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EFFECT OF Cr ADDITION ON MICROSTRVCTURES AND MECHANICAL PROPERLIES OF β-NiAl ALLOYS

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Acta Metallurgica Sinica(English Letters) 1999年第2期12卷 173-180页

作者： W.H. Tian S.L. Hu and M. Nemoto(1) department of Materials Physics, university of Science and Technology beijing, beijing 100083, china 2) department of Materials Forming, university of Science and Technology beijing, beijing 100083, china 3) department Univ of Science and Technology Beijing Beijing China

The effect of Cr addition on the microstructures and mechanical properties of NiAl inermetallic alloys containing 4 to 8 mol% Cr has been characterized. It is shown that Cr is not only an efficient soild solution strengthener in NiAl, it is also an efficient precipitation Strengthener by fine dispersion of α-Cr particles. Transmission electron microscope observations have revealed that fine spherical particles of α-Cr appeared homogeneously in the NiAl matrix by aging at temperatures around 1073K after solution annealing at 1563K. The aging behavior was investigated by microhardness measurements and the temperature dependence of the yield stress of NiAl containing α-Cr particles was investigated by compression tests over the tempemture range from 298 to 1173K. NiAl alloys happened appreciably by the precipitation of α-Cr *** bypass the particles during deformation and typical Orowan loops were observed surrounding the α-Cr particles after deformation. Although the dispersion Of α-Cr particles increases the yield strength of NiAl at intermediate temperutre, the strength decreases appreciably at higher temperatures.

关键词： NiAl age-hardening precipitate deformation mechanism microstructure

Geochemical characteristics and tectonic implications of HP-UHP eclogites and blueschists in southwestern Tianshan, china

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Progress in Natural Science:Materials International 2006年第6期16卷 624-632页

作者： AI Yongliang, ZHANG Lifei, LI Xuping and QU Junfeng (MOE Key Laboratory of Orogenic Belt and Crust Evolution, School of Earth and Space Sciences, Peking university, beijing 100871, china School of geosciences and Resources, china university of geosciences, beijing 100083, china) [a]MOE Key Laboratory of Orogenic Belt and Crust Evolution School of Earth and Space Sciences Peking University Beijing China [b]School of geosciences and Resources China University of Geosciences Beijing China

Four rock assemblages in correspondence with two different tectonic settings have been recognized in the NEE-SWW extending HP-UHP metamorphic belt in southwestern Tianshan, northwest china. Eclogite assemblage EC1 is geochemically akin to alkaline within-plate oceanic island basalt (OIB). EC2 shows affinity to enriched mid-oceanic ridge basalt (EMORB). Rare earth element (REE) and other immobile trace element characteristics of blueschist assemblage BS1 resemble those of normal mid-oceanic ridge basalt (NMORB). These three assemblages are likely formed on a seamount setting, and the prevalent presence of carbonate minerals and om-phacite quartzite stripes/gobbets suggests ancient pelagic sediments including marls are probably developed upon the basaltic seamount. Whereas the geochemical characteristics of BS2 assemblage are of volcanic arc basalt-type. The seamount with the pelagic sediments on it is brought into the subduction zone, and volcanic arc basalts formed on the active continental margin and trench sediments are eroded and enwrapped in the subducting mass, they are altogether subjected to high to ultrahigh pressure metamorphism and subsequent exhumation towards surface. The HP-UHP metamorphic belt is thus interpreted as a subduct ion-accretionary complex formed by tectonic juxtaposition and imbrication of seamount, seafloor, trench and volcanic arc sequences during oceanic crust subduction.

关键词： southwestern Tianshan HP-UHP metamorphic belt snbduction-accretion complex trace element geochemistry.

Non-existence of positive solution to a quasilinear elliptic system and blow-up estimates for a reaction-diffusion system

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Communications in Nonlinear Science and Numerical Simulation 2001年第4期6卷 222-226页

作者： Zuodong YANG and Qishao LU department of Applied Mathematics, beijing university of Aeronautics and Astronautics, beijing 100083, china department of Applied Mathematics Beijing University of Aeronautics and Astronautics Beijing 100083 China

The non-existence result for radially nonincreasing positive solutions of the system is implied. By using this non-existence result. blow-up estimates for a class of quasilinear reaction-diffusion systems (non-Newtoni... 详细信息

关键词： blow-up. quasilinear reaction-diffusion system. positive radial solutions existence and non-existence

Calculating Models of Mass Action Concentrations for Ni-Mn and Co-Mn Melts and Optimization of Their Thermodynamic Parameters

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International Journal of Minerals,Metallurgy and Materials 2000年第4期14卷 246-250页

作者： Jian Zhang (Metallurgy School, university of Science and Technology beijing, beijing 100083, china) Metallurgy School University of Science and Technology Beijing Beijing 100083 China

According to phase diagrams, measured activities as well as the coexistence theory of motallic melts structure involving compound formation, the calculating models of mass action concentrations for Ni-Mn and Co-Mn melts are formulated and their thermodynamic parameters are optimized. As a result, the calculated mass action concentrations agree well with the corresponding measured activities, showing that these models can reflect the structural characteristics of both Ni-Mn and Co-Mn melts.

关键词： activity metallic melts coexistence theory mass action concentration

Lithosphere types in North china:Evidence from geology and geophysics

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Science china Earth Sciences 2005年第11期48卷 1809-1827页

作者： QIU Ruizhao1,2, DENG Jinfu3, ZHOU Su3, LI Jinfa4, XIAO Qinghui1,5, WU Zongxu6 & LIU Cui3 1. Institute of geology, Chinese Academy of Geological Sciences, beijing 100037, china 2. Development and Research Center, china Geological Survey, beijing 100037, china 3. china university of geosciences, beijing 100083, china 4. china university of geosciences, Wuhan 430074, china 5. Information Center of Ministry of Land and Resources, beijing 100812, china 6. Institute of geology, State Seismological Bureau, beijing 100029, china 1. Institute of geology Chinese Academy of Geological Sciences 100037 Beijing China 2. Development and Research Center China Geological Survey 100037 Beijing China 3. china university of geosciences 100083 Beijing China 4. china university of geosciences 430074 Wuhan China 5. Information Center of Ministry of Land and Resources 100812 Beijing China 6. Institute of geology State Seismological Bureau 100029 Beijing China

On the basis of the characteristics of geology and geophysics in North china, three types of lithosphere, namely, the cratonic, the orogenic and the rift lithospheres can be classified. In terms of petrological method (based on the information from Precambrian rock assemblages, igneous activities, deep-seated enclaves, etc.) and the relationship between seismic velocity and rock compositions, the crust-mantle petrological and chemical structure models can be set up. Researching results indicate that the geology and geophysics of North china platform bears the similar characteristics in comparison with those of the global typical cratons. The Eerduosi(Ordos) block located in the west of the North china Platform is a remnant of cratonic lithosphere after the North china platform had undergone “activation” in Mesozoic and “reconstruction” in Cenozoic times. The continental crust consists mainly of TTG rock assemblage while the subcontinental lithosphere mantle mainly consists of strongly depleted harzburgite. The craton was finally formed in late Archaean and early Proterozoic, and has been kept in stability up to present; its crustal-mantle petrological structures of lithosphere can be set up as a reference for the study of North china craton and even Sino-Korean craton. In the Mesozoic period, the middle and east areas of North china platform were activated in the Yanshanian orogenic process, the continental crust was reformed by material and heat-transfer of convective mantle and the original crustal TTG component was reconstructed to be granitic crust, and the subcontinental lithosphere man- tle was replaced by the Yanshanian harzburgite-lherzolite. The Yanshan-Taihang Mountains were the remnants of orogenic lithosphere after the rifting in eastern North china in Cenozoic. The present thickness of continental crust and lithosphere in the Yanshan-Taihang Mountains is not equal to their thickness during the Yanshanian orogenic movement because they had undergone the

关键词： lithospheric types,evidence of geology and geophysics,crust-mantle petrological structure,deep process

Prediction and Control of both Wrinkle Limit and Fracture Limiton Cylindrical Cup Deep-drawing(Ⅱ)

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International Journal of Minerals,Metallurgy and Materials 1999年第3期13卷 201-204页

作者： Junxiang Lei Yonglin Kang(department of Mechanical Engineering, Yantai university, Yantai 264005, china)(Material Science and Engineering School, university of Science and Technology beijing, beijing 100083, china) department of Mechanical Engineering Yantai University Yantai 264005 China Material Science and Engineering School University of Science and Technology Beijing Beijing 100083 China

The prediction and control criterion of both the wrinkle limit and fracture limit on the cylindrical cup deep-drawing are given, and the prediction and control diagram of both the wrinkle limit and fracture limit are also given. The results show that it is suitable for no-flange cylindrical cup deep-drawing, narrow-flange cylindrical cup deep-drawing, wide-flange cylindrical cup deep-drawing/expanding compound forming and rigid punch expanding forming.

关键词： cylindrical cup wrinkle limit fracture limit deep-drawing expanding forming compound forming

Calculating Models of Mass Action Concentrations for Fe-P and Cr-P Melts and Optimization of Their Thermodynamic Parameters

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International Journal of Minerals,Metallurgy and Materials 1999年第3期13卷 174-177页

作者： Jian Zhang(Metallurgy School, university of Science and Technology beijing, beijing 100083, china) Metallurgy School University of Science and Technology Beijing Beijing 100083 China

Based on the phase diagrams, reliable reference experimental data and the coexistence theory of metallic melts structure involving compound formation, calculating models of mass action concentrations for Fe-P and Cr-P melts have been formulated. At the same time, some of their thermodynamic parameters have been optimized. The calculated results not only agree well with the measuredvalues, but also obey the mass action law rigorously, this in turn shows that these models can reflect the structural characteristics of corresponding melts.

关键词： activity phase diagram coexistence theory mass action concentration

A Back Look on the Binary Phase Diagrams of Metals from the Mass Action Law and the Coexistence Theory of Metallic Melts

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Journal of university of Science and Technology beijing 2001年第1期8卷 15-19页

作者： Jian Zhang Metallurgy School, university of Science and Technology beijing, beijing 100083, china Univ Sci & Technol beijing Met Sch Beijing 100083 Peoples R China

According to the mass action law and the coexistence theory of metallic melts, the mass action concentrations of Cu-Mg, Bi-Tl and Ni-Al melts involving compound formation have been calculated. The calculated results show that, except the ultimate case of pure element, when two elements are present in the melts, all structural units (atoms and molecules) without exception will be present in the melts, i.e., their concentrations may change from great to small, but they will not vanish into nothing, and only under such conditions, the calculated results both agree with practice and obey the law of mass action. In view of that over considerable wide composition range, the activities of both elements of the three solid binary alloys mentioned above have been measured, this seems in contradiction with the present relevant phase diagrams, in which the structural units are determined by composition range, so the latter needs further investigation and consideration.

关键词： activity phase diagram the mass action law the coexistence theory

A New Three-Dimensional Superstructure in Bafertisite

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Acta Geologica Sinica(English Edition) 2011年第5期85卷 1028-1035页

作者： LI Guowu~*,XIONG Ming,SHI Nicheng and MA Zhesheng Crystal structure laboratory,National Laboratory of Mineral Materials,china university of geosciences (beijing),beijing 100083,china Crystal structure laboratory National Laboratory of Mineral Materials China University of Geosciences (Beijing) Beijing 100083 China *Correspondence: Guowu LI *Correspondence: Corresponding author. E-mail: liguowu@***

A new superstructure was found in bafertisite[(Ba;Na;);(Fe;Mn;Mg;);TiO [(Si;Ti;Al;Cr;);O;](OH;F;Cl;);]from Donghai County,Jiangsu Province,*** occurrence of the superstructure reflections were observed by single crystal diffraction using a SMAR APEX *** a;,b;and c;axis directions revealed extra weak reflection spots of the *** apparent 2a,2b and 2c superstructure is monoclinic with unit cell a=10.6502（15） A,b= 13.7233（19）A,c=21.6897（3）A,α=90°,β=94.698（3）°,γ=90°,space group Cm,Z=*** c;extra weak reflections are ignored,the secondary supercell gave a cell a=10.6548（15）A,b=13.7284（19）A,c = 11.6900（17）A,α=90°,β=112.322（28）°,γ=90°,space group Cm,Z=*** basic subcell was obtained by ignoring all extra weak reflection spots and gave:a=5.3249（17）A,b=6.8669（22）A,c=10.8709（36） A,α=90°,β=94.740（62）°,γ=90°,space P2;/m,Z=*** superstructure has been refined to R = 0.063 for 7805[R;= 0.0266]unique reflections I>2δ（I）.The structure consists of an octahedra（O） sheet sandwiched between two heteropolyhedral（H） *** sheets consist of Ti-octahedra and twin tetrahedral disilicate groups[Si;O;].The O sheet comprises（Fe,Mg）O;*** large Ba cation is located in the interlayer *** refined structure shows Fe,Mg are partly *** shifting of the TiO;octahedron and SiO;tetrahedron sites in the sheet may be a consequence of the superstructure.

关键词： bafertisite superstructure crystal structure layered titanium silicate