A Rajeshkannan
,
K S Pandey
,
S Shanmugam
,
R Narayanasamy
钢铁研究学报(英文版)
Cold upsetting experiments were carried out on sintered Fe08%C10%Si04%Cu steel preforms in order to evaluate their deformation characteristics. Powder preforms of 86% of theoretical density, with two different ratios of height to diameter, were prepared using a suitable die set assembly on a 10 MN capacity hydraulic testing machine. Sintering was carried out in an electric muffle furnace for 15 h at 1 150 ℃. Each sintered compact was subjected to incremental loading of 004 MN under dry friction condition till a crack appeared at the free surfaces. The experimental results were critically analysed, the stress as a function of strain and densification was obtained, then the work hardening behaviour was analyzed. It has been found that in the process of enhancing densification, strength and strain hardening is also induced during upsetting, but the work hardening behaviour is not homogenously enhanced against strain and densification.
关键词:
cold upsetting;stress;height strain;densification;work hardening behaviour
Ting DU Longmei WANG Yeming WU Yuqing ZHANG Aisheng LIU Central Iron and Steel Research Institute
,
Beijing
,
100081
,
China
材料科学技术（英文）
The temperature dependences of the equilibrium constants for the reactions RES_((S))=[RE]+[S]. (RE=Ce,La,Nd,Sm,Y),of the standard Gibbs energies for the RES formed and of the interaction coefficients between RE elements and S for the Fe-base,Ni-base and Cu-base solutions are sum- marized.
关键词:
thermodynamics
,
null
,
null
,
null
,
null
Applied Physics Letters
Transport in S(2) molecules sandwiched between Au electrodes is investigated with a combination of density functional theory and the non-equilibrium Green's function method. We consider four different configurations and find that their conductances are related to the details of the bonding geometry. When S(2) connects to pyramidal-shaped electrodes at the top site, the transmission is governed by a resonance and is strongly affected by the bias. In contrast, the transport of the remaining three configurations is through several closely spaced broad molecular orbitals, and the transmission coefficient is almost flat around the Fermi level. (C) 2012 American Institute of Physics. [doi:10.1063/1.3665614]
关键词:
conductance;molecule
YUE Kexiang DONG Yuanchi East China Institute of Metallurgy
,
Ma'anshan
,
China
金属学报(英文版)
The equilibrium constants between Sr-O,Ba-O and Sr-S,Ba-S in liquid iron at 1570℃ and the interaction coefficients concerning these elements have been determined as follows: K_(Sro)=1.897×10~(-7),e_O~(Sr)=-43.8 K_(BaO)=8.204×10~(-8),e_O~(Ba)=-98.0 K_(SrS)=8.356×10~(-7),e_S~(Sr)=-3.9 K_(BaS)=4.083×10~(-7),e_S~(Ba)=-3.5
关键词:
equilibrium
,
null
,
null
,
null
,
null
Zeitschrift Fur Metallkunde
Young's equation is discussed on a thermodynamic basis. The result shows that the equation is a thermodynamic equilibrium of the wetting system rather than a force balance. The equilibrium satisfies the general equilibrium condition, that is, Gibbs free energy should be minimum when the wetting equilibrium is reached. The validity of Young's equation is only limited to some special cases, namely if the droplet shape is an exact sphere sector. It implies that Young's equation can only be used in the case without the action of gravity. If the curve of the liquid surface changes, the term of cos theta in Young's equation should be replaced by another functional form of the contact angle theta. In the discussion, the author suggests that, in the case of a solid, the surface energy should be considered rather than the surface tension, and the concept of a solid surface tension should be reconsidered based on the difference between a liquid surface and a solid surface.
关键词:
J.X. Zhou
,
R.X. Liu
,
L.L. Chen
,
D.M. Liao
,
H.S. Wei
金属学报(英文版)
Numerical simulation of casting's mold filling process is the main and the most important aspect of the foundry CAE technology. But it is time-consuming; it may take dozens of hours or several days. While with the development of computer hardware, numerical simulation of casting's mold filling process has made rapid progress. The simulation results, therefore, have become more and more practical. This study tries to find some clues of the computational time of mold filling process. Firstly, this paper introduces mathematic model and the basic route of numerical simulation of casting's mold filling process. Then the computational time of mold filling process has been carefully studied, and some new and useful results have been gained from the study of the computational time. Finally, this paper has given some real applications of numerical simulation of casting's mold filling process.
关键词:
numerical simulation
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null
,
null
