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Achieving ultrahigh strength and ductility in high-entropy alloys via dual precipitation

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Journal of Materials Science & technology 2023年第35期166卷 67-77页

作者： J.M.Guo B.C.Zhou S.Qiu H.J.Kong M.C.Niu J.H.luan t.l.zhang H.Wu Z.B.Jiao Department of Mechanical Engineering Research Institute for Advanced ManufacturingThe Hong Kong Polytechnic UniversityHong KongChina the Hong Kong Polytechnic University Shenzhen Research Institute Shenzhen 518057China Department of Materials Science and Engineering City University of Hong KongHong KongChina State Key laboratory of Powder Metallurgy Central South UniversityChangsha 410083China

the strength-ductility trade-offhas been a longstanding dilemma in metallic *** we report an innovative approach to achieve a high strength-ductility synergy via dual precipitation of sheared and bypassed precipitates.(Ni_(2) Co_(2) FeCr)_(96-x) Al_(4) Nb_(x)(at.%)alloys strengthened by nanoscale l12 particles and laves precipitates were selected as a model for this study,and their precipitate microstructures and mechanical properties were thoroughly *** dual-precipitation-strengthened alloys exhibit a yield strength of more than 1400 MPa,an ultimate tensile strength of over 1800 MPa,and a uniform elon-gation of 18%,thus achieving a high strength-ductility *** analysis reveals that the nanoscale l1_(2) precipitates contribute to the strength via the particle shearing mechanism,whereas the laves phase provides the strengthening through the Orowan bypass *** study of deformation microstruc-tures shows that the l1_(2) precipitates are sheared by stacking faults,which facilitates long-range disloca-tion gliding through the *** a result,deformation induces the formation of hierarchical stacking fault networks and immobile lomer-Cottrell locks,which effectively enhance the work hardening ca-pability and plastic stability,thereby resulting in a high ductility at high strength *** are piled-up against the interface between the laves precipitates and matrix,which increases the work hardening capability at the early stages of plastic deformation but causes stress *** dual precipitation strategy may be useful for many other alloys for achieving superior mechanical properties for technological applications.

关键词： High-entropy alloy Dual precipitation Precipitation strengthening Deformation mechanism

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火星磁层中尾向磁场对O^+离子分布的影响

中国科学（E辑） 2001年第6期31卷 502-507页

作者：史建魁刘振兴 t.l.zhang K.torkar 中国科学院空间科学与应用研究中心北京100080 Space Research Institute Austrian Academy of Sciences

在与地球对比的基础上,采用lB磁场模型,根据由动力学方程求解得到的分布函数,研究了火星磁层中不同尾向磁场条件下来自电离层的O+离子沿磁力线的分布。结果发现火星磁尾区O+离子通量密度受火星与太阳风相互作用而产生的感应型尾向磁场... 详细信息

在与地球对比的基础上,采用lB磁场模型,根据由动力学方程求解得到的分布函数,研究了火星磁层中不同尾向磁场条件下来自电离层的O+离子沿磁力线的分布。结果发现火星磁尾区O+离子通量密度受火星与太阳风相互作用而产生的感应型尾向磁场的影响:（i）火星磁尾O+离子通量密度随尾向磁场的增强而增大,当尾向磁场由5nt增大到20nt时,磁尾2.8Rm（Rm为火星半径）处O+离子通量密度可增大3倍左右;（ii）火星磁尾O+离子通量密度随内禀磁矩的增大而减小,当内禀磁矩增大半个量级时,磁尾2.8Rm处O+离子通量密度可减小到25％左右.根据实际观测得到的O+在不同火星磁层区的数据和本文的理论曲线,推测得火星的内禀磁矩约为2×1017t·cm3,这与美国最新的火星探测飞船MGS观测结果一致.

关键词：火星尾向磁场 O^+离子通量密度内禀磁矩分布函数磁层磁力线

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火星磁层中内禀磁场对O^+离子分布的影响

科学通报 1997年第17期42卷 1850-1853页

作者：史建魁刘振兴 t.l.zhang K.torkar 中国科学院空间科学与应用研究中心北京100080 奥地利科学院空间研究所

目前对火星磁层的观测仅是在某些特定情况下和特殊位置的观测,并无系统的数据;在理论研究方面,仅对火星磁层顶位形进行过一些探讨.火星磁层的结构、磁矩的大小(即内禀磁场)及其在火星磁层中的动力学作用问题,仍然是有争论的,有待于进一... 详细信息

目前对火星磁层的观测仅是在某些特定情况下和特殊位置的观测,并无系统的数据;在理论研究方面,仅对火星磁层顶位形进行过一些探讨.火星磁层的结构、磁矩的大小(即内禀磁场)及其在火星磁层中的动力学作用问题,仍然是有争论的,有待于进一步系统地观测分析和理论研究来确定.观测结果还表明,氧离子是火星磁尾重要的离子成分,其通量密度典型值为 2.5 ×10~7cm^(-2)·s^(-1).

关键词：火星磁层离子分布内禀磁场氧离子

Radial distribution of magnetic field in magnetotail current sheet center:Cluster and tC-1 observations

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Radial distribution of magnetic field in magnetotail current...

中国空间科学学会空间物理学专业委员会第十五届全国日地空间物理学研讨会

作者： Z.J.Rong W.X.Wan C.Shen M.W.Dunlop t.l.zhang CAS Key laboratory of Ionospheric Environment Institute of Geology and GeophysicsChinese Academy of Sciences Beijing National Observatory of Space Environment Institute of Geology and GeophysicsChinese Academy of Sciences State Key laboratory of Space Weather Center for Space Science and Applied ResearchChinese Academy of Sciences Rutherford Appleton laboratory ChiltonDIDCOTOxfordshire OX11 0QXUK CAS Key laboratory of Geospace Environment University of Science and Technology of China Space Research Institute Austrian Academy of SciencesGrazAustria

the radial distribution of magnetic field in magnetotail current sheet(CS)determines the background conditions of plasma distribution and evolution in tail CS,so that it is a key issue for further exploring the triggering location of substorm *** the joint magnetic field data of Cluster-3(Samba)during 2001-2009 and tC-1 during 2004 in the magnetotail current sheets center,the dependence of the radial distribution of magnetic field within the radial distance 6REthe geomagnetic activites and the external solar wind condition is statistically *** main results include:1)the magnetic field strength Bmin and its Bz component are enhaced most greatly as radial distance decreasing down to *** and Bz in the range of 10 REller in the midnight and dusk flank region than that in the dawn reigon which indicates the CS thickness is thinner there,showing a evident dawn-dusk asymmetry.2)the strength of Bmin and Bz in quiet time are generally smaller than that in the active time,which is most evidently for the midnight *** implies that the current sheet is generally thicker in active time.3)the occurrence rate of negative Bz enhances greatly in active time around the midnight and dusk flank region,which implies the tail activites have an evident dawn-dusk asymmetric distrbution.4)the electric current density increases evidently in the inner radial range 9RE1RE in active time.5)towards earth,the By component at both flank regions are more apt to be modulated by the diurnal wobbling of the magnetic dipole axis.6)In the range of 10REthe penetrating efficiency of IMF By increases towards *** correlation efficiency between IMF By and CS By around midnight region is higher than that at both flank regions,which means the CS By at the midnight region is closer related to the IMF By relative to that at both flank *** the inner radial range,i.e.6 REthe CS By has no obvious correlation with IMF By.

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Observations of unusual UlF waves at the Venusians bow shock

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Observations of unusual ULF waves at the Venusians bow shock

中国空间科学学会空间物理学专业委员会第十五届全国日地空间物理学研讨会

作者： l.C.Shan Q.M.lu t.l.zhang X.l.Gao C.Huang M.Y.Wu S.Wang CAS Key lab of Geoscience Environment Department of Geophysics and Planetary ScienceUniversity of Science and Technology of China

the Venusian bow shock is formed due to the interaction between the high-speed solar wind and the ionosphere of the *** the magnetic field measurements from Venus Express(VEX),we first reveal the existence of unusual ultralow frequency(UlF)waves in the both upstream and downstream regions of the Venusian bow shock,and the waves are propagating through the Venusian bow *** waves upstream and downstream of the shock have the same characteristics:the peak frequency(the waves have the maximum amplitude at this frequency)is 0.04.05 Hz and they present left-hand polarization with respect to mean magnetic field in the spacecraft *** waves are observed to be associated with quasi-parallel shocks,and propagating obliquely to the magnetic field with an angle from 15° to 64°.therefore,we conclude that these are magnetosonic waves,which may have relevance to the pickup ions reflected by the shock.

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极尖区电离层离子与地磁活动及太阳风的相关分析

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科学通报 2007年第3期52卷 339-343页

作者：郭建广史建魁 t.l.zhang 刘振兴 A.Fazakerley H.Rème I.Dandouras E.lucek 中国科学院空间天气学国家重点实验室 Space Research Institute Aus-trian Academy of SciencesGrazA-8010 Austria Mullard Space Science laboratory University College LondonHolmbury St.MaryDorking RH5 6NTUK Centred'Etude Spatiale des Rayonnements Toulouse 31028France Imperial College LondonS 272B2UK

对2001～2003年间Cluster星簇穿越极尖区期间观测到的电离层起源的离子(O+离子,He+离子和H+离子)特性进行了统计分析,主要研究了这些离子的数密度与地磁活动以及太阳风动压之间的关系.结果表明:O+离子数密度和地磁活动指数Kp之间存在着... 详细信息

对2001～2003年间Cluster星簇穿越极尖区期间观测到的电离层起源的离子(O+离子,He+离子和H+离子)特性进行了统计分析,主要研究了这些离子的数密度与地磁活动以及太阳风动压之间的关系.结果表明:O+离子数密度和地磁活动指数Kp之间存在着正相关关系,He+离子数密度和地磁活动指数Kp不相关,O+离子和He+离子数密度都和太阳风动压之间存在着显著的正相关关系;H+离子数密度与太阳风动压之间存在着正相关关系,而和地磁活动指数Kp不相关.最后,对这些离子的特性与太阳风动压及地磁活动之间的关系进行了讨论.

关键词：极尖区离子 Kp指数太阳风动压

Statistical study of small-scale magnetic holes in the upstream regime of the Martian bow shock

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Statistical study of small-scale magnetic holes in the upstr...

作者： G.Q.Wang M.Volwerk A.M.Du S.D.Xiao M.Y.Wu Y.Q.Chen t.l.zhang

Small-scale magnetic holes(SSMHs) are frequently observed in the solar wind at 1 AU as well as the terrestrial current sheet and *** kinetic-size structures play an important role in energy dissipation and particle ***,we report the existence of SSMHs in the upstream regime of the Martian bow shock and statistically investigate these SSMHs based on 5-year observations of the Mars Atmosphere and Volatile EvolutioN(MAVEN) spacecraft.A total of 549 SSMHs are found,

关键词： Statistical study of small-scale magnetic holes in the upstream regime of the Martian bow shock

time delay of interplanetary magnetic field penetration into Earth's magnetotail

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Time delay of interplanetary magnetic field penetration into...

中国科学院地质与地球物理研究所2015年度（第15届）学术年会

作者： Z.J.Rong A.t.Y.lui W.X.Wan Y.Y.Yang C.Shen A.A.Petrukovich Y.C.zhang t.l.zhang Y.Wei Key laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of Sciences Beijing National Observatory of Space Environment Institute of Geology and GeophysicsChinese Academy of Sciences Swedish Institute of Space Physics Applied Physics laboratory Johns Hopkins University State Key laboratory of Space Weather Center for Space Science and Applied ResearchChinese Academy of Sciences Space Research Institute Russian Academy of Sciences Space Research Institute Austrian Academy of Sciences

Many previous studies have demonstrated that the interplanetary magnetic field(IMF) can control the magnetospheric *** magnetospheric responses to the external IMF have been assumed for a long *** specific processes by which IMF penetrates into magnetosphere,however,are actually *** this issue will help to accurately interpret the time sequence of magnetospheric activities(e.g.,substorm and tail plasmoids) exerted by *** two carefully selected cases,we found that the penetration of IMF into magnetotail is actually delayed by 1–1.5 h,which significantly lags behind the magnetotail response to the solar wind dynamic *** delayed time appears to vary with different auroral convection intensity,which may suggest that IMF penetration in the magnetotail is controlled considerably by the dayside *** unfavorable cases demonstrate that the penetration lag time is more clearly identified when storm/substorm activities are not involved.

关键词： the penetration of IMF into magnetotail is delayed by 1–1.5 h the delay time strongly depends on the polar convection intensity the penetration efficiency is higher than that reported previously

Method for inferring the axis orientation of cylindrical magnetic flux rope based on single-point measurement

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Method for inferring the axis orientation of cylindrical mag...

中国科学院地质与地球物理研究所2013年度（第13届）学术年会

作者： Z.J.Rong W.X.Wan C.Shen t.l.zhang A.t.Y.lui Yuming Wang M.W.Dunlop Y.C.zhang Q.-G.Zong CAS Key laboratory of Ionospheric Environment Institute of Geology and GeophysicsChinese Academy of Sciences Beijing National Observatory of Space Environment Institute of Geology and GeophysicsChinese Academy of Sciences State Key laboratory of Space Weather Center for Space Science and Applied ResearchChinese Academy of Sciences Key laboratory of Basic Plasma Physics Department of Geophysics and Planetary SciencesUniversity of Science and Technology of China Space Research Institute Austrian Academy of SciencesGrazAustria Applied Physics laboratory Johns Hopkins UniversityLaurelMarylandUSA. Rutherford Appleton laboratory ChiltonDIDCOTOxfordshireUK Department of Geophysics Peking University

[1]We develop a new simple method for inferring the orientation of a magnetic flux rope,which is assumed to be a time-independent cylindrically symmetric structure via the direct single-point analysis of magnetic field *** model tests demonstrate that, for the cylindrical flux rope regardless of whether it is force-free or not,the method can consistently yield the axis orientation of the flux rope with higher accuracy and stability than the minimum variance analysis of the magnetic field and the Grad-Shafranov reconstruction ***,the radial distance to the axis center and the current density can also be estimated *** to two actual flux transfer events observed by the four satellites of the Cluster mission demonstrates that the method is more appropriate to be

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