材料期刊网

TEM STUDY OF C-B_4C-SiC COMPOSITES WITH SILICON ADDITIVE

ZHAO Lihua , WU Lijun , HUANG Qizhong , YANG Qiaoqin 1)(Material Research and Test Center , Hunan University , Changsha , China)2)(Powder Metallurgy Research Institute , Center-South University of Technology , Changsha , China)3)(Laboratory of Atomic Imaging of Solids , Institute of Metal Research , Chinese Academy of Science , Shenyang , China)Manuscript received 18 April 1995

金属学报(英文版)

C-B4C-SiC composites with silicon additive obtained by the hot press sintering method are studied by means of transmission electron microscopy(TEM).When the specimens are heated to 1800℃,their structure does not change.When the specimens are heated to 2000℃,carbon begins to graphitize. Moreover,two monoclinic phases are observed.One monoclinic phase named as the M phase belongs to C-center monoclinic lattice with a=0.90nm,b=0.59nm,c=0.54nm and β=119.3°.The other monoclinic phase named as the Ml phase also belongs to C-center monoclinic lattice but with a=0.85nm,b=0.49nm,c=0.53nm and β=123.6°.

关键词: :C-B_4C-SiC composite , null

Enhanced Bamboo Reinforced Aluminum Laminates

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（英文）

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

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THE DESIGN OF AN INTEGRATED SYSTEM FOR PREDICTING AND ANALYZING SOLDER JOINT SHAPE AND RELIABILITY IN SMT

C. Q. Wang , X. J. Zha , C. Q. Zhang , S. Q. Yang , C. Z. Wang( 1)National Lab of Advanced Welding Technology , HIT , Harbin 150001 , China 2)Shanghai Institute of Metallurgy , Chinese Academy of Science , Shanghai 200050 , China)

金属学报(英文版)

Solder joint reliability is one of critical problems detemining whether Sirface Mount Technology (SMT) can be used in the prohotion of important electronic products. Optimizing solder joint shape is one of effective ways to improve SMT solder joint reliability.In this paper. based on the theorem of minimum potential energy, an energy model of 3 - D solder joint shape is established,and the forma- tion of solder joint is numerically simulated by Surface Ecolver program. On the basis of the prediction of SMT solder joint shape,the mechanical model of analyzing solder joint reliability is established. An elasto - plasto - creep mateial model and its mechanical constitutive equaton are established for SnPb solder alloy, and the stress/strain response of SMT solder joint under thermal cyclical loabing is ana- lyzed with nonlinear 3 - D FEM. The fatigue life of solder joint is predicted according to Coffin- Manson fatigue life model. An integrated system for Predicting and analyzing SMT solder joint shape and reliability(PSAR) is developed.The system can analyze efficiently SMT solder joint reliability with the variation of structural parameters in the joint and give the optimal structure.

关键词: SMT , null , null , null

EFFECT OF REVERT RECYCLE TIMES ON MICROSTRUCTURE AND FATIGUE PROPERTIES IN COBALT BASE SUPERALLOY K640S

T.L. Wang 1 , 2) , J.T. Guo 1) , D.S. Xia 2) , Y.Wang 1) and H.C. Yang 2) 1) Institute of Metal Research , Chinese Academy of Science , Shenyang 110015 , China 2) Material and Metallurgical Institute Northeastern University , Shenyang 110006 , China

金属学报(英文版)

Effect of revert cycles on microstructure and fatigue properties of cast cobalt base superalloy K640S has been investigated. The results show that: at 70 times of cool heat cycles, there were microcracks found in seven times revert and ten times revert. With the increasing of thermal fatigue cycles, the crack of revert grows a little faster than virgin. When the cycle time reaches 200, the crack length for both virgin and reverts have been as long as 2mm. The low cycle fatigue life has no remarkable change, with the increase of revert cycles at 815℃, 360MPa ,0 5Hz. With the times of cycles increasing, it is found that the content of impurity and gas in alloy change a little, and there is no obvious change for dendrite microstructure.

