材料期刊网

HIGH STRAIN RATE SUPERPLASTICITY OF DISCONTINUOUS CERAMIC FIBER REINFORCED ALUMINUM COMPOSITES

T. Imai , L. Geng , J. F. Mao and I. Tochigi 1) National Industrial Research Institute of Nagoya , 1-1 Hirate-cho , Kita-ku , Nagoya , 462-8510 , Japan 2) School of Materials Science & Engineering , Harbin Institute of Technology , Harbin 15001 , China 3) Kanagawa High-Technology Foundation , Kanagawa Science Park , 3-2-1 , Sakado , Takatsu-ku , Kawasaki , Kanagawa 213 , Japan

金属学报(英文版)

β-Si3N4 whisker reinforced aluminum composites was fabricated by squeeze casting before extrusion and an effect of content of Mg on the High Strain Rate Superplastic- ity (HSRS) were investigated, The optimum temperature of the composites at which maximum total elongation is obtained decreases according to magnesium content and the β-Si_3N_4w/Al-3Mg exhibits the total elongation of about 200% at the strain rate of 10~(-1) s~(-1) and at 853-858 K, although the β-Si_3N_4w/Al-0Mg composite shows about 100% elongation at the strain rate of about 1×10~(-1) s~(-1) at 903-913 K. Optimum strain rate of the composites fabricated by squeeze casting was about 1×10~(-1) s~(-1) but TEM observation indicates that the β-Si_3N_4w/Al-Mg has a fine grain of about 2- 3μm and that the whisker might no react with Mg at the interfaces, although the β-Si_3N_4 whisker react with aluminum matrix.

关键词: high strain rate superplasticity , null , null

CONGRATULATIONS TO PROF. T. KO'S 90th BIRTHDAY Editorial Board of ACTA METALLURGICA SINICA

金属学报(英文版)

关键词:

100t复吹转炉高冷料比优化冶炼工艺实践

黄标彩

钢铁研究

介绍三钢对100t复吹转炉的底吹工艺和脱磷工艺进行优化的实践.结果表明,在高冷料比条件下,转炉一倒钢水平均w(P)从0.047%下降到0.027%;平均w(Mn)从0.22%提高到0.25%;平均终渣w(TFe)下降3.26%;平均终点w(O)降低370×10-6;平均终点w(C)×w(O)积下降0.0007%.钢铁料消耗从1088kg/t下降到1082kg/t;合金加入量从10.2kg/t下降到9.4kg/t.

关键词: 复吹转炉 , 脱磷 , 冶炼工艺

100 t交流竖式电弧炉冶炼电耗技术分析

王新江 , 傅杰 , 李晶 , 宋万平 , 靳秀礼

钢铁

对影响电弧炉冶炼电耗的主要因素进行了理论分析,降低电弧炉冶炼电耗的基本途径是缩短冶炼周期.开发了改性生铁在电弧炉中的应用技术;优化了供电曲线,使有功功率超过变压器额定功率的80%;在100t交流竖式电弧炉应用冶炼周期综合控制理论,使得电弧炉冶炼周期平均为41 min,生产率超过每吨炉容量每年1万t,冶炼电耗平均为222 kW·h/t.

关键词: 交流竖式电弧炉 , 电耗 , 冶炼周期

SIMULATON ON WELDING PROCESS OF T - JOINTS

H. Y. Zhao , A. L. Lu , Q. Y. Shi and F. Yan (Welding Division , Department of Mechanical Engineering , Tsinghua University , Beijing 100084 , China)

金属学报(英文版)

T-joints are widely used in ship manufacturing and other welding structures.The welding residual stress and deformation hare significant influence on failure and service life in welding structures.By us- ing of 3D thermal elasto - plastic FEM, the temperature fields,stress fields and deformation of weld- ing processes on T - joints are analyzed in this paper.The moving heat source is considered in the com- putation. Moreover, weld metal filling and multiple - pass welding are simulated using activate/deac- tivate ability.For avoiding "locking" in full integration elements of welding computation,the re- duced intergration elements are used in weld area.The nonlinear FEM analysis program MARC is used to complete the computations, as well as its user subroutines that are programmed to develop the special techniques needed in the simulation of welding process.Some different welding procedures are com- pared, and the welding residual stress and deformation are discussed in details.

