolution of primary carbides caused the solute supersaturation of austenite and subsequent precipitation of fine M_(23)C_6 carbides in the austenite matrix for aged specimens. During prolonged aging, the carbide size increased with increasing time because of the coarsening process. A time–temperature–precipitation diagram for M_(23)C_6 carbides was calculated using the Thermo-CalcPRISMA software; this diagram showed good agreement with the experimental growth kinetics of precipitation. The fine carbide precipitation caused an increase in hardness; however, the coarsening process of carbides promoted a decrease in hardness. Nanoindentation tests of the austenite matrix indicated an increase in ductility with increasing aging time.

关键词： as-cast HK40 steel carbide precipitation aging precipitation simulation

Effect of homogenization process on the hardness of Zn-Al-Cu alloys

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International Journal of Minerals,Metallurgy and Materials 2015年第10期22卷 1076-1081页

作者： Jose D.Villegas-Cardenas Maribel l.Saucedo-Munoz Victor M.lopez-Hirata Antonio De Ita-De la Torre Erika o.Avila-Davila Jorge luis Gonzalez-Velazquez Department of Metallurgy and Materials Instituto Politecnico Nacional(IPN-ESIQIE)Mexico City 07300Mexico Department of Industrial Engineering Universidad Politecnica del Valle de MexicoMexico CityMexico Department of Materials Universidad Autonoma Metropolitana(UAM)Unidad AzcapotzalcoMexico

The effect of a homogenizing treatment on the hardness of as-cast Zn–Al–Cu alloys was investigated. Eight alloy compositions were prepared and homogenized at 350 °C for 180 h, and their Rockwell 'B' hardness was subsequently measured. All the specimens were analyzed by X-ray diffraction and metallographically prepared for observation by optical microscopy and scanning electron microscopy. The results of the present work indicated that the hardness of both alloys(as-cast and homogenized) increased with increasing Al and Cu contents; this increased hardness is likely related to the presence of the θ and τ′ phases. A regression equation was obtained to determine the hardness of the homogenized alloys as a function of their chemical composition and processing parameters, such as homogenization time and temperature, used in their preparation.

关键词： zinc–aluminum–copper alloys casting hardness homogenization phases microstructure

Effect of Deformation on the Mechanical and Electrical Properties of Aluminum-Magnesium Alloy

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Journal of Minerals and Materials Characterization and Engineering 2011年第6期10卷 553-560页

作者： S. o. Adeosun o. I. Sekunowo S.A. Balogun l.o. osoba Department of Metallurgical and Materials Engineering University of Lagos Lagos Nigeria

This paper presents the effect of deformation on the tensile strength, toughness, hardness and electrical resistance of aluminum 6063 alloy. cast samples were cold rolled in the range of 0-24 percent thickness reduction and subjected to mechanical (static, dynamic) and electrical resistance tests. Results show significant improvement in hardness and electrical resistance properties of the alloy. The nature, amount and distribution of the secondary phase, Mg2Si,particles precipitated within the matrix which was influenced by the extent of cold-work, are responsible for the observed behaviour. The resistance of the alloy also depends on the degree of cold work carried out prior to use.

关键词： Cold work tensile strength toughness hardness electrical resistance.