材料期刊网

MICROSTRUCTURE AND MECHANICAL PROPERTIES OF RAPIDLY SOLIDIFIED Al-Fe BASED ALLOYS

W.J. Park , S. Ahn , R. Schmees , and Nack J. Kim(1)(Center for Advaned Aerospace Materials , POSTECH. Pohang 790-784 , Korea )2)(Research Institute of industrial Science & Technology , Pohang 790-600 , Korea )3)(Pratt and Whitney , West Palm Beach , FL , USA Manuscript received 26 August 1996)

金属学报(英文版)

The effects of additions of Ti and W on microstructure and mechanical properties of rapidly solidified Al-Fe-V-Si alloys were investigated. Alloy powders were produced by the centrifugal rotary atomization process. After atomization, powders were screened to various mesh sizes to see the effect of powder size on the mechanical properties.These Powders were consolidated into billets using conventional powder metallurgy process, and then extruded into bar form.Microstructural analysis shows that the W addition results in the heterogeneous microstructure.On the other hand, the Ti addition refines the microstructure.Alloy containing both Ti and W has the highest thermal stability of the dispersoid. These variations in the microstructure are well reflected in the mechanical properties in that the Ti containtng alloys (with or without W) have the higher strength and ductility than the W containing alloy. It also shows that the alloys made of the coarser powders have better combinations of strength and ductility than those made of the finer powders.

关键词: :rapid solidification , null , null

R & D ACTIVITIES ON AEROSPACE MATERIALS IN KOREA

H.M. Kim(Korea Institute of Machinery and Materials , Korea Manuscript received 26 August 1996)

金属学报(英文版)

This paper briefly reviews research and development programs in Korean aerospace industry,with an emphasis on aircraft materials technology. International collaborations in these areas are outlined and the R & D activities are highlighted against the　background of the national economy.It is shown that the investment from government agencies and large enterprises has led to healthy development of aerospace materials industries in Korea.

关键词: :R & D , null , null , null

The tendency of the market and technology of the magnetic materials in Korea

C.O.Kim , Y.Li

材料科学技术（英文）

关键词:

The Tendency of the Market and Technology of the Magnetic Materials in Korea

材料科学技术（英文）

关键词:

Quantitative Analysis for Monitoring Formulation of Lubricating Oil Using Terahertz Time-Domain Transmission Spectroscopy

Chinese Physics Letters

The quantitative analysis of zinc isopropyl-isooctyl-dithiophosphate (T204) mixed with lube base oil from Korea with viscosity index 70 (T204-Korea70) is presented by using terahertz time-domain spectroscopy (THz-TDS). Compared with the middle-infrared spectra of zinc n-butyl-isooctyl-dithiophosphate (T202) and T204, THz spectra of T202 and T204 show the weak broad absorption bands. Then, the absorption coefficients of the T204-Korea70 system follow Beer's law at the concentration from 0.124 to 4.024%. The experimental absorption spectra of T204-Korea70 agree with the calculated ones based on the standard absorption coefficients of T204 and Korea70. The quantitative analysis enables a strategy to monitor the formulation of lubricating oil in real time.

关键词: infrared-spectroscopy;dielectric-properties;zddp;water

Dy3+在Ba3La(BO3)3 中的光致发光

彭夷安 , 曹小妹 , 雷春华 , 刘利民 , 李其华 , 廉世勋

中国稀土学报

研究了Ba3La(BO3)3 基质中Dy3+ 的光致发光特性; 探讨了RE3+的电荷半径比(z/r)和Ce3+, Dy3+ 含量对Dy3+ 发光强度及发光颜色的影响; 分析了Ba3La(BO3)3 中Ce3+ 对Dy3+ 发光的敏化作用; 确定了Dy3+ 的 4F9/2→6H15/2及4F9/2→6H13/2跃迁发射的浓度猝灭机制均为电偶极-电四极相互作用.

关键词: 发光学 , Dy3+ , Ba3La(BO3)3 , 光致发光 , 浓度猝灭 , 稀土

Optical spectra of Ln(3+)(Nd3+, Sm3+, Dy3+, Ho3+, Er3+)-doped Y3GaO6

Journal of Luminescence

Ln(3+) (Ln = Nd, Sm, Eu, Gd, Dy, Ho, Er)-doped Y3GaO6 compounds were prepared by solid-state reaction, and their optical spectra such as absorption, photoluminescence, excitation and time-resolved spectra have been measured for Ln Nd, Sm, Dy, Ho, Er. X-ray powder diffraction shows that the lattice parameters of the compounds (Y(0.96)Ln(0.04))(3)GaO6 decrease with the decrease of the radii of trivalent Ln(3+) ions, indicating that Ln(3+) ions have substituted for y(3+) ions in the lattice. Optical spectra show that there are obvious absorptions at ultraviolet to visible region. The strong emissions in visible and infra-red region show that Y3GaO6 is a suitable host for rare-earth-doped laser crystal and phosphor materials. (C) 2004 Elsevier B.V. All rights reserved.