关键词: welding , null , null , null , null

Magnetic properties of 1T-TaS2

Chinese Physics Letters

The magnetic properties of 1 T-TaS2 and 1 T-Fe-0.07 Ta-0.93 S-2 have been studied, Experimental results show that the phase transition temperature of 1 T-TaS2 is a function of the magnetic field, At low temperatures, both compounds are in a mixed state of charge density wave -spin density wave due to the coherent superposition of antiferromagnetic coupling.

关键词: density

T300和T700炭纤维的结构与性能

李东风 , 王浩静 , 贺福 , 王心葵

新型炭材料 doi:10.3969/j.issn.1007-8827.2007.01.011

利用SEM、元素分析、XRD和激光Raman光谱研究了T300和T700的形貌、化学组成和微观结构参数.结果发现:T700炭纤维表面光滑,而T300炭纤维的表面有大量的沟槽.表明前者是用干喷湿纺原丝,后者是用湿法纺丝原丝.两种纤维的断面均呈现出颗粒状特征.T700的含碳量高于T300,含氮量低于T300.两者的微观结构参数(d002、La和Lc)差异佐证了T700的炭化温度高于T300.T700的择优取向角Z比T300小2.3°,是石墨微晶致密有序排列的反映,因而使其体密度比T300高2.27%,空隙率低7.54%.所以致密化赋予了T700较高的拉伸强度.

关键词: PAN基炭纤维 , 微观结构 , XRD , Raman光谱

热变形纳米晶Nd-Fe-B磁体2和5T时磁化强度与取向度的拟合关系式

鲁贻虎 , 王姝隽 , 刘新才 , 潘晶

中国稀土学报 doi:10.11785/S1000-4343.20130605

测量和分析了热压热变形各向异性纳米晶Nd-Fe-B磁体磁取向度I、整个磁体的易磁化轴与热变形压力方向的夹角α,磁体密度ρ,主相体积百分数1-β,磁化强度的关系,拟合出2和5T充磁磁场时具有不同磁取向度热变形磁体的磁化强度分别为MS2=(1-β)MSTO ρ/ρO(1-0.35108/I2 +0.18622/I4)和MS5=(1-β)MSTO ρ/ρO(1-0.19326/I2 +0.09545/I4),并与已有相关文献的实验数据的测量值进行了计算比对,发现2和5T充磁场时的计算值与实测值的误差分别在9.05％和0.89％.在1123 ～1163 K范围热变形,钕铁硼磁体的磁取向度、2和5T时磁化强度均是先增加后减小,在1148 K时达到最大值1.894,1.337和1.386 T.消除热变形粗晶粒带和晶粒混乱区,将提高热变形磁体的磁取向度和磁化强度.

关键词: 拟合公式 , 磁化强度 , 取向度 , 纳米晶 , 永磁材料 , 热变形

Effects of Mn and Cu doping in La(T,Al)(13) (T=Fe,Co) on crystal structure and magnetic properties

Journal of Alloys and Compounds

The crystal structures and magnetic properties of Mn and Cu-doped in La(T,Al)(13) (T=Fe,Co) compounds have been investigated by means of X-ray powder diffraction and magnetic measurement. The results show that Mn doping stabilizes the cubic NBZn13 type structure, but both the magnetic moments and the Curie temperature decrease. Cu doping decreases the homogeneity region of the cubic NaZn13 type structure. (C) 1997 Elsevier Science S.A.

关键词: ternary La aluminides;Fe rich rare earth intermetallics;magnetic;properties;intermetallic compounds;rare-earth;transition;nd

S-T-B流型判别方法

孙长征 , 宇波 , 魏进家

工程热物理学报

通过分析气相、液相、管壁之间的关系,将气液混输管道中的流型划分为五种,并总结了各流型的特点及气液相和管壁间的几何关系;在对Baker、Brill、Beggs-Brill、Taitel、段塞特征分析(SCA)等流型判别方法进行分析的基础上,提出了一种综合使用SCA、Taitel和Brill三种方法的流型判别方法 S-T-B法.经算例验证,该方法对气液两相混输的流型判断准确性较高,可以作为气液混输工艺计算过程中确定流型的方法.

关键词: 气液混输 , 流型 , 段塞特征分析法 , S-T-B