Yanjun ZHENG
,
Lishan CU
,
IYan LI
,
Dazhi YANG
材料科学技术（英文）
The reverse martensitic transformation of TiNi shape memory alloy fibers embedded in a pure aluminum matrix was studied in this paper. Results showed that the phase composition of the TiNi alloy fibers prior to prestraining at the room temperature had a significant influence on the differential scanning calorimetry (DSC) results of the composites. By a comparison to the high temperature X-ray diffraction (XRD) results, it was confirmed that the martensite was divided into two groups: the self-accommodating martensite (SAM) and the preferentially oriented martensite (POM). The evolving process of the separation of martensite was discussed.
关键词:
Shape memory alloy
,
null
,
null
,
null
Xiuhua CHEN
材料科学技术（英文）
Some information on how to use in-situ determined diffusion coefficient of Cu to make barrier layer of Cu metallization in ultra large scale integrations (ULSIs) was provided. Diffusion coefficients of Cu in Co at low temperature were determined to analyze Cu migration to Co surface layer. The diffusion depths were analyzed using X-ray photoelectron spectroscopy (XPS) depth profile to investigate the diffusion effect of Cu in Co at different temperatures. The possible pretreatment temperature and time of barrier layer can be predicted according to the diffusion coefficients of Cu in Co.
关键词:
Cu diffusion
,
null
,
null
,
null
Acta Materialia
A comprehensive transmission electron microscopy (TEM) study was conducted to investigate the growth mechanisms Of Cu(3)Sn on polycrystalline and single crystalline Cu substrates in solder joints. On single crystalline Cu the solder reflow process resulted in the growth of columnar Cu(3)Sn grains aligned in a thin uniform layer perpendicular to the interface, while a thick Cu(3)Sn layer formed from fine equiaxed grains on the polycrystalline substrate. In the subsequent solid state aging, columnar growth Of Cu(3)Sn continued on the single crystalline Cu before it was replaced by nucleation and growth of new triangular Cu(3)Sn grains at the triple junction sites of the Cu/Cu(3)Sn interface. On the polycrystalline Cu the solid state aging caused much more rapid growth of the Cu(3)Sn layer due to nucleation and the growth of new Cu(3)Sn grains at both the Cu/Cu(3)Sn and Cu(6)Sn(5)/Cu(3)Sn interfaces. These different growth behaviors Of Cu(3)Sn were related to the diffusive supply of reactive elements. (C) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
关键词:
Cu(3)Sn;Growth mechanism;Interface;Soldering;Transmission electron;microscopy;solder joints;interfacial reactions;intermetallic growth;reactive;interface;diffusion couples;molten sn;temperature;technology;copper;layers
陈小红
,
刘平
,
毕莉明
,
简发萍
,
刘新宽
,
马凤仓
,
李伟
材料热处理学报
对大变形制备的Cu-Cr原位复合材料的相界面进行HRTEM分析.结果表明:在Cu/Cu界面观察到两种界面衬度,即完全共格和错配位错衬度；Cu/Cr界面观察到完全共格和波纹图衬度.且发现在应变量η=6.43时,Cu/Cr界面中的Cr侧通过晶内畸变位错调节与基体的应变差异,保持界面的共格状态.
关键词:
Cu-Cr原位复合材料
,
相界面
,
HRTEM
杨杨
,
李正华
,
程信林
,
朱筱北
,
裴大荣
,
高文柱
稀有金属材料与工程
用爆炸复合的方法,试制出了Cu/Mo/Cu板材.用光学显微镜和扫描电镜研究了其界面组织特征; 并利用显微硬度考察了界面附近硬度及界面附近的形变特点.结果表明:Cu/Mo/Cu复合材具有波形结合面和平直结合面;波形界面存在熔区,其熔区的显微硬度高于Cu基体而低于Mo基体.
关键词:
Cu/Mo/Cu
,
界面
,
爆炸复合
,
组织特征
Journal of Biomedical Materials Research Part A
The Porous materials of Cu and Ag/CLI were successfully prepared by the electrodeposition on a precursor of conventional polyamide foam. The microstructure of the porous materials was observed by scanning electron microscope. Their porosity and specific Surface area were measured. The inhibition effect of Cu porous materials against E. coli was also investigated. The broad-spectrum of antibiosis of the Cu and Ag/Cu porous materials were characterized. The corrosion resistance of Cu, Ag/CLI coatings was also compared. The shape and size of pores are uniform in three directions for the porous materials. Their porosity may reach above 95%, and specific Surface area is beyond 12.8 m(2)/m(3). The antibacterial test results show that the Cu porous materials not only exhibited high antibacterial effect and good broad-spectrum antibacterial properties, but also excellent persistent antibacterial effects; the antibacterial effects, and broad-spectrum of antibiosis were greatly improved through the deposition of a thin Ag coating on the surface of Cu porous material. (C) 2007 Wiley Periodicals, Inc.
关键词:
porous material;antibacterial properties;Cu;Ag/Cu;corrosion;resistance;silver ions;catheter;behavior;copper
Journal of Adhesion Science and Technology
Multilayered Cu coatings were successfully obtained by introducing periodic ultrasonic agitation into an ordinary electroplating process. A so-called bidirectional bending test technique was proposed to assess the adhesive performance of electroplated Cu coatings to a substrate, in which the coated sample was bent in two directions, while the changes in the coating surface were observed. The critical cycle number for the sample, which corresponds to the start of detachment of the coating from the substrate, proved to be suitable for assessing the adhesion. A comparative study showed that the multilayered Cu coatings produced in this work, had much better adhesion than did ordinary Cu coatings. (C) Koninklijke Brill NV, Leiden, 2012
关键词:
Multilayered Cu coatings;adhesion performance;bidirectional bend test;periodic ultrasonic wave;the critical cycle number;single
Journal of Electronic Materials
We have performed density functional theory calculations to examine the role of Bi impurities in modifying the structure and properties of the Cu/Cu(3)Sn(100) interface. Analysis of the heat of supercell formation reveals that Bi atoms preferentially replace Cu atom in the Cu slab. Substitution of Cu by Bi reduces the adhesion energy of the interface from 1.5 J/m(2) to 1.1 J/m(2), primarily due to the atomic size effect. The size effect leads to expansion of the interface, because surrounding Cu and Sn atoms are pushed away from the misfit Bi atoms. Analysis of electronic density indicates that the local charge density is dispersed around Bi atoms. The presence of a Bi atom makes surrounding atoms less active, which is attributed to the reduction of hybridizations.
关键词:
DFT;bismuth;impurity;interface;bonding;solder interconnect;molecular-dynamics;bismuth solder;embrittlement;joints;copper;cu3sn;pseudopotentials;segregation;fracture
