J. Zhang (Department of Metallurgy
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University of Science and Technology Beijing
,
Beijing 100083
,
China)
金属学报(英文版)
Based on the facts that cations and anions of molten salts and binary basic oxide solid solutions do not separate from each other as well as that the electric conductivities of mattes are greater than that of salts and basic oxide solid solutions, the calculating models of mass action concentrations for binary and ternary mattes involving eutectic have been formulated. The results of calculation agree well with the values measured;this in turn shows that the calculating models can reftect the structural characteristics of the mattes concerned.
关键词:
matte
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Journal of Materials Research
The morphology of the dark and bright regions observed by transmission electron microscopy for the Zr(64.13)Cu(15.75)Ni(10.12)Al(10) bulk metallic glass strongly depends on the ion beam parameters used for ion milling. This indicates that the ion beam could introduce surface fluctuation to metallic glasses during ion milling.
关键词:
room-temperature
LIU Chunpeng XU Yousheng HUA Yixin Kunming Institute of Technology
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Kunming
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650093
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China.
材料科学技术（英文）
In applying the microwave radiation to extractive me- tallurgy,it is essential first of all to find the extent of microwave energy absorbed by various minerals experi- mentally.In this paper,more than 25 kinds of common useful minerals have been individually irradiated by a 500 W,2450 MHz microwave source in an enclosed quartz crucible to ascertain their heating temperature in a definite time.In addition,the reduction and cbloridization tests were also carried out on the titanomagnetite concentrate and pentlandite with microwave heating,respectively. These experiments indicate potential applications of util- izing microwave energy in extractive metallurgy.
关键词:
microwave radiation
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Z. T. Ma and D. Janke(Institute of Iron and Steel Technology
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Freiberg University of Mining and Technology
,
Germany)
金属学报(英文版)
Useder certain conditions, nonmctallic inclusions such as oxides, sulfides, nitrides and carbides are no longer harmful to sted service properties. With the new concept of oxide metallurgy, these properties can be improved by generating fine oxide inclusions which serve as heterogeneous nuclei for sulfide and fine ferrite[1-4]. A novel continuous casting (CC) process is expected to be created with the utilization of oxide metallurgy. This is also useful for the forthcoming technologies of direct rolling and near-net-shape casting. The main idea of oxide metallurgy consists of an alternative oxidation technology. It is based on steels treated by complex metals such as Ti, Zr, Ti-Zr alloys and rare earth metals. The selected deoxidants should follow the required conditions which are concluded in this paper.
关键词:
oxide
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null
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null
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Journal of Physics-Condensed Matter
The temperature dependences of the magnetization, internal energy and specific heat in a three-sublattice ferrimagnet or ferromagnet with /J(ab)/ = /J(bc)/ not equal /J(ca)/ are calculated within the framework of the linear spin-wave approximation, by employing retarded Green's functions. For both the ferromagnet and the ferrimagnet, the internal energy and the specific heat decrease with increasing J ' /J and/or the value of the spins. For fixed values of S,, Sb, S, and J ' /J, the internal energy and the specific heat increase, whereas the sublattice magnetization decreases with increasing temperature theta. The three-sublattice ferrimagnet has some particular characteristics which are not shown by the systems with two sublattices. For ferrimagnets, the antiferromagnetism of the system becomes weaker with increasing J ' /J. The sublattice magnetization at low temperatures (also the magnetization M(0) at 0 K) of a ferrimagnet increases with increasing J ' /J for fixed values of S(a), S(b) and S(c). The effects of the spins S(a) (S,) and Sb On the magnetizations of other sublattices differ. The characteristics of the a-sublattice are the same as those of the c-sublattice, due to their similarity as well as the symmetry of the system. The behaviours of the b-sublattice are different from those of the a- and c-sublattices, due to the asymmetry of the three-sublattice system. The spin-value dependences of the spin deviation Deltam per spin land also the energy for the zero-point quantum fluctuation) of the system are different for different sublattices. These differences are ascribed to the asymmetry of the three-sublattice systems, which leads to the new intrinsic properties of the systems.
关键词:
layered heisenberg ferrimagnets;spin-wave theory;elementary;excitations;superlattices;systems;magnetoresistance;antiferromagnet;interfaces
Physical Review B
The Hamiltonian for a four-sublattice Heisenberg ferrimagnet or ferromagnet with different exchange constants (J(ab) = J(cd) not equal J(bc) = J(da)) was established. An extended Bogoliubov transformation was developed by solving an equation group, consisting of 20 equations and 20 unknowns. The procedure for solving the equation group was carried out by introducing a simple way of reducing the numbers of the equations and the unknowns. The spin-wave spectra in the present system have been determined by performing the standard Holstein-Primakoff transformation and the Bogoliubov one. It has been found that the spin-wave spectra of the present system depend on the exchange constants and that the degeneracy of the spin-wave spectra remains. The results for a special case (J(ab) = J(bc)) i.e., an antiferromagnet are discussed briefly. The spin-wave spectra of the four-sublattice Heisenberg antiferromagnet are found to be degenerative also and they are linear in k for small k.
关键词:
model
Yong LIU
,
Lifang CHEN
,
Weifeng WEI
,
Huiping TANG
,
Bin LIU
材料科学技术（英文）
Ti-4.5Al-6.0Mo-1.5Fe, Ti-6Al-1Mo-1Fe and Ti-6Al-4V alloys were prepared by blended elemental powder metallurgy (PM) process, and the effects of Nd on the microstructures and mechanical properties were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). It was found out that the addition of Nd increased the density of sintered titanium alloys slightly by a maximum increment of 1% because small amount of liquid phase occurred during sintering. The addition of Nd shows little effect on the improvement of tensile strength, while the elongation is significantly improved. For example, the elongation of Ti-4.5Al-6.0Mo-1.5Fe can be increased from 1% without addition of Nd to 13% at a Nd content of 1.2 wt pct.
关键词:
Powder metallurgy titanium alloy
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