检索结果-南通市图书馆

microstructure and mechanical properties of 3D printed ceramics with different vinyl acetate contents

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2021年第11期40卷 3241-3250页

作者： He Li Yong-Sheng Liu Yan-Song Liu Qing-Feng Zeng Jing-Jing Liang Science and Technology on Thermostructural Composite Materials Laboratory Northwestern Polytechnical UniversityXi’an 710072China NPU-SAS Joint Research Center of Advanced Ceramics Northwestern Polytechnical UniversityXi’an 710072China Institute of Metal Research Chinese Academy of SciencesShenyang 110016China

Stereolithography(SL)-based three-dimensional(3D) printing technique is an efficient method for the fabrication of alumina *** alumina slurry is difficult to obtain due to the barrier between hydrophilic alumina and oleophilic *** not only requires that the ceramic slurry possessed low viscosity and uniformity,but also requires that the slurry could complete the photocuring *** this study,vinyl acetate was added in the ceramic slurry as a bridge to connect alumina and resin,and the effects of vinyl acetate content on the microstructure and mechanical properties of the alumina ceramics were systematically *** results showed that the alumina ceramics were composed of three types of particles which included large aggregates,individual particles,and long-columnshaped *** shrinkage,bulk density,and crystallite size of the ceramics increased with the increase in vinyl acetate *** open porosity decreased with the increase in vinyl acetate *** flexural strength of the ceramics first increased and subsequently decreased with the increase in vinyl acetate *** shrinkage in Z direction was much greater than that in X or Y *** on the above results,the optimum vinyl acetate content for alumina slurry was 10 wt%,which resulted in sintered ceramic with the shrinkage of 15.6% in X direction,13.5% in Ydirection,21.9% in Z direction,bulk density of 1.9 g·cm^(-3),open porosity of 50.1%,and flexural strength of 24.4 *** sintered ceramics satisfy the requirement of alumina ceramic cores.

关键词： Stereolithography Alumina ceramics Vinyl acetate microstructure Mechanical properties

microstructure evolution,texture and mechanical properties of a Mg-Gd-Y-Zn-Zr alloy fabricated by cyclic expansion extrusion with an asymmetrical extrusion cavity:The influence of passes and processing route

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2021年第3期9卷 964-982页

作者： Zhaoming Yan Xubin Li Jie Zheng Zhimin Zhang Qiang Wang Kaihua Xu Hongzhi Fan Guanshi Zhang Jiaxuan Zhu Yong Xue School of Materials Science and Engineering North University of ChinaTaiyuan 030051China College of Mechatronics Engineering North University of ChinaTaiyuan 030051China

In the present work,two processing routes(A and B)with 3 CEE-AEC passes are performed on Mg-13 Gd-4 Y-2 Zn-0.4 Zr alloys,and the resultant microstructure evolution,texture analysis and mechanical properties are investigated *** core difference between the two processing routes is the orientation between the expansion and extrusion steps,i.e.,they are parallel to each other for on route A and perpendicular to each other for route *** results show that a remarkable grain refinement is achieved via both processing routes due to dynamic recrystallization(DRX).Fine equiaxed grains are observed in the samples processed with route B with a final size of 3.6±0.4μm compared to the grain size of 4.5±0.5μm with route *** an increasing number of CEE-AEC passes,the overall texture intensity decreases,and the basal texture gradually changes to the mixed texture *** shear deformation introduced by the asymmetrical extrusion cavity promotes a broad angular distribution of the basal planes on routes A and B,leading to an obvious increase in the Schmid factor for the activation of the basal a slip *** tensile test at ambient temperature reveals that the comprehensive mechanical properties are improved,and the conventional mechanical anisotropy of as-received alloys is alleviated by successive CEE-AEC processing,which is mainly derived from the competitive balance relation between the grain refinement and texture modification.