关键词: crystal-field;absorption-spectra;luminescence;y3ga5o12;glasses;garnet;y2o3;ions;laf3;tb3

Subsolidus phase relations in the ZnO-MoO3-B2O3, ZnO-MoO3-WO3 and ZnO-WO3-B2O3 ternary systems

Journal of Alloys and Compounds

The subsolidus phase relations in the ZnO-MoO3-B2O3, ZnO-MoO3-WO3 and ZnO-WO3-B2O3 ternary systems have been investigated by the means of X-ray powder diffraction (XRD). There is no ternary compound in all the systems. There are five binary compounds and five tie lines in the ZnO-MoO3-B2O3 system. This system can be divided into six 3-phase regions. There are three binary compounds and three tie lines in the ZnO-MoO3-WO3 system. This system can be divided into four 3-phase regions. There are four binary compounds and four tie lines in the ZnO-WO3-B2O3 system. This system can be divided into five 3-phase regions. The possible component regions for ZnO single crystal flux growth were discussed. The phase diagram of Zn3B2O6-ZnWO4 pseudo-binary system has been constructed, and the result reveals this system is eutectic system. The eutectic temperature is 1007 degrees C and eutectic point component is 70 mol% Zn3B2O6. (c) 2007 Elsevier B.V. All rights reserved.

关键词: ZnO-MoO3-B2O3;ZnO-MoO3-WO3;ZnO-WO3-B2O3;Zn3B2O6-ZnWO4;phase relation;zno single-crystals;zinc oxide;growth;moo3-wo3

Gibbs Free Energy of Formation of 3Y_2O_3·5Al_2O_3

XU Xiuguang WANG Changzhen TU Ganfeng Northeast University of Technology , Shenyang , China.

材料科学技术（英文）

Thermodynamic properties of 3Y_2O_3·5Al_2O_3 double compound have been determined with CaF_2 single crystal electrolyte galvanic cell at 1049 K to 1230 K.The galvanic cell used can be expressed as: Pt,O_2(g)丨Y_2O_3(s),YOF_((s))丨CaF_2丨YOF_((s)), 3Y_2O_3·5Al_2O_(3(s))丨Al_2O_(3(s))丨O_2(g),Pt, of which the cell reaction is; 3Y_2O_(3(s))+SAl_2O_(3(s))=3Y_2O_3·SAl_2O_(3(s)) The following result is obtained: A_fG°(3Y_2O_3·5Al_2O_3)=-939500+765.90T±710J/mol where,△fG°(3Y_2O_3·5Al_2O_3)is the free energy of formation of 3Y_2O_3·5Al_2O_3 from Y_2O_3 and Al_2O_3.

关键词: rare earth , null , null

Synthesis, microstructure, and mechanical properties of Al(3)BC(3)

Journal of the American Ceramic Society

In situ synthesis of bulk Al(3)BC(3) was achieved via a reactive hot-pressing method using Al, B(4)C, and graphite powders at 1800 degrees C for 2 h. The reaction path for synthesizing Al(3)BC(3) was investigated. It was found that Al(3)BC(3) formed via the reaction of C, B(4)C, and Al(4)C(3) above 1180 degrees C. Dense Al(3)BC(3) was prepared with a little B(4)C and graphite remained. Microstructure observations revealed the plate-like morphology of Al(3)BC(3) grains. Moreover, the mechanical properties of Al(3)BC(3) were characterized (Vickers hardness of 11.1 GPa, bending strength of 185 MPa, fracture toughness of 2.3 MPa.m(1/2), and Young's modulus of 163 GPa). Young's modulus decreased slowly with increasing temperature, and at 1600 degrees C remained 79% of that at ambient temperature. These results show that Al(3)BC(3) is a promising lightweight high temperature structural material.

关键词: boron-carbide;high-temperature;youngs modulus;aluminum;al8b4c7;friction;ti3alc2;ti3sic2;composites;ceramics