LI Zheng
,
LIU Honglin
,
CHENG Zhaonian
,
CHEN Nianyi
,
Shanghai Institute of Metallurgy
,
Academia Sinica
,
Shanghai
,
ChinaZHOU Jiaju
,
Institