ZHANG Yun
,
LIU Yulin
,
ZHAO Hong' en
,
HU Zhuangqi
,
Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
ChinaZHU Zhiyong
,
WANG Zhengfu
,
Institute of Corrosion and Protection of Metals
,
Academia Sinica
,
Shenyang
,
China ZHANG Yun
,
Associate Professor
,
Institute of Metal Research
,
Academia Sinica
,
Shenyang 110015
,
China
金属学报(英文版)
The A1-2.79Li-1.3Cu-0.7Mg-0.12Zr(8090) alloy has excellent resistance to intergranular and exfoliation corrosion as naturally aged, worst as peak aged and rather better as underaged than as overaged. The corrosion behaviour of the alloy is closely dependent on its microstructure. Under the peak aging condition, the coarse T_2 phase, which is continuously distributed along grain boundaries, has so low corrosion potential in comparison with the ma- trix, this makes the corrosion resistance of the alloy to be deteriorated by anodic dissolution along grain boundaries.
关键词:
AI-Li alloy
,
null
,
null
,
null
JIAO Yuning
,
LIU Qingmin
,
YANG Yuangsheng
,
HU Zhuangqi
,
Institute of Meta] Research
,
Chinese Academy of Sciences
,
Shenyang
,
ChinaGAO Yunyan
,
JIA Guanglin
,
ZHANG Guozhi
,
QIAO YuanjunNortheast University
,
Shenyang
,
China Manuscript received 12 May
,
1994
金属学报(英文版)
Navier-Stokes equation and Lorentz force equation are used to calculate the fluid field of liquid metal of electromagnetic centrifugal casting (EMCC) in this paper. A field equation is given, which shows the azimuthal velocity closely relates to electrical conductivity, magnetic density, viscosity of liquid metal and radius of casting. The results show that the stationary magnetic field can effectively restrain the fluid flow and the relative velocity between liquid metal and casting mould and the velocity gradient at solid / liquid interface increases with rising magnetic density, which has a great effect on the solidification of liquid metal and crystal growth characteristics.
关键词:
fluid field of liquid metal
,
null
Shihong LI
,
Shaoyun FU
,
and Benlian ZHOU (Int. Centre for Mater. Phys.
,
Institute of Metal Research
,
Chinese Academy of Science
,
Shenyang
,
110015
,
China)Qiyun ZENG
,
and Xianrong BAO (Institute of Applied Ecology
,
Chinese Academy of Sciences
,
Shenyang
,
11
材料科学技术（英）
A new technique has been developed for flattening circular natural bamboo culm to plate form for remarkably enhancing its mechanical properties, The enhanced bamboo, cheaper than Al, is then used to reinforce an aluminum alloy for civilian applications. The properties of the composite are greatly enhanced compared to those of the Al alloy. The Al protects bamboo from bioerosion and improves hygroscopicity
关键词:
Shihong LI
,
Ronghui ZHANG
,
Shaoyun FU
,
Xin CHEN and Benlian ZHOU(Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
110015
,
China)Qiyun ZENG(Institute of Applied Ecology
,
Academia Sinica
,
Shenyang
,
110015
,
China)
材料科学技术（英）
In thjs paper. bamboo fiber has been. on micro scale. investigated as a helical. multi-layered hollow cylinder, the stiffness featu res of bamboo bast fiber were compared with those of a multifilament yarn in traditional fiber-reinforced composite materials, Moreover. a biomimetic model of the reinforce ment of fiber-reinforced composite materials was proposed by imitating the fine structure of bamboo bast fiber. The results show that the comprehensive stiffness properties of the cornplicated fine struc ture of bamboo fiber is superior over those of traditional fiber-reinforced composites.
关键词:
SUN LilingInstitute of Metal Research
,
Chinese Academy of Sciences
,
Shenyang
,
ChinaWU QiShenyang College of Technology
,
Shenyang
,
ChinaZHANG Zhiya
,
HU ZhuangqiInstitute of Metal Research
,
Chinese Academy of Sciences
,
Shenyang
,
China
金属学报(英文版)
The effect of trace element B on microstructure of directionally solidified new type Co-base superalloy is studied systematically in this paper. It is found that the addition of B makes the incipient melting temperature of the alloy decline remarkably. Compared with the alloy having a boron content of 0.05 %, the incipient melting temperature of the alloy with 0.7 % B decreases by 197℃. The primary and secondary dendrite arm spacings increase and the volume fraction of interdendritic carbides with fine microstructure becomes bigger with the enhancement of boron content. When the alloy is with 0.7wt %B, M3B2 precipitates in the interdendrites.
关键词:
horon
,
null
,
null
,
null
LIU Zhiguang+ *
,
GUO Jianting *
,
LI Gusong+
,
HU Zhuangqi++State Key Lab. of RSA
,
Institute of Metal Research
,
Chinese Academy of Sciences
,
Shenyang
,
China * Institute of Metal Research
,
Chinese Academy of Sciences
,
Shenyang
,
China
金属学报(英文版)
Mechanical alloying (MA) of Ni50Al45Ti5 (atomic per cent) is studied by in situ thermal analyses, XRD and metallography. The results showed that the alloying process of Ni50Al45Ti5 is similar to that of Ni50Al50. The addition of 5 at.%Ti prolongs the milling time of alloy prior to the explosive reaction in the alloy. The final product is nanocrystalline β-phase NiAl(Ti) (B2 structure). The addition of 5 at.% Ti shows little effect on the lattice parameter of β-phase.
关键词:
mechanical alloying
,
null
,
null
,
null
TANG Hong
,
XIANYU Ze
,
HU Qianli
,
QIAO Guiwen
,
WANG Yongzhong
,
ZHUANG Yuzhi1 1) Institute of Metal Research
,
Chinese Academy of Sciences
,
Shenyang
,
China 2) Northeastern University
,
Shenyang
,
China Manuscript Received 7 March 1995
金属学报(英文版)
In this study, high-Tc YBaCuO superconductors with high Jc value were prepared using MTG(melting-textured growth) method. These superconductors with high density have Jc value in excess of 1.6×104 A/cm2 (77K, zero field) determined by using a d.c. standard four terminal method with the criterion of lμV/cm. The XRD and fractograph analysis revealed that the texture existed in whole MTG-processed YBaCuO sample which consists of the layered and plate-like grains of matrix phase YBa2Cu3Oy unidirectionally aligned along its (103) planes. The experimental results indicated that the connectivity between superconducting grains has been improved greatly and the weak-link problem has been overcome essentially.
关键词:
: YBaCuO high-Tc superconductor
,
null
,
null
,
null
Jinghai YANG
,
Juyuan ZHANG
,
Yizhi GENG (Institute of Solid State Physics
,
Siping Normal College
,
Siping
,
136000
,
China)Bin YAO (State Key Lab. for RSA
,
Institute of Metal Research
,
Chinese Academy of Sciences
,
Shenyang
,
110015
,
China)
材料科学技术（英）
In this paper, for the first time, Ca1-xLnxSiO3 (Ln=Y. La, x=0.1, 0.2) was synthesized with three methods of high temperature (HT) under atmospheric pressure (AP), high temperature (HT) combined with high pressure (HP) and sol-gel method. The sample obtained at the stable range of 4.3-5.0 GPa pressure and 1050-1100℃ temperature with HT and HP method has a cubic perovskite structure, which has the minimum lattice parameter of 0.3535 nm so far,the sample with triclinic structure was obtained by sintering at atmosphere, and the sample synthesized with sol-gel method has monoclinic structure. SEM analysis shows that rare earth ions take the lattice site of Ca, but the distribution of rare earth ions in the samples synthesized with HT and HP is not homogeneous.
关键词:
Guoqing GU+
,
International Centre for Materials Physics
,
Academia Sinica
,
110015
,
Shenyang
,
ChinaGe CHEN
,
College of Systems Science and Systems Engineering
,
Shanghai Institute of Mechanical Engineering
,
200093
,
ShanghaiK.W.Yu
,
Department of Physics
,
Chin
材料科学技术（英）
We build the perturbation expansion method for nonlinear composite media and extend the EMA for nonlinear effective conductivity. Using the solutions of boundary-value problems of a cylindrical in- clusion, we derive formulae for nonlinear effective conductivity.
关键词:
effective medium approximation
,
null
Wenge LIU+
,
Min ZHU
,
Dazhi YANG
,
Dept. of Materials Engineering
,
Dalian University of Technology
,
Dalian
,
116024
,
ChinaZhongguang WANG
,
State Key Laboratory for Fatigue and Fracture of Materials
,
Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
11001
材料科学技术（英）
The thermal-mechanical (T-M) cycles at constant strain of a polycrystalline CuZnAl alloy have been studied in the. present work. In-situ optical microscopic observations have been made to reveal the features of the phase transitions during T-M cycling. The variation of stress-temperature (S-T) curves and electrical resistance-temperature (R-T) curves accompanying with T-M cycling have been measured by tensile test and electrical resistance measurements. It has been found that the polycrystalline CuZnAl alloy shows apparent morphology changes and properties variations in the first cycle during T-M cycling which is called the first cycle effect in the present work. The stable transformation procedure in the T-M cycle is: martensiteparent phase +residual acicular martensite. This residual martensite possesses the character of stress-induced martensite.
关键词:
CuZnAl shape memory alloy
,
null
,
null