关键词： CEE-AEC Mg-Gd-Y-Zn-Zr microstructure Texture Mechanical properties

microstructure and finite element analysis of hot continuous rolling of doped tungsten rod

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2019年第3期26卷 369-376页

作者： Zheng-jie Shao Hai-po Liu Xiao-chun He Bing Zhou Yang Li Shang-zhou Zhang Meng-jin Li Shu-jun Li School of Nuclear Equipment and Nuclear Engineering Yantai University Weihai Multicrystal Tungsten & Molybdenum Technologies Co. Ltd. Institute of Metal Research Chinese Academy of Sciences

The microstructures of doped tungsten deformed by multi-pass hot continuous rolling were investigated, and the stress and strain fields were simulated by finite element(FE) method. After the continuous rolling, the grains of the tungsten rod were refined, and the microhardness was improved; however, a ring region of abnormal grain growth was present at a distance of about 3/5 R(R is the radius of the rod) from the center of the cross section. FE modeling results showed that the equivalent residual strains were minimum around the region of abnormal grain growth; this was due to the release of strain energy by severe plastic deformation, leading a situation where the migration force of grain boundaries was higher than the pinning force of potassium bubbles. By decreasing the initial rolling temperature and rolling speeds, the inhomogeneity of the equivalent residual stain decreased, improving the microstructure uniformity of the doped tungsten.

关键词： doped tungsten continuous rolling microstructure finite element analysis equivalent residual strain

microstructure evolution of a recycled Al-Fe-Si-Cu alloy processed by tube channel pressing

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2018年第10期25卷 1166-1172页

作者： M.H.Farshidi M.Rifai H.Miyamoto Department of Materials Science and Metallurgical Engineering Ferdowsi University of Mashhad Department of Mechanical Engineering Doshisha University

Although excellent recyclability is one of the advantages of Al alloys, a recycling process can reduce different properties of these alloys by adding coarse AlFeSi particles into the alloys' microstructures. One of the well-known methods for modifying the microstructure of metallic materials is the imposition of severe plastic deformation(SPD). Nevertheless, the microstructure evolutions of recycled Al alloys containing extraordinary fractions of AlFeSi particles during SPD processing have seldom been considered. The aim of the present work is to study the microstructure evolution of a recycled Al–Fe–Si–Cu alloy during SPD processing. For this purpose, tubular specimens of the mentioned alloy were subjected to different numbers of passes of a recently developed SPD process called tube channel pressing(TCP); their microstructures were then studied using different techniques. The results show that coarse AlFeSi particles are fragmented into finer particles after processing by TCP. However, decomposition and dissolution of AlFeSi particles through TCP processing are negligible. In addition, TCP processing results in an increase in hardness of the alloy, which is attributed to the refinement of grains, to an increase of the dislocation density, and to the fragmentation of AlFeSi particles.

关键词： AlFeSi intermetallic particle severe plastic deformation microstructure tube channel pressing

microstructure Selection in Ton Class Ingot of Al_(17)Cr_(10)Fe_(33)Ni_(36)Mo_(2)Ti_(2) Eutectic High Entropy Alloy

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2024年第12期37卷 2008-2018页

作者： Xinbo Shi Yunji Qiu Xiaoyu Bai Yiming Chen Yongqiang Wang Tao Xu Jincheng Wang Junjie Li Zhijun Wang State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an710072China Xi’an Superalloy Technology Co. Ltd.Xi’an710299China Anhui Fukai Special Materials Co. Ltd.Xuancheng245300China

The eutectic high entropy alloys have attracted extensive attention and are considered one of the most promising new metal *** microstructures of large eutectic high entropy alloy ingot with excellent casting performance have been rarely *** this study,we have prepared a ton class eutectic high entropy alloy ingot via vacuum induction melting for the first *** evolution of microstructure and macro-segregation from the edge region to the core of the ingot were also *** was found that there was no significant macro-segregation in ton class eutectic high entropy alloy ingot,and chemical elements were distributed *** coupled growth of the primary phases and eutectic colonies were homogeneously distributed in the ingot,and there is no traditional columnar grain region from the edge region of the ingot to the *** tensile strength of the sample in the R/2 region of the ton class ingot with elongation greater than 10%is 892.3 MPa,showing an excellent comprehensive mechanical *** study exhibits an important guidance for the industrial application of large eutectic high entropy alloy casting ingot.

关键词： Eutectic high entropy alloy Ton class ingot Segregation microstructure Mechanical properties

microstructure and Strength of Brazed Joints of Ti_(3)Al Base Alloy with Cu-P Filler Metal

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2005年第4期21卷 493-498页

作者： Peng HE Jicai FENG Heng ZHOU National Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 15{}001 China

Brazing of Ti3Al alloys with the filler metal Cu-P was carried out at 1173-1273 K for 60-1800 s. When products are brazed, the optimum brazing parameters are as follows： brazing temperature is 1215-1225 K; brazing time is 250-300 s. Four kinds of reaction products were observed during the brazing of Ti3Al alloys with the filler metal Cu-P, i.e., Ti3Al phase with a small quantity of Cu （Ti3Al（Cu）） formed close to the Ti3Al alloy; the TiCu intermetallic compounds layer and the Cu3P intermetallic compounds layer formed between Ti3Al（Cu） and the filler metal, and a Cu-base solid solution formed with the dispersed Cu3P in the middle of the joint. The interracial structure of brazed Ti3Al alloys joints with the filler metal Cu-P is Ti3Al/Ti3Al（Cu）/TiCu/Cu3P/Cu solid solution （Cu3P）/Cu3P/TiCu/Ti3Al（Cu）/Ti3Al, and this structure will not change with brazing time once it forms. The thickness of TiCu＋Cu3P intermetallic compounds increases with brazing time according to a parabolic law. The activation energy Q and the growth velocity/to of reaction layer TiCu＋Cu3P in the brazed joints of Ti3Al alloys with the filler metal Cu-P are 286 kJ/mol and 0.0821 m2/s, respectively, and growth formula was y2=O.O821exp（-34421.59/T）*** control of the growth for the reaction layer TiCu＋Cu3P can influence the final joint strength. The formation of the intermetallic compounds TiCu＋Cu3P results in embrittlement of the joint and poor joint properties. The Cu-P filler metal is not fit for obtaining a high-quality joint of Ti3Al brazed.

关键词： Brazed joints microstructure Ti3Al base alloy

microstructure and electrochemical properties of La0.8-xMMxMg0.2Ni3.1Co0.3Al0.1(x=0,0.1,0.2,0.3)alloys

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2017年第8期36卷 645-650页

作者： Na Zhou Wen-Bo Du Pei-Long Zhang Yong-Guo Zhu Zhao-Hui Wang Ke Liu Shu-Bo Li College of Materials Science and Engineering Beijing University of TechnologyBeijing 100124China Whole Win Materials Science and Technology Co. LtdBeijing 100083China

The present study aims to improve electrochemical properties of the La-Mg-Ni-based hydrogen storage alloys through partial substitution for La by mischmetal（MM）.The La_（0.8-x）MM_xMg_（0.2）Ni_（3.1）Co_（0.3）Al_（0.1）（x=0,0.1,0.2,0.3）alloys were prepared by inductive melting,and their phase structures and electrochemical properties were studied by X-ray diffraction（XRD）,scanning electron microscope（SEM）,energy-dispersive X-ray spectrometry（EDX）and electrochemical *** show that the alloys mainly consist of La_2Ni_7-type phase,La_5Ni_（19）-type phase,LaNi_5-type phase and LaNi_3-type *** addition of MM does not change the phase compositions,while it leads to more uniform phase distribution and obviously promotes the formation of La_2Ni_7-type phase which possesses favorable electrochemical *** studies indicate that the substitution for La by MM could effectively improve the high rate dischargeability（HRD）of the alloy electrode,and the optimal value of HRD_（1500）（HRD at 1500 mA·g^（-1））increases from 40.63%（x=0）to 60.55%（x=0.3）.Although the activation properties of the alloy electrodes keep almost unchanged,both the maximum discharge capacity（C_（max））and the cycling stability are significantly improved by MM addition.

关键词： Hydrogen storage alloy microstructure Discharge capacity High rate dischargeability Cyclingstability

microstructure and mechanical properties of transient liquid phase bonding DD5 single-crystal superalloy to CrCoNi-based medium-entropy alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2022年第1期96卷 140-150页

作者： Shiwei Li Jinglong Li Junmiao Shi Yu Peng Xuan Peng Xianjun Sun Feng Jin Jiangtao Xiong Fusheng Zhang State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China Shaanxi Key Laboratory of Friction Welding Technologies Northwestern Polytechnical UniversityXi’an 710072China

This study focuses on the transient liquid phase(TLP)bonding of DD5 single-crystal superalloy to Cr Co Nibased medium-entropy alloy(MEA)using a BNi-2 filler *** microstructure and mechanical properties of the TLP-bonded DD5/MEA joint were evaluated,and the microstructural evolution mechanism was *** formation of the isothermal solidification zone(ISZ)depended on the diffusion of the melting-point depressants(Si and B elements)from the liquid filler into the DD5 and MEA substrates,as well as the dissolution of the *** diffused along theγchannel of DD5 and reacted to form M_(5)B_(3)boride,herein referred to as the diffusion-affected zone(DAZ I).Similarly,the Cr_(5)B_(3)boride precipitated in the Ni-rich MEA matrix adjacent to the MEA substrate(i.e.,DAZ II).Additionally,a coherent orientation of[0]_(BCY)//[011]_(FCC)and(002)_(BCY)//(200)_(FCC)was detected between M_(5)B_(3)boride with a body-centered tetragonal(BCT)structure and the face-centered cubic(FCC)*** performance of the joint was dominated by the properties of the bonding *** the bonding time increased from 20to 80 min,the athermal solidification zone(including eutectic microstructure)was gradually replaced by the ISZ exhibiting excellent plastic deformation capability,and the shear strength of the joint was *** maximum shear strength(752 MPa)was achieved when the eutectic-free joint was bonded at 1050℃ for 80 *** fracture morphology revealed a mixture mode,indicating the initiation of cracks in the DAZ II,mainly propagating in the ISZ,and passing through the DAZ I.

关键词： microstructure Mechanical properties Transient liquid phase bonding Single-crystal superalloy Medium-entropy alloy

microstructure and mechanical properties of 2219 aluminum alloy VPTIG welds during cyclic thermal treatment

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2022年第10期41卷 3539-3545页

作者： Di-Yao Su Hui-Jin Jin Su-Jun Wu School of Materials Scienceand Engineering Beihang UniversityBeijing 100191China

In this study,the effect of the cyclic thermal treatment(CTT) on the microstructure and mechanical properties of the 2219 Al alloy welds fabricated using variable polarity tungsten inert gas(VPTIG) arc welding method were investigated by optical microscope(OM),transmission electron microscope(TEM),and low-temperature tensile tests,with emphasis on precipitation evolution and property variation in different areas of the *** of the microhardness profile across the weld reveals that there are maximum and minimum hardness values in the heat-affected zone(HAZ) adjacent to the fusion boundary(FB).It is found that the maximum hardness value increases with the temperature cycles of the cyclic thermal treatment due to the formation of GuinierPreston(GP) zones,while the microhardness at other positions remains *** results show that the CCT results in an increase in the yield strength,but a decrease in the ductility of the weld joint.

关键词： 2219 aluminum alloy VPTIG weld microstructure Microhardness