关键词: revert , null , null , null , null

INFLUENCE OF EXTRUSION ON DAMPING CAMCITIES OF AS-SPRAY DEPOSITED HIGH SILICON ALLOY ZA27 MODIFIED BY CERIUM

YC. Liu , G.C. Yang , YL. Lu and Z.G. Zhu (State Key Lab. of Solidification Processing , Northwestern Polytechnic University , Xi'an 710072 , China Laboratory of Internal Friction and Defects in Solids , Chinese Academy of Science , Hefei 230031 , China )

金属学报(英文版)

The effects of cerium modification and extrusion on the resultant damping behavior and mechanical properties of the as-sprayed high silicon alloy ZA27 were investigated in an thort to develop a new functional material possessing high damping capacity and good mechanical properties. The damping capacity, as well as the rslative dynamic modulus, was tneasured at frequencies of 1 and 4 Hertz over the 30 to 200℃runge. At below 80℃ the as-sprayed materials appear to be approximately Asquency independent. Above 80℃, the,naterials becotne temperature sensitive, exhibiting the highest damping for the lowest hequency. The extruded, as-sprayed high silicon alloy ZA27 modified by cerium has the highest damping capacity and elongation values among them. The micro8tructure of the as-sprayed high silicon alloy ZA27 modified by 0. 5 wt% cerium was made up of fine lamellar eutectoid, porositg, a light dot-like phase and a polygonal silicon-rich phase. Finally, the opemtive damping tnechanisms were discussed in light of the data obtained hem characterization of microstructure and damping capacity. The high damping capacity was attributed primarily to phase interface thermoelastic damping between the lamellar phases with various substrvctures,except for the grain refinement.

关键词: spray deposition , null , null , null

An Anomalous Kerr Loop of LaBaMnO Thin Film

Bihui HOU , Qinlun XU , Shizhuo JI , Tianpei ZHANG and Peng PENG (Dept. of Physics , University of Science & Technology of China , Hefei 230026 , China) Changhe SHANG and Yinjun WANG (State Key Lab. of Magnetism , Institute of Physics , Chinese Academy of Science

材料科学技术（英文）

An anomalous Kerr loop was observed in an oriented LaBaMno film annealed in oxygen. Many tiny crystal columns were observed with scanning tunneling microscope and magnetic force microscope. The magnetic moment m in the column is perpendicular outward to the surface, which forms a surface phase with spin pinning state. This spin pinning results in the obvious asymmetrical Kerr loop of magneto-optical effect when the magnetic field is in the two opposite directions vertical to the surface.

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Sputtering Rates of Alloys in Glow Discharge

Jianshi REN and Gongshu ZHANG (Institute of Metal Research , Chinese Academy of Science , Shenyang , 110015 , China)Zhenshu WANG and Jinwei ZHAO (Shanghai University of Technology Shanghai , 200072 , China)

材料科学技术（英文）

The sputtering rates of alloys were investigated under constant Ar pressure and voltage supplied.The alloys studied in this work range from binary intermetallic alloys to ternary and quaternary alloys. It is revealed that the sputtering rates of alloy targets under steady states are where q is the sputtering rates of alloys, Ci the weight percentage of i-th component in the alloy,and qi0 the sputtering rate of pure metal of i-th component.

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Guangzhou Institute of Energy Conversion,The Chinese Academy of Sciences,Guangzhou 510070,China

B.W. Wang , H. Shen

金属学报(英文版)

Ni-Cr System solar selective thin solid films were prepared by d.c. magnetron reactivesputtering under the atmosphere of O2 and N2. Ni-Cr alloy was chosen as targetmaterial and copper sheets as substrate. Using SEM, Spectrophotometer and Talystepto analyze the relations between the selective characteristic and the structure, theformation and the thickness of the thin films. The aim is to obtain good solar selectivethin films with high absorptance and low emittance, which is applied to flat plate solarheat collectors.

关键词: solar selective thin film , null , null , null

CHINESE JOURNAL OF METAL SCIENCE & TECHNOLOGY

材料科学技术（英文）

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The Abstracts of Papers in Special Issue on the Seventh Five Year Project for Rare Earths of Chinese Academy of Sciences(in Chinese)

熊炳昆

中国稀土学报

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