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Electronic structure and magnetic properties of metastable SmCo_(7) compound

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Science china(Physics,Mechanics & Astronomy) 2005年第3期48卷 325-335页

作者： ZHANG Changwen 1 , LI Hua 1 , DONG Jianmin 1 , WANG Yongjuan 1 , PAN Fengchun 1 , ZHANG Jian 1 , GUO Yongquan 2.& LI Wei 2.1. School of Physics and Microelectronics, Shandong University, Jinan 2.0100, china 2. Institute of functional {2., central iron and steel research Institute, beijing 100081, china School of Physics and Microelectronics Shandong University Jinan China Institute of functional materials Central Iron and Steel Research Institutes Beijing China

The electronic density of states, spin-splittings and atomic magnetic moments of SmCo 7 compound have been studied using spin-polarized MS-Xα method. The results show that a few of electrons are transferred to Sm(5d 0 ) orbital because of orbital hybridization between Sm and Co atoms in the compound. The exchange interactions between 3d and 5d electrons lead to the magnetic coupling between Sm and Co, and therefore, result in the long-range ferromagnetic order inside the SmCo 7 compound. There are negative exchange couplings occurring at some levels, which weakens the strength of average coupling around Co lattice. So, the Curie temperature and Co-moment of SmCo 7 decrease distinctly compared with pure Co. Compared with SmCo 5 compound, the disordered substitution of Co-Co “dumbbell-atom” pairs for Sm changes the local environment of Co lattice, which makes the 2. site bear negative magnetic moment. The strength of hybridization near Fermi level weakens and the free energy of the compound increases obviously. Thus, SmCo 7 is a metastable compound at room temperature. Considering the localization of 4f electrons and a few of 5d electrons arising from the orbital hybridization, the magnetic moment of Sm atom will be 1.61μ B in SmCo 7 compound, which is in agreement with the experimental values of Sm 3+ ion- moment and Sm atom-moment in metals.

关键词： electronic structure, spin polarization, atomic magnetic moment, exchange coupling, Curie temperature.

Manufacture of Raney Ni catalyst with metastable Ni_2.l_3 by high energy milling

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中国有色金属学会会刊：英文版 1999年第3期9卷 562-565页

作者： Teng Ronghou(滕荣厚) 1, Sun Shijie(孙世杰) 1, Liu Silin(刘思林) 1, Liu Xuequan(柳学全) 1, Ma Ruzhang(马如璋) 2.Liu Tao(刘涛) 3 1. functional materials Institute, {2. iron & steel research Institute, beijing 100081, P.R.china 2. Depar 钢铁研究总院功能材料所北京 100081 钢铁研究总院功能材料所北京北京科技大学材料物理系北京 100083 中科院高能物理所北京 100039

The Ni Al alloy containing Cr, Fe additives were prepared as Raney Ni catalyst by high energy milling. The size and surface state of Ni Al alloy powder were studied by particle size analyzer and sanning electron microscopy, the structure was analyzed by XRD and Mssbauer methods. The results showed that after a high energy milling (HEM), the Ni Al alloy transforms to a nano scale NiAl structure with rich Al. By annealing the alloy, a metastable Ni 2.l 3 phase can be obtained.

关键词： Raney nickel catalyst nano crystal high energy milling

Investigation on Variation of Inclusions and Total Oxygen in IF steel After RH Deoxidization

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Journal of iron and steel {2. International 2011年第S2期18卷 347-351页

作者： SHU Hong-fu1,2. LIU Liu1, LIU Xue-hua2. ZHANG Xiao-feng2.(1.central iron and {2. research Institute, beijing 100081, china 2. Technology Centre of Maanshan iron and {2. Co Ltd, Maanshan 2.3000, Anhui, china) Cent iron & steel Res Inst Beijing 100081 Peoples R China Maanshan iron & steel Co Ltd Ctr Technol Maanshan 243000 Anhui Peoples R China

The variational regulation of inclusions and total oxygen in the IF Molten steel during the RH refining process after deoxidization was studied. The results show that the relationship between total oxygen content and time is in accord with the following equation, T.O=2.1.2.e-1.53t+2..49, R2.*** inclusion analysis investigation during RH pure circulation process indicates that the main inclusion of the IF molten steel after 2.minutes from the beginning of deoxidization is cluster inclusions of pure Al2.3 system. After 6 minutes from the aluminum deoxidization, the quantity of inclusion decreases and the inclusion style changes into block inclusions of Al2.3 system with the size of 5μm. In the other hand, some inclusions are of Al2.3-MgO. Complex inclusions of Al2.3-TiOx with the size of below 5μm, and the single particle or cluster complex inclusions with the typical square shape of Al2.3-TiN system are found after 3 minutes from titanium-ferrous alloy added. Then, the content of titanium of complex inclusions of Al2.3-TiOx decreases and the aluminum content rises along with the RH pure circulation time process. That means the inclusions of Al2.3-TiOx is not steady, and it trends to transfer into Al2.3.

关键词： IF steel inclusion RH refining

Microstructure and Mechanical Properties of Martensitic Stainless steel 6Cr15MoV

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Journal of iron and steel {2. International 2012年第3期19卷 56-61页

作者： MA Dang-shen1, CHI Hong-xiao1,2. ZHOU Jian1, YONG Qi-long1,2.(1. Institute for Structural materials, central {2. and steel research Institute, beijing 100081, china 2. Faculty of materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093, Yunnan, china) Institute for Structural materials Central Iron and Steel Research Institute Beijing China Faculty of materials Science and Engineering Kunming University of Science and Technology Kunming Yunnan China

Martensitic stainless steel containing Cr of 12. to 18%（mass percent） are common utilized in quenching and tempering processes for knife and cutlery steel. The properties obtained in these {2. are significantly influ- enced by matrix composition after heat treatment, especially as Cr and C content. Comprehensive considered the hardness and corrosion resistance, a new type martensitic stainless steel 6Crl5MoV has been developed. The effect of heat treatment processes on microstructure and mechanical properties of 6Crl5MoV martensitic stainless steel is emphatically researched. Thermo-Calc software has been carried out to thermodynamic calculation; OM, SEM and TEM have been carried out to microstructure observation; hardness and impact toughness test have been carried out to evaluate the mechanical properties. Results show that the equilibrium carbide in 6Cr15MoV steel is M2. C6 car- bide, and the M2. C6 carbides finely distributed in annealed microstructure. 6Crl5MoV martensitic stainless steel has a wider quenching temperature range, the hardness value of steel 6Cr15MoV can reach to HRC 60.8 to HRC 61.6 when quenched at 1 060 to 1 100 ℃. Finely distributed carbides will exist in quenched microstructure, and effectively inhabit the growth of austenite grain. With the increasing of quenching temperature, the volume fraction of undis- solved carbides will decrease. The excellent comprehensive mechanical properties can be obtained by quenched at 1 060 to 1 100℃ with tempered at 100 to 150 ℃, and it is mainly due to the high carbon martensite and fine grain size. At these temperature ranges, the hardness will retain about HRC 59.2.to HRC 61.6 and the Charpy U-notch impact toughness will retain about 17.3 to 2. J. A lot of M2.C6 carbides precipitated from martensite matrix, at the same time along the boundaries of martensite lathes which leading to the decrease of impact toughness when tempered at 500 to 540 ℃. The MaC precipitants also existed in the martensite mat

关键词： martensitic stainless steel microstructure mechanical property

Study on Transformation of CaO-Al_2._3-SiO_2.MgO System Inclusions in ZG06Cr13Ni4Mo Stainless steel

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Journal of iron and steel {2. International 2011年第S2期18卷 341-346页

作者： LIU Jian-hui1,3, DONG Han1,3, ZHU Rong2. LI Shi-qi2.(1. Institute for Structural materials,central {2. and steel research Institute, beijing 100081,china 2. School of Metallurgical and Ecological Engineering,University of Science and Technology beijing, beijing 100083,china 3. National Engineering research Center of Advanced steel Technology, beijing 100081,china) Cent iron & steel Res Inst Inst Struct Mat Beijing 100081 Peoples R China Natl Engn Res Ctr Adv steel Technol Beijing 100081 Peoples R China Univ Sci & Technol beijing Sch Met & Ecol Engn Beijing 100083 Peoples R China

This paper aims at generally studying on the inclusions of ZGG06Cr13Ni4Mo ultra-low carbon stainless steel used for large scale hydraulic turbine sets. On the basis of analysis the industrial test samples, thermodynamic software FactSage is used to study inclusions transformation process in CaO-SiO2.Al2.3-MgO system while stainless steel is been smelting. The results illustrate the inclusions melting points and plasticity variation law. The reasonable inclusions plasticity controlling area is found out in low melting point. The melting point is up to 12.0℃ While MgO weight concentration is 10% in CaO-SiO2.Al2.3-MgO system, SiO2. Al2.3 and CaO in inclusions are in weight concentration range of 50-70%, 10-2.% and 10-40%, respectively. For purpose of gaining low melting point inclusions, silicon alumina radio in deoxidant should be controlled between 2.5 for ultra-low carbon stainless steel refining in industry.

关键词： ZG06Cr13Ni4Mo stainless steel low melting point inclusion thermodynamic calculation

research progress in non-equilibrium grain-boundary segregation and intergranular embrittlement

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Progress in Natural Science:materials International 2006年第2期16卷 109-119页

作者： XU Tingdong (central iron & {2. research Institute, beijing 100081, china) central iron and {2. research Institute Beijing 100081 China

This paper is a summary of the research progress made by the author in the study of non- equilibrium grain-boundary segregation and intergranular embrittlement during the last 2. years. Some new concepts and new model... 详细信息

关键词： grain-boundaries vacancies segregation embrittlement.

The mathematical model of wetting angle of heterogeneous nucleation

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Science china(Technological Sciences) 2004年第4期47卷 391-397页

作者： HUANG Cheng1, SONG Bo1, MAO Jinghong2.& ZHAO Pei3 1. School of Metallurgical and Ecological Engineering, University of Science and Technology beijing, beijing 100083,{2. 2. School of Material Science, University of Science and Technology beijing, beijing 100083,{2. 3. central iron and steel research Institute, beijing 100081,{2. School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing China School of Material Science University of Science and Technology Beijing Beijing China central iron and {2. research Institute Beijing China

The heterogeneous nucleation has been analyzed in terms of the thermodynamic theory, and the mathematical model of wetting angle of heterogeneous nucleation has been developed based on the dynamic requirements of hetero- and homogeneous nucleation. With the wetting angel model, the wetting angles of different catalysts in liquid iron have been calculated. The result shows that the wetting angle of most catalysts is smaller than 40, and the value of f() is far less than 1. The wetting angles of TiN, TiC and RE2.3 are smaller, while the wetting angle of MnO is bigger among the ordinary nucleation catalysts. The wetting angles calculated by this model are in agreement with the results of other research work.

关键词： heterogeneous nucleation, mathematical model, wetting angle, undercooling.

Synthesis of SiC/Al Co-Continuous Composite by Spontaneous Melt Infiltration

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Journal of materials Science & Technology 2000年第5期16卷 466-470页

作者： Guangwei HAN and Di FENG (central iron & {2. research Institute, beijing 100081, china) central iron and {2. research Institute Beijing 100081 China

Investigation has been made on the process of synthesizing SiC/Al co-continuous composite by spontaneous melt infiltration. It is found that nitrogen atmosphere is an indispensable factor for spontaneous infiltration of melt Al into SiC preform with continuous porosity. The critical temperature for spontaneous infiltration occurrence can be lowered and spontaneous infiltration rate increased by doping a small amount of Mg into the Al alloy. Adding fine SiO2.powders into the ceramic preform can play the similar role as Mg-doping by increasing wetting through the chemical reaction of 3SiO2.4AI=2.l2.3+3Si at the infiltration front. Infiltration rate can also be increased by Si-doping to lower the viscosity of the molten Al alloy. In addition, sufficient Si content in the molten Al is also indispensable to avoid the formation of Al4C in the synthesized composite.

关键词： Co SiC Synthesis of SiC/Al Co-Continuous Composite by Spontaneous Melt Infiltration Al

Effects of Temperature and Disperse Phase of Disordered γ on Strain Hardening Rate of Ni_3Al

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Journal of materials Science & Technology 1995年第6期11卷 403-408页

作者： Guangwei HAN Di FENG and Wujun YE (central iron and {2. research Institute, beijing, 100081, china) central iron and {2. research Inst Beijing China

Investigations have been made on the effects of temperature and fine disperse phase of disordered γ on strain hardening rate of Ni3Al based alloy. The result is found that there exists a peak temperature for the strain hardening rate of Ni3Al based alloy below the peak temperature of its yield strength. Analysis shows that the appearance of the peak temperature of strain hardening rate is caused by both the decreasing of the movability of superdislocations on {111}slip plane and the increasing of the dynamic recovery in Ni3Al with increasing temperature. A Ni3Al based alloy hardened by disperse phase of disordered γ has been obtained by controlling chemical composition and treating processes. The peak temperature of strain hardening rate of this alloy is increased due to the fine disperse phase of disordered γ, which causes the reductions of the movability of the superdislocations and the dynamic recovery in Ni3Al

关键词： OO Al on Strain Hardening Rate of Ni3Al Ni