W. Gao
,
T. Sakai and H. Miura( Department of Mechanical Engineering and Intelligent Systems
,
The University of Electro - Communica- tions
,
Chofu
,
Tokyo 182 - 8585
,
Japan)
金属学报(英文版)
An analytical model for dynamic recrystallization (DRX) is studied based on the relative grain size model proposed by Sakai and Jonas, and the characteristic flow behaviors under DRX are analyzed and simulated. Introducing the variation of dynamic grain size and the heterogeneous distribution of disolo- cation densities densities under DRX,a simple method for modeling and simulating DRX processes is developed by using Laplace transformation theory. The results derived from the present model agree well with the experimental results in literatures. This simulation can reproduce a number of features in DRX flow behaviors, for example,single and multiple peak flow behaviors followed by a steady state flow, the transition between them, and so on.
关键词:
dynamic recrystallization
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null
,
null
,
null
Wenbo FEI
材料科学技术（英文）
This paper shows that it is easier to form intelligent ceramics than other materials. Self-adaptive factors and relevant function mechanisms, which determine the formation of intelligent ceramics, are studied and data from the design of the PLZT with complex functions are presented.
关键词:
$ D.L*
,
D.N.He
,
X.J.Bao
,
Y. Q.Zhang
,
X. Y.Ruan
,
J.L. Cheng and J. Y. Jiang 1) National Die & Mold CAD Engineering Research Center
,
Shanghai Jiaotong University
,
Shanghai 200030
,
China 2) Shanghai Volkswagen Automotive Company Limited
,
Shanghai 201805
,
China
金属学报(英文版)
With the combination of a new theoretical formula, physical simulation experiments, the technology of artificial neural network and database, an intelligent system for the prediction of sheet metal drawing capability is constructed for the first time. A modified criterion for sheet metal drawing capability is proposed in this paper, namely, the Technological Limiting Drawing Ratio, TLDR = f(R, n, s, t, F, μ,r_d,r_p…). Based on the studies of other scholars, a new formula is derived to predict the TLDR in this paper. Then a series of orthogonal physical simulation experiments are designed to investigate the effect of technological parameters on the TLDR, and the results are analyzed in the paper. Then the predicting system is constructed with the combination of the theoretical formula, orthogonal experiments, the technology of artifocial neural network and database. The predicted results show good agreements with experimental data, so it can be used to avoid the blindness in the selection of sheet metal before stamping. The system operates under the Windows operating system, and it supports the mechanism of Client/Server as well as Intranet, so the system has high engineering value.
关键词:
TLDR
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null
,
null
,
null
,
null
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null
,
null
Chinese Physics
The dynamic equations of the proton transport along the hydrogen bonded molecular systems have been obtained by using completely quantum-mechanical method to be based on new Hamiltonian and model we proposed. Some quantum-mechanical features of the proton-solitons have also been given in such a case. The alternate motion of two defects resulting from proton transfer occurred in the systems can be explained by the results. The results obtained show that the proton-soliton has corpuscle feature and obey classical equations of motion, while the free soliton moves in uniform velocity along the hydrogen bonded chains.
关键词:
2-component solitary waves;thermodynamic properties;protein molecules;solitons;chains;dynamics;motion;conductivity;excitation;impurity
Journal of Magnetism and Magnetic Materials
The dependence of magnetic properties on the microstructure determined by alloy composition and preparation parameters has been studied in the mechanically alloyed Sm26Fe74-Ti-y(y) (y=0-17), Sm26Fe74-nVn (n=0-9) and Sm26Fe65Ti9-zVz (z=0-7) systems. The addition of Ti to Sm-Fe binary alloy is favourable for the formation of the hard magnetic 5:17 phase, and this phase exists in the investigated composition range (y=1-17) for Sm26Fe74-yTiy. The addition of V leads to the appearance of the 1:12 phase. The composition range for V to stabilize the 5:17 phase is very limited: n=1-5 and z=1-3 for Sm26Fe74-nVn and Sm26Fe65Ti9-zVz, respectively.
关键词:
mechanical alloys;rare-earth - transition metal compounds;microstructure;systems;phases
Mehdi Ebrahimian-Hosseinabadi Fakhredin Ashrafizadeh Mohammadreza Etemadifar Subbu S. Venkatraman
材料科学技术（英文）
In this paper, preparation of nano-biphasic calcium phosphate (nBCP), mechanical behavior and load-bearing of poly (lactide-co-glycolide) (PLGA) and PLGA/nBCP are presented. The nBCP with composition of 63/37 (w/w) HA/β-TCP (hydroxyapatite/β-tricalcium phosphate) was produced by heating of bovine bone at 700°C. Composite scaffolds were made by using PLGA matrix and 10-50 wt% nBCP powders as reinforcement material. All scaffolds were prepared by thermally induced solid-liquid phase separation (TIPS) at -60°C under 4 Pa (0.04 mbar) vacuum. The results of elastic modulus testing were adjusted with Ishai-Cohen and Narkis models for rigid polymeric matrix and compared to each other. PLGA/nBCP scaffolds with 30 wt% nBCP showed the highest value of yield strength among the scaffolds. In addition, it was found that by increasing the nBCP in scaffolds to 50 wt%, the modulus of elasticity was highly enhanced. However, the optimum value of yield strength was obtained at 30 wt% nBCP, and the agglomeration of reinforcing particles at higher percentages caused a reduction in yield strength. It is clear that the elastic modulus of matrix has the significant role in elastic modulus of scaffolds, as also the size of the filler particles in the matrix.
关键词:
Scaffold
Acta Metallurgica Et Materialia
In this paper, the Ni and Ti powder mixture with equiatomic ratio was high energy ball milled and then consolidated by explosive compaction. The microstructures of as-compacted and heat treated bulk samples after explosive consolidation are investigated in detail by transmission electron microscopy (TEM) and high resolution electron microscopy (HREM). The experiment results reveal the microstructure variation during mechanical alloying in Ni-Ti binary systems. It is found that a metastable phase denoted as I phase formed during ball milling and the structure of I phase was determined by both electron diffraction and HREM. Finally, the mechanism of amorphization induced by ball milling was discussed.
关键词:
cu;amorphization;phases
Yuanda DONG Dept.of Metallurgy and Materials
,
Shanghai University of Technology
,
Shanghai
,
200072
,
China
材料科学技术（英文）
The mechanism of mechanically-driven amorphization was extensively surveyed in various systems. It was concluded that the amorphization could occur in the systems of Cu-Zr with a negative heat of mixing (-ΔH) and Cu-Ta with a positive heat of mixing (+ΔH) by mechanical alloying of elemental powders.Such amorphization could also be started from an intermetallic compound Cu_xZr_y with no chemical reaction involved.The energy storage by mechanical attrition should be the driving force for the amorphization.The atomic distribution function and nuclear resonance spectroscopic studies show that the mechanical alloying provides a true alloying on an atomic level.The alloys formed are of a characteristic structure common to the rapidly quenched amorphous alloys.
关键词:
mechanically-driven amorphization
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null
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null
,
null
Acta Physico-Chimica Sinica
The formation of polymer film of propargyl alcohol(PA) and its protective ability against corrosion in Fe/H2SO4 and Fe/H2SO4 + H2S systems have been investigated using impedance measurement. The composition and morphology of the corrosion surface of iron, on which PA polymerized at different times, were obtained with the aid of SEM and AFM as well as EDX. The results showed that PA polymerized into compact polymer film in Fe/H2SO4 and Fe/H2SO4 + H2S systems, which made iron surface smooth and have a morphologies of regular square structure in microscopic level. In Fe/H2SO4 system, macroscopic continuous polymer film of PA was not formed leading to local corrosion on electrode surface. In Fe/H2SO4 + H2S system, the adsorption of H2S and HS- on electrode surface slowed down the formation of polymer film of PA. However, the iron sulfide, produced after a longer time, increased the continuity of the polymer film of PA and therefore, the polymer film could perform its long-term inhibition action.
关键词:
polymer film of PA;H2S;Fe/H2SO4;inhibition effect;acetylenic alcohols;iron corrosion;adsorption;acid
