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Refinement Role of Electromagnetic Stirring and Calcium in AZ91 Magnesium Alloy

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Journal of wuhan University of technology({2.s science Edition) 2008年第2期23卷 194-197页

作者： HAN Hui LIU Shengfa KANG Liugen LIU Linyan (school of materials {2. and engineering,wuhan University of technology,wuhan 430070,China) school of materials {2. and engineering Wuhan University of Technology Wuhan China

Effects of calcium addition and electromagnetic stirring on the microstructure of AZ91 magnesium alloy and refinement mechanism were *** results show that calcium addition ranging from 0.1wt% to 0.3 wt% does not lead to formation of any new phases but cause the refinement of as- cast ***,combined calcium alloying and electromagnetic stirring significantly decrease the grain size,change the morphologies of theβ-Mg17Al12.hases,and reduce their volume *** minimum grain size of AZ91 alloy is obtained in the case of the addition of 0.2.wt%Ca with exciting voltage of 100 *** microstructural refinement is attributed to the increase of the degree of undercooling and nucleation temperature of primaryα-Mg phases on the basis of DTA analysis results.

关键词： AZ91 magnesium alloy electromagnetic stirring calcium microstructural refinement

Structure and Magnetic Properties of Ni-doped ZnO Powder

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Journal of wuhan University of technology({2.s science) 2010年第5期25卷 770-773页

作者：高放赵俊 Department of Electronic science and technology Huazhong University of Science and Technology

Ni-doped ZnO nanopowder （Zn0.98Ni0.2.） was synthesized by improved coprecipitation method. The average particle size of the powder was estimated to be 50 nm. The powder was then processed by thermal treatment. Samples were annealed at 1 073, 1 2.3, and 1 473 K, respectively. The solubility of NiO in ZnO and the lattice parameters of ZnO both increased with the temperature. The magnetic property of the doped samples was examined, and hysteresis loops were got. The results showed all the samples were ferromagnetic, while powder processed at 1 2.3 K for 4 h got a highest saturation magnetization （Ms） of 0.0457 emu/g. Also, magnetic properties were related to the grain size of the powder.

关键词： ferromagnetism diluted magnetic semiconductor Ni-doped ZnO coprecipitation solid state reaction

METHOD TO SOLVE ELASTIC CONJUGATE SURFACES IN MULTI-TEETH MESHING

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Chinese Journal of Mechanical engineering 2002年第4期15卷 348-352页

作者： Yi Chuanyunschool of Mechanical science and {2., Huazhong University of science and technology,wuhan 430074, China school of Mechanical science and {2. Huazhong University of Science and Technology Wuhan 430074

A method to solve the elastic conjugate surfaces in multi-teeth meshing ispresented. In mechanical manufacturing and design, there exist a lot of problems relating toconjugate surfaces, such as three-dimensional engagement, steel rolling and workpiece machining,which cause great effects on the quality of machining and performances of transmission. This methoddescribes relation between conjugate motion and elastic deformation in the process of mesh-in andmesh-out, and can be used to determine the profile of gear tooth by a certain given load sharing.

关键词： multi-teeth meshing elastic conjugate surfaces

Modification of Fluorgypsum as Cement Retarder

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Journal of wuhan University of technology({2.s science) 2007年第4期22卷 745-748页

作者：王锦华 school of materials {2. and engineering Wuhan University of Technology

The chemical composition and mineral structure of fluorgypsum as well as its harm to application in cement were elaborately analyzed. The primary fluorgypsum was modified and its applications in cement＇s production were studied. The technological flow chart of preparing modified fluorgypsum was given. Experimental results indicate that hydration ratio the modified fluorgypsum through adding compound additive for 14d is about 70%. The modified fluorgypsum as cement retarder has certain stimulation to fly ash and increases the strength of compound cement. In addition, its adding amount is lower than that of natural gypsum. The modified fluorgypsum is a good substitute for natural gypsum.

关键词： fluorgypsum industry waste modification cement retarder

Piezoresistivity of Carbon Fiber Graphite Cement-based Composites with CCCW

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Journal of wuhan University of technology({2.s science) 2011年第2期26卷 340-344页

作者：范晓明 school of materials {2. and engineering Wuhan University of Technology

The electrical conductivity and piezoresistivity of carbon fiber graphite cement-matrix composites（CFGCC） with carbon fiber content（1% by the weight of cement）,graphite powder contents （0%-50% by the weight of cement） and CCCW（cementitious capillary crystalline waterproofing materials,4% by the weight of cement） were *** experimental results showed that the relationship between the resistivity of CFGCC and the concentration of graphite powders had typical features of percolation *** percolation threshold was about 2.%.A clear piezoresistive effect was observed in CFGCC with 1wt% of carbon fibers,2.wt% or 30wt% of graphite powders under uniaxial compressive tests,indicating that this type of smart composites was a promising candidate for strain *** measured gage factor （defined as the fractional change in resistance per unit strain） of CFGCC with graphite content of 2.wt% and 30wt% were 37 and 2.,*** the addition of CCCW,the mechanical properties of CFGCC were improved,which benefited CFGCC piezoresistivity of stability.

关键词： carbon fiber graphite cement-based composites cementitious capillary crystalline waterproofing materials electrical resistivity piezoresistivity

Development of Mathematical Model on Preparation of Functionally Graded material by Co-sedimentation

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Journal of materials science & {2. 2001年第2期17卷 275-277页

作者： Zhongmin YANG, Lianmeng ZHANG and Qiang SHEN Institute of materials science and {2., wuhan University of technology, wuhan 430070, China Inst. of Mat. Sci. Wuhan Univ. of Technol. Wuhan 430070 China

From the process of sedimentation the mathematical relationships among deposition Volume and powder properties as well as sedimentation parameters were deduced. Based on the formula a mathematical model was set up and simulated through the computer. At last the validity of mathematical model was supported by the representative experiment on Ti-Mo system FGM prepared by co-sedimentation.

关键词： Co Mo Development of Mathematical Model on Preparation of Functionally Graded material by Co-sedimentation

Relationship between Low Temperature Toughness and Microstructure in Low Activation Fe-Cr-Mn(W,V)Steel for Fusion Reactors

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International Journal of Minerals,Metallurgy and materials 1999年第2期13卷 111-115页

作者： Benfu Hu Chengchang jia(material science and engineering school, University of science and {2. Beijing, Beijing 100083, China) material science and engineering school University of Science and Technology Beijing Beijing 100083 China

Fe-Cr-Mn (W, V) austenite steel was researched in order to supply a theory base for the first wall materials of fusion *** included vacuum melting, forging, annealing, solution treatment, Charpy impact tests and microstructure observation. Theresults show that the imped value decreases with the test temperature decreasing. In this system, there is ductile/brittle transition. Themechanism of this decrease of the impact value is considered to be due to γ - ε transformation in sub-stable austenite steel and stoppingoverlapping sacking fault by grain boundaries in stable austenite steel.

关键词： fusion reactor first wall materials low temperature toughness Fe-Cr-Mn system

Phenomenological Modeling of Warm Compaction and Experimental Verification

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International Journal of Minerals,Metallurgy and materials 2000年第4期14卷 292-295页

作者： Shiju Guo, Tao Lin (material science and engineering school, University of science and {2. Beijing, Beijing 100083, China) material science and engineering school University of Science and Technology Beijing Beijing 100083 China

A phenomenological modeling approach to establishing the warm compaction equation and curves by modifying the regression equation of the room-temperature compaction curve is presented. An enhanced factor of compacting pressure is introduced into the equation in order to reveal the effects of powder/die temperature and filling height of powders on green density. Compaction curves yielded from this equation are consistent with the experimental data of ATOMET grade iron powders. The curves show that the powder/ die temperature should reduce as the filling heights of powders increase and that in some cases warm compaction can not give rise to a higher green density.

关键词： powder metallurgy warm compaction compaction equation materials

Annealing Texture Evolution of Ti-IF Steel during Batch Annealing

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International Journal of Minerals,Metallurgy and materials 1998年第3期12卷 175-179页

作者： Jing Shi Xianjin Wang(material science and engineering school, University of science and {2. Beijing, Beijing 100083, China) material science and engineering school University of Science and Technology Beijing Beijing 100083 China

Texture development and recrystallization behavior of Ti-IF steel during Batch Annealing (BA) were investigared with X-ray diffraction and EBSP in lab, and the results were compared with research work on continu ous annealing (CA) with rapid heating rate. The basic tendencies are similar that eary nucleation takes place in ND fibers, RD fibers are consumed at the end of recrystallization, and ND texture dominates over annealing texture. However, the detailed texture transformation during batch annealing is different and somewhat more compicated than tha in rapid-heating process. Moreover, misorientation plays an important role in texture transformation of BA In addition, the results of EBSP are consistent with that of ODF well.

关键词： Ti-IF steel texture batch annealing X-ray diffraction EBSP