检索结果-南通市图书馆

Tunability of the mechanical properties of(Fe_(50)Mn_(27)Ni_(10)Cr_(13))_(100-x)Mo_(x) high-entropy alloys via secondary phase control

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 2021年第14期73卷 210-217页

作者： Raymond Kwesi Nutor q.P.Cao X.D.wang D.X.Zhang j.Z.jiang International Center for New-Structured Materials(ICNSM) Laboratory of New-Structured MaterialsState Key Laboratory of Silicon Materialsand School of Materials Science and EngineeringZhejiang UniversityHangzhou 310027China State Key Laboratory of Modern Optical Instrumentation Zhejiang UniversityHangzhou 310027China

The single-phase face-centered cubic(fcc)-structured Fe_(50)Mn_(27)Ni_(10)Cr_(13) high entropy alloy(HEA)exhibits good ductility but low strength,which presents a *** Mo-alloying and thermomechanical treatments,we have designed the(Fe_(50)Mn_(27)Ni_(10)Cr_(13))_(100-x)Mo_(x)(x=0-6 at.%)alloy series with a wide range of mechanical *** careful control of secondary phases introduced in the cold-rolled and annealed(Fe_(50)Mn_(27)Ni_(10)Cr_(13))Mo_(2) sample resulted in an enhanced tensile strength from 250 MPa to 665 MPa,still having~25%*** investigations of this alloy revealed the presence of deformation twins,dislocation cells,and ordered bcc na no-pa rticles embedded in the ductile fcc matrix *** observed deformation structures are an indication of succes s ful cooperation between deformation twinning and precipitation strengthening in enhancing the tensile strength at maintained ductility compared to its cast *** work provides insight into the tunability of the mechanical properties of non-equiatomic HEAs via alloying and thermomechanical processing.

关键词： High-entropy alloys Mechanical property TEM

Emissivity Calculations Under DCA-UTA Approximation for NLTE Plasmas

在线全文

学校读者我要写书评

暂无评论

Communications in Computational Physics 2007年第6期2卷 1085-1094页

作者： j.q.Pang Z.q.Wu j.Yan Institute of Applied Physics and Computational Mathematics Laboratory of Computational PhysicsP.O.Box 8009-57Beijing 100088China.

A model is developed to calculate emission spectrum from plasmas in nonlocal-thermodynamic-equilibrium(NLTE).The populations are obtained with a Collisional Radiative Model and the spectrum is calculated with the Unresolved-TransitionArray(UTA)*** present model is applied to the calculation of emissivity from low-,medium-and high-Z *** integrated emissivity and the spectra are compared with those calculated by other theoretical *** general speaking,the present results of the mean charge state and emissivity agree well with some theoretical ones while large differences are found when all the theoretical results are included.

关键词： Non-local-thermodynamic-equilibrium(NLTE) emissivity Unresolved-TransitionArray(UTA).

Universal basis underlying temperature, pressure and size induced dynamical evolution in metallic glass-forming liquids

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2024年第1期33卷 134-142页

作者：张华平范蓓蓓吴佳琦李茂枝 Department of Physics Beijing Key Laboratory of Opto-electronic Functional Materials&Micro-nano DevicesRenmin University of ChinaBeijing 100872China Songshan Lake Materials Laboratory Dongguan 523808China Key Laboratory of quantum State Construction and Manipulation Renmin University of ChinaBeijing 100872China

The dramatic temperature-dependence of liquids dynamics has attracted considerable scientific interests and efforts in the past decades, but the physics of which remains elusive. In addition to temperature, some other parameters, such as pressure, loading and size, can also tune the liquid dynamics and induce glass transition, which makes the situation more complicated. Here, we performed molecular dynamics simulations for Ni_(50)Zr_(50) bulk liquid and nanodroplet to study the dynamics evolution in the complex multivariate phase space, especially along the isotherm with the change of pressure or droplet size. It is found that the short-time Debye–Waller factor universally determines the long-time relaxation dynamics no matter how the temperature, pressure or size changes. The basic correlation even holds at the local atomic scale. This finding provides general understanding of the microscopic mechanism of dynamic arrest and dynamic heterogeneity.

关键词： metallic glass-forming liquids structure relaxation dynamical heterogeneity Debye–Waller factor

青藏高原及其周边三叠纪综合地层、生物群与古地理演化

在线全文

学校读者我要写书评

暂无评论

中国科学：地球科学 2024年第4期54卷 1171-1210页

作者：武桂春纪占胜 Gary GLASH 曾庆高姚建新中国地质科学院地质研究所自然资源部地层与古生物重点实验室北京100037 中国地质科学院自然资源部深地科学与探测技术实验室北京100094 Department of Geology and Environmental Sciences State University of New York-FredoniaFredoniaNY 14063USA 西藏自治区地质矿产勘察开发局拉萨850010

青藏高原三叠纪古生物化石丰富,目前已建立了以菊石、牙形类、双壳类、腕足类和放射虫化石为主的海相生物序列以及以孢粉类化石为主的陆相生物序列,为青藏高原三叠纪年代地层划分对比提供了生物标尺.青藏高原在三叠纪整体处于海洋沉积区... 详细信息

青藏高原三叠纪古生物化石丰富,目前已建立了以菊石、牙形类、双壳类、腕足类和放射虫化石为主的海相生物序列以及以孢粉类化石为主的陆相生物序列,为青藏高原三叠纪年代地层划分对比提供了生物标尺.青藏高原在三叠纪整体处于海洋沉积区,海相三叠系发育,主要沉积类型有滨浅海相碎屑岩、浅海台地相碳酸盐岩、半深海斜坡-深海相碎屑岩、硅质岩、海陆过渡相含煤碎屑岩、滨浅海或陆相火山碎屑岩.青藏高原各个地层区的沉积地层序列在垂向上明显分为4个阶段:(1)早三叠世初期广泛接受海侵,发育台地相碳酸盐岩和滨浅海相碎屑岩沉积;(2)中三叠世拉丁期至晚三叠世卡尼期海侵规模最大,与早三叠世相比,沉积相整体变深,发育半深海斜坡-深海相薄层碳酸盐岩、细碎屑岩、硅质岩沉积,部分地区岩浆活动强烈;(3)晚三叠世诺利期海退,沉积相整体变浅,大面积发育台地相碳酸盐岩沉积和滨浅海碎屑岩沉积,在秦-祁-昆一带多表现为陆相地层沉积或陆相剥蚀区;(4)瑞替期持续海退,发育滨浅海碎屑岩或海陆过渡相含煤碎屑岩沉积.根据沉积地层的横向展布和垂向变化,本文对青藏高原三叠纪的沉积古地理按早三叠世、中三叠世-晚三叠世卡尼期、晚三叠世诺利期和晚三叠世瑞替期4个时期进行了描述.整体上,青藏高原在三叠纪是以印度河-雅鲁藏布江缝合带为拉张中心,沉积相向南、北两侧由深变浅,形成了南部冈瓦纳古陆被动边缘沉积体系和北部欧亚古陆被动大陆边缘沉积体系.班公湖-怒江缝合带与南侧的冈底斯地块(或拉萨地块)和北侧的南羌塘地块在沉积特征上比较一致,不是裂解拉张中心.古生物区系研究同样显示印度河-雅鲁藏布江缝合带在三叠纪时期是一个重要的古生物地理区系分界线,班公湖-怒江缝合带在该时期则不具有古生物地理区系分隔的意义.三叠纪时期是潘吉亚超大陆(Pangea)裂解的高峰期,该事件在青藏高原的主要响应是早、中三叠世沿印度河-雅鲁藏布江缝合带发生伸展裂解.印支运动在青藏高原主要表现为晚三叠世地壳抬升引起的沉积相变,在秦-祁-昆一带表现为海相沉积变为陆相沉积或陆相剥蚀区,而在冈底斯至南羌塘的广大地区,表现为台地相碳酸盐岩变为滨浅海相碎屑岩或海陆过渡相含煤碎屑岩.

关键词：青藏高原三叠系生物地层岩石地层古生物区系沉积古地理

Full-band error control and crack-free surface fabrication techniques for ultra-precision fly cutting of large-aperture KDP crystals

在线全文

学校读者我要写书评

暂无评论

Frontiers of Mechanical Engineering 2017年第2期12卷 193-202页

作者： F. H. ZHANG S. F. wang C. H. AN j. wang q. XU Department of Mechanical Engineering Harbin Institute of TechnologyHarbin 150001 China Chengdu Fine Optical Engineering Research Center Chengdu 610041China

Large-aperture potassium dihydrogen phos- phate （KDP） crystals are widely used in the laser path of inertial confinement fusion （ICF） systems. The most common method of manufacturing half-meter KDP crystals is ultra-precision fly cutting. When processing KDP crystals by ultra-precision fly cutting, the dynamic characteristics of the fly cutting machine and fluctuations in the fly cutting environment are translated into surface errors at different spatial frequency bands. These machin- ing errors should be suppressed effectively to guarantee that KDP crystals meet the full-band machining accuracy specified in the evaluation index. In this study, the anisotropic machinability of KDP crystals and the causes of typical surface errors in ultra-precision fly cutting of the material are investigated. The structures of the fly cutting machine and existing processing parameters are optimized to improve the machined surface quality. The findings are theoretically and practically important in the development of high-energy laser systems in China.

关键词： ultra-precision fly cutting large-aperture KDP crystals spatial frequency processing error

STUDY ON THE SHOCK WAVE CRYSTALLIZATION OF AMORPHOUS ALLOYS BY DSC

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2002年第5期15卷 431-438页

作者： H. Y. Zhao, H. wang, q.j. Liu, j.D. Kan and Z.q. LiuDepartment of Materials Science and Engineering, Yunnan University, Kunming 650091, China Department of Materials Science and Engineering Yunnan University

Shock wave and annealing crystallization of amorphous alloys FeSiB, FeMoSiB and FeCuNbSiB were studied by isothermal and non-isothermal DSC technique. It was found that the shock wave crystallization is very perfect, the fraction crystallized is very close to 100%, though the period of crystallization is very short, only about 10-4-10-6s. Their produced phases differ from the parent phase in structure and composition. The high velocity of the transformation is very difficult to explain by the diffusion theory of solid state phase transition.

关键词： amorphous alloy nano-crystallization shock wave crystalliza-tion

Comparison of microstructure and mechanical behavior of Ti-35Nb manufactured by laser powder bed fusion from elemental powder mixture and prealloyed powder

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10期105卷 1-16页

作者： j.C.wang Y.j.Liu S.X.Liang Y.S.Zhang L.q.wang T.B.Sercombe L.C.Zhang School of Engineering Edith Cowan University270 Joondalup DriveJoondalupPerthWA 6027Australia School of Engineering M050The University of Western Australia35 Stirling HighwayCrawleyPerthWA 6009Australia Northwest Institute for Nonferrous Metal Research Xi’an 710016China State Key Laboratory of Metal Matrix Composites School of Material Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Although different types of powder feedstock are used for additive manufacturing via laser powder bed fusion(L-PBF),limited work has attempted to directly compare the microstructure and mechanical behavior of components manufactured from those powder *** work investigated the microstructure,phase composition,melt pool morphology,and mechanical properties of a prealloyed Ti-35Nb alloy manufactured using L-PBF and compared these to their counterparts produced from elemental powder *** samples manufactured from the powder mixture are composed of randomly distributed undissolved Nb in theα/βmatrix,resulting from the unstable melt pool during the melting of the powder *** contrast,parts produced from prealloyed powder display a homogeneous microstructure withβandαphases,owing to the full melting of prealloyed powder,therefore,a more stable melt pool to achieve a homogeneous *** Ti-35Nb manufactured from prealloyed powder exhibits large tensile ductility(about 10 times that of the counterparts using mixed powder),attributed to the high homogeneity in microstructure and chemical composition,strong interface bonding,relatively low oxygen content,and the existence of a large amount ofβ*** work sheds insights into understanding the effect of powder feedstock on the melt pool stability therefore the microstructure and mechanical behavior of the resultant parts.

关键词： Titanium-niobium Powder bed fusion Additive manufacturing Melt pool stability Microstructure Mechanical properties

Effect of water injection on the cavitation control:experiments on a NACA66(MOD)hydrofoil

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2020年第5期36卷 999-1017,I0001页

作者： W.wang T.Tang q.D.Zhang X.F.wang Z.Y.An T.H.Tong Z.j.Li School of Energy and Power Engineering Dalian University of TechnologyDalian 116024China Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of EducationDalian University of TechnologyDalian 116024China

The objective of this work is to investigate experimentally controlling cavitating flow over NACA66(MOD)hydrofoils by means of an active water injection along its suction *** continuous water vertically jets out of the chamber inside the hydrofoil through evenly distributed surface *** were carried out in cavitation water *** high-speed visualization technology and the particle image velocimetry(PIV)system to study the sheetlcloud cavity *** studied the effects of this active control on cavity evolution with four kinds of jet flow at two different jet *** analyzed the effect of water injection on the mechanism of the cavitating flow *** results were all compared with that for the original hydrofoil without jet and show that the active jet can effectively suppress the sheet/cloud cavitation characterized by shrinking the attached cavity size and breaking the large-scaled cloud sheding vortex cavity into small-scaled *** optimum effectiveness of cavitation suppression is affected by the jet flow rates and jet *** water injection at flow rate coefficient 0.0245 with the jet position of 0.45C reduces the maximum sheet cavity length by 79.4%and the cavity shedding is diminished completely,which gives the most superior effect of sheet cavitation *** jet blocks the re-entrant jet moving upstream and weakens the power of re-entrant jet and thus restrains the cavitation development effectively and stabilizes the flow field.

关键词： Cavitation active control Sheet/cloud cavitation.Water injection Re-entrant jet

Effect of grain size on fatigue cracking at twin boundaries in a CoCrFeMnNi high-entropy alloy

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 2020年第4期39卷 1-6页

作者： A.G.wang X.H.An j.Gu X.G.wang L.L.Li W.L.Li M.Song q.q.Duan Z.F.Zhang X.Z.Liao School of Aerospace Mechanical&Mechatronic EngineeringThe University of Sydne0ySydneyAustralia State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China Materials Fatigue and Fracture Division Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Max-Planck-Institut für Eisenforschung Max-Planck-Stra?e 140237 DüsseldorfGermany

The fatigue cracking behavior at twin boundaries(TBs)in a Co Cr Fe Mn Ni high-entropy alloy with three different grain sizes was systematically investigated under low-cycle *** of grain size,the change from slip band cracking to TB cracking occurred with increasing the difference in the Schmid factors(DSF)between matrix and ***,the required critical DSF for the transition of the dominant cracking mode decreases with decreasing grain size due to the reduced slip band spacing that increases the impingement sites on the TBs and facilitates the coalescence of defects and voids to initiate TB cracks.

关键词： High-entropy alloy Fatigue cracking Twin boundary Slip band Grain size