材料期刊网

EVAPORATION KINETICS OF SnS FROM SnS-Cu_2S-FeS MELTS

Y. X. Hua and C.P. Liu(Depatment of Metallurgy , Kunming University of Science and Technology , Kunming 650093 , China)

金属学报(英文版)

The evaporation kinetics of SnS from SnSCu2SFeS teruary system was investigated against matte grade, tetnperature and carrier gas flow rate. It was demonstrated that the evapomtion process is controlled by gas-phase mass transport. The increases of the flow rote of carrier gas and the temperature could increase the gas-phase mass transport coefficient and the Partial pressure of SnS over the melts, respectively, and hence would appreciably promote the evaporation process. An increase of matte grade could lower the activitv coefficient of SnS in the melts, which in turn would cause the reduction of the evapomtion rate of SnS

关键词: evaporation kinetics , null , null

Study of properties of mixed ferro-ferrimagnetic ising compounds with (A(x)B(1-x))(y)C

Communications in Theoretical Physics

The magnetic properties of the mixed ferro-ferrimagnetic compounds with (A(x)B(1-x))(y)C-z where A(z) B-z and C are three different magnetic ions and form three different sublattices, are studied by using the standard mean-field theory. The phase diagram which is related to experimental work of molecule-based ferro-ferrimagnet ((NixMn1-xII)-Mn-II)(1.5)[Cr-III(CN)(6)].zH(2)O is obtained. The magnetization curves(z) internal energy(z) and specific heat of the same mixed (A(x)B(1-x))(y)C system are also investigated.

关键词: mixed ferro-ferrimagnet;Ising model;phase diagram;internal energy;specific heat;mean-field analysis;magnetic-properties;prussian blue;alloy

Experimental and modeling investigation on SiC(p) distribution in powder metallurgy processed SiC(p)/2024 Al composites

Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing

SiC(p)/2024Al composites were fabricated through the powder metallurgy (PM) technique. The mixing process was modified by using a high ball to charge ratio (BCR), which resulted in improved homogeneity of the SiC(p) distribution, as well as enhanced tensile strengths of the as-pressed composites. A small particle size ratio of aluminum to SiC(p) (PSR) and extrusion also improved the uniformity of the SiC(p) distribution. The improvements by the three approaches were quantitatively analyzed using a critical volume fraction model. The model demonstrates that a small PSR and a large deformation ratio of aluminum particles were two essential factors of improving the homogeneity of the SiC(p). A homogeneity analysis using the Dirichlet Tessellation method provided an additional explanation for the model. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.

关键词: Analytical modeling;Metal-matrix composites;Powder metallurgy;Reinforcement distribution;aluminum-matrix composites;particle-size ratio;mechanical-properties;microstructure;reinforcement

间隙碳原子对(Er_(1-x)Sm_x)_2Fe_(17)C_y化合物形成、结构与磁性的影响

沈保根 , 孔麟书 , 曹蕾 , 王芳卫 , 詹文山 , 郭慧群 , 赵见高

金属学报

用快淬方法制备了单相(Er_(1-x)Sm_x)_2Fe_(17)C_y(x=0.2,<3.0;x=0.5,y<2.0)化合物,研究了它们的形成、结构、稳定性及内禀磁性结果表明,它们在高温是稳定的,随碳含量的增加,晶体结构由六角的Th_2Ni_(17)型向菱方的Th_2Zn_(17)型转变间隙碳原子的引入导致了单胞体积的膨胀、室温饱和磁化强度和Curie温度的增加当y>1.0时,(Er_(1-x)Sm_x)_2Fe_(17)C_y样品在室温均显示出单轴各向异性

关键词: (Er(1-x)Sm_x)_2Fe_(17)C_y间隙碳化物 , interstitial carbides , magnetic properties

Constitutive flow behavior and hot workability of powder metallurgy processed 20 vol.%SiC(P)/2024Al composite

Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing

Constitutive flow behavior and hot workability of the powder metallurgy processed 20 vol.%SiC(P)/2024Al composite were investigated using hot compression tests. The modified Arrhenius-type constitutive equations were presented with the values of material constants in consideration as a function of strain. Dynamic material model (DMM) and modified DMM were used to construct the power dissipation efficiency maps, and Ziegler's instability criterion and Gegel's stability criterion were used to build instability maps. The presence of finer SiC(P) and more boundaries resulting from smaller 2024Al powders shifted the dynamic recrystallization domain of the 2024Al matrix to higher strain rate and lower temperature ranges and decreased the peak value of power dissipation efficiency. Large instable regions were found in the form of flow localization and cavitations located at the matrix/SiC(P) interfaces and within the SiC(P) clusters. By comparison, the Gegel's stability criterion was more sensitive to the instability zones than the Ziegler's instability criterion for this material. (c) 2010 Elsevier B.V. All rights reserved.

关键词: Metal matrix composites;Constitutive equations;Processing maps;Aluminum alloys;Powder metallurgy;6061+20-percent al2o3 composite;matrix composites;working;characteristics;deformation-behavior;al composite;maps;aluminum;20-percent;particles;extrusion

Microstructure and Tensile Properties of ZK60 Alloy Fabricated by Simplified Rapid Solidification Powder Metallurgy (S-RS P/M) Process

Zhenya Zhang

材料科学技术（英文）

This study investigated the microstructures and mechanical properties of ZK60 alloy prepared by a simplified rapid solidification powder metallurgy (RS P/M) processing system (S-RS P/M), which consists of warm press in dry air and hot extrusion. Microstructure characterizations showed that S-RS P/M alloy consisted of magnesium matrix and oxide stringers of ~1 μm in width. TEM (transmission electron microscopy) observations illustrated nano-size magnesia particles (10{30 nm) constituted oxide stringer in detail. Due to a relatively higher volume of nano-size magnesia particle produced during S-RS P/M process, 0.2% yield strength of S-RS P/M ZK60 alloy was found to be as high as 382 MPa, which is 10% higher than that of RS P/M alloy. The improvement in mechanical properties is mainly attributed to the combination effects of Orowan mechanism and coe±cient of thermal expansion (CTE) mismatch because of the approximately same average grain size.

关键词: Microstructure

(Ti_yNb_(1-y))C_x固溶体的机械合金化合成

章桥新

材料研究学报

研究了不同组成的TiC—Nb粉用机械合金化合成的固溶体(TiyNb(1-y))Cx,并与电弧熔炼的(TiyNb(1-y))Cx固溶体比较,结果表明,二者的XRD谱及晶格常数变化完全一致

关键词: 机械合金化 , null , null

Workability Studies in Forming of Sintered Fe-035C Powder Metallurgy Preform During Cold Upsetting

S Narayan , A Rajeshkannan

钢铁研究学报(英文版)

An experimental investigation on the workability behaviour of sintered Fe-035C steel preforms under cold upsetting, have been studied in order to understand the influence of aspect ratio and lubrication condition on the workability process. The above mentioned powder metallurgy sintered preform with constant initial theoretical density of 84% of different aspect ratios, namely, 04 and 06 respectively were prepared using a suitable die-set assembly on a 1 MN capacity hydraulic press and sintered for 90 min at 1200 ℃. Each sintered preform was cold upset under nil/no and graphite frictional constraint, respectively. Under the condition of triaxial stress densification state, axial stress, hoop stress, hydrostatic stress, effective stress and formability stress index against axial strain relationship was established and presented in this work. Further more, attained density was considered to establish formability stress index and various stress ratio parameters behaviour.

关键词: powder metallurgy , failure analysis , plastic behaviour , workability

Multiferroic phase diagram of Y partially substituted Dy(1-x)Y(x)MnO(3)

Applied Physics Letters

The effect of nonmagnetic Y partial substitution at the Dy site in Dy(1-x)Y(x)MnO(3) up to x=0.2 on magnetism, specific heat, and ferroelectricity is investigated, which resulted in a preliminary multiferroic phase diagram. It is revealed that the Y partial substitution suppresses the Dy-spin ordering point (T(Dy)) and ferroelectric ordering point (T(FE)) but enhances the Mn-spin ordering point (T(N)). The interaction between the spins of Dy and Mn is remarkably affected by Y substitution. The measured electrical polarization depends on the Y substitution in a complex way because the ferroelectricity is sensitive to the interaction between the spins of Dy and Mn. (c) 2011 American Institute of Physics. [doi: 10.1063/1.3536506]

关键词: ferroelectricity;polarization

Fe78-2xCrxMoxSn2P10Si4B4C2(x＝2,4)块体非晶合金的制备和性能

张亮 , 卢志超 , 李德仁 , 陆曹卫 , 张宏浩

金属功能材料 doi:10.3969/j.issn.1005-8192.2004.01.001

本文用铜模上吸铸法制备Fe78-2xCrxMoxSn2P10Si4B4C2(x＝2、4,原子百分比)块体非晶合金系列,制备出直径达2.5mm的Fe74Cr2Mo2Sn2P10Si4B4C2非晶合金棒材和直径达2mm的Fe70Cr4Mo4Sn2P10Si4B4C2非晶合金棒材.发现Fe74Cr2Mo2Sn2P10Si4B4C2具有32K的超冷液相区和高达0.61的约化玻璃转变温度,具有很强的玻璃形成能力.当x＝2和x＝4时非晶合金的居里温度分别为538K和455K,饱和磁感应强度分别为1.06T和0.71T.

关键词: 块体非晶合金 , 铜模上吸铸法 , 超冷液相区 , 约化玻璃转变温度