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Fabrication and magnetic properties of Sm_3(Fe,Ti)_(29)N_x/α-Fe dual-phase nanocomposite permanent magnetic material

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Science China(Technological Sciences) 2007年第2期50卷 184-189页

作者： CUI ChunXiang, ZHANG Ying, SUN JiBing & WANG Ru School of Materials Science and Engineering, Hebei University of Technology, tianjin 300130, China School of Materials Science and Engineering Hebei University of Technology Tianjin China

Sm3(Fe,Ti)29Nx/α-Fe dual-phase nanometer magnetic material was fabricated through rapid solidification, crystallization and nitridation of Sm-Fe (Ti) alloy. The effect of combination of rapid solidification and Ti alloy addition on the phase for- mation and microstructure of the Sm-Fe alloy is investigated in this paper. The mi- crostructure of amorphous phase and dual-phase nano-grain crystals before and after crystallization annealing were observed using a high-resolution transmission electron microscope (HREM). The dual-phase nano-grains after annealing were compacted together with a clear interface with the direct exchange-coupling mechanism. Different annealing processes were used to examine the melt-spun alloy. Comparison of the images of SEM showed that annealing at 750 ℃ for 10 min was most suitable to get homogeneous and nano-grains. No obvious kink was de- tected in the second quadrant of the hysteresis loop like a single hard magnet, and strong exchange coupling was found between hard magnets and soft magnets.

关键词： rapid solidification microstructure Sm3(Fe Ti)29Nx/α-Fe dual phase nanocomposite exchange-coupling

Effect of Titanium,Antimony,Cerium and Carbon Nanotubes on the Morphology and Microhardness of Mg-based Icosahedral Quasicrystal Phase

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Journal of Materials Science & Technology 2010年第1期26卷 27-32页

作者： Zhifeng Wang, Weimin Zhao, Haipeng Li, Jian Ding, Yongyan Li and Chunyong Liang School of Materials Science and Engineering, Hebei University of Technology, tianjin 300130, China School of Materials Science and Engineering Hebei University of Technology Tianjin 300130 China

For the first time, petal-like and spherical Mg-based icosahedral quasicrystal phase （I-phase） were obtained by introducing Ti, Sb, Ce and C nanotubes into Mg-Zn-Y alloy under normal casting conditions. The formation mechanism and stability criterion of spherical I-phase were discussed. The morphology and microhardness of I-phase and their determinants were studied in this paper. The results show that the different value of microhardness of I-phase could be attributed to the different kinds of the fourth component and its content, and its different innate characters. The final morphology of icosahedral quasicrystalline （IQC） is decided by the size of critical stable radius Rr, the content of the fourth component and degree of undercooling.

关键词： Quasicrystal Magnesium alloy Morphology Microhardness

Crossed Micro-bands in the Martensite Variant Pairs of a Thermomechanically Trained Cu-Zn-Al Alloy

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Journal of Materials Science & Technology 1995年第6期11卷 418-420页

作者： Qingan ZHANG and Nanju GU (Hebei Institute of Technology tianjin, 300130, China)(East China Institute of Metallurgy,Ma’anshan, 243002, China) Hebei Inst of Technology Tianjin China

The crossed micro-bands in the martensite variant pairs of a thermomechanically trained Cu25.66Zn-4.02Al (wt-%) alloy have been studied. It was found that the micro-bands pass through the interface from one martensite variant to another and their orientation inside different variants is distinct, which would remain in the parent phase after the reverse transformation and play an important role in the formation of preferential martensite. In fact, the crossed micro-bands are micro-twins for accommodating the stress fields generated during thermomechanically training

关键词： Zn Al Crossed Micro-bands in the Martensite Variant Pairs of a Thermomechanically Trained Cu-Zn-Al Alloy Cu

Thermal behavior of B_4 Cparticles under plasma arc powder surfacing condition

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China Welding 1996年第2期5卷 140-145页

作者： WANG Xibao ZHANG Wenyue LU Tongli and PENG Jie(Hebei University of Technoligy,300130.tianjin)(Wenyue.Welding Department,tianjin Universiy,300072,tianjin.)

The effect of plasma arc powder surfacing process on the amount of B4C particles in the coating and the thermal behavior of B4C particles in different surfacing stages has been *** results showed that the feeding rate of B4C partiles is the most important factor affecting the amount of B4C particles in the surfacing coating among all the surfacing parameters,and the most part of B4C Particles in the coating is nto the remainders of original solid B4C particles,but the consolidation products of the unmelted liquid B4C globules in the *** results also showed that the B4C particles would not be melted in the plasma arc column, their melting process mainly takes place in the anode spot region on the surface of the pool when surfacing current is less than 200A.

关键词： B_4C plasma arc powder surfacing thermal behavior

A new contact material—Ag/SnO_2-La_2O_3-Bi_2O_3

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Rare Metals 2002年第4期21卷 289-293页

作者： LU Jianguo, WANG Jingqin, ZHAO Jingying, WEN Ming, WANG Baozhu, and WANG XiaohongInstitute of Electrical Apparatus, Hebei University of Technology, tianjin, 300130, China Institute of Electrical Apparatus Hebei University of Technology 天津 300130 Institute of Electrical Apparatus Hebei University of Technology Tiaojin 300130

A super-fine compound powder, Ag/SnO_2+La_2O_3+ Bi_2O_3, has been obtainedusing the chemical coprecipitation method. And a new contact material, Ag/SnO_2+La_2O_3+Bi_2O_3, wasproduced by the powder metallurgy method. Its properties are as follows: the density is 9.75-9.93g/cm^3, the resistivity is 2.31-2.55 μΩ ·cm, the hardness is 880-985 MPa. Its mi-crostructureshows that the fine oxides have a uniform distribution in the silver matrix. The results ofmake-break capacity and temperature rise testing show that the new material has better ability ofanti-arc erosion and lower temperature rise than that of commonly used Ag/CdO.

关键词： contact material silver rare earth oxide powder metallurgy microstructure additive

A Method on the Item Investment Risk Interval Decision-making of Processing Ranking Style

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Systems Science and Systems Engineering 2002年第3期11卷 333-340页

作者： CHEN Li-wenSchool of management, Hebei University of Technology, tianjin 300130, China School of management Hebei University of Technology Tianjin 300130 China

In this paper, on the bases of the defect of riskful type and indefinite type decisions, the concept of the type of item investment probability scheduling decision is given, and a linear programming model and its solution are made out. The feasibility of probability scheduling type item investment plan is studied by applying the quality of interval arithmetic.

关键词： item investment probability scheduling interval sequence relation multi-dimensional decision

Effect of As Interstitial Diffusionon on the Properties of Undoped Semi-insulating LECGaAs

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Rare Metals 2001年第3期20卷 187-191页

作者： Ruixia Yang, Fuqiang Zhang, Nuofu Chen 1) Hebei University of Technology, tianjin 300130, China 2) Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China 河北工业大学天津 300130 中科院半导体所北京 100083

Annealing was carried out at 950 and 1120 degreesC under various As pressure for undoped (ND) semi-insulating (SI) LECGaAs. The effects of annealing on native defects and electrical properties were investigated. Experimental results indicate that, after an annealing at 950 degreesC for 14 h under low As pressure, the Hall mobility decreases and the resistivity increases dramatically for the samples. These changes in electrical properties are due to the generation of intrinsic acceptor defects, and the generation of the intrinsic acceptor defects originates from the outdiffusion of As interstitial at high temperature. The generation of the intrinsic defects and these changes in electrical properties can be suppressed by increasing the applied As pressure during annealing. The concentration of the main donor defect E12 (AsGaVGa) can be decreased by about one order of magnitude by an evacuated annealing at 1120 degreesC for 2-8 h followed by a fast cooling. The decrease in E12 concentration can also be suppressed by increasing the As pressure during annealing.

关键词： semi-insulating GaAs intrinsic acceptor defects As interstitial indiffusion As pressure annealing

Effect of Al on Microstructures and Mechanical Properties of the Ultrahigh Carbon Steels

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Journal of Materials Science & Technology 2004年第5期20卷 567-570页

作者： Huifen PENG, Baoqi WANG, Jianjun ZHANG, Xiaoyan SONG, Xiaoli MA and Nanju GUSchool of Materials Science & Engineering, Hebei University of Techonology, tianjin 300130, China Sch. of Mat. Sci. and Eng. Hebei Univ. of Technol. Tianjin 300130 China

In this research, we tried to find a simple processing method to break up the network carbides in ultrahigh carbon steels (UHCS). Our results revealed that Al addition was favorable to the decrease in the proeutectoid carbides, the pearlite-colony size and the pearlitic interlamellar spacing of the forged microstructures, and that a fully-pearlitic structure was obtained in the UHCS containing 1.6 wt pct Al. The quenching-and-tempering process resulted in fine microstructure in those steels. On the other hand, the strength of the UHCSs increased with the increase of the Al content, and the highest strength was obtained at the UHCS with 1.6 wt pct Al. The UHCSs with Al contents higher than 1.3 wt pct showed a high tensile strength of more than δb=1000 MPa and good ductility of higher than δ5=10% at ambient temperature.

关键词： Ultrahigh-carbon steel Al Spheroidization

ON THE NONEXISTENCE OF PERIODIC SOLUTIONS FOR LIENARD-TYPE EQUATIONS

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Systems Science and Mathematical Sciences 1999年第2期12卷 184-192页

作者： ZHOU Jin(Department of Applied Mathematics, Hebei University of Technology, tianjin 300130, China) Department of Applied Mathematics HebeiUniversity of Technology Tianjin 300130 China

In this paper, we investigate the nonexistence of periodic solutions for Lienardtype equationSome brief and practical sufficient conditions on the nonexistence of periodic solutions aregiven. Our results can be easily applied to the well-known Lienard equation x+f(x) x +g(x) =0, and substantially extend and improve some known results.

关键词： Lienard-type equations Lienard system periodic solutions nonexistence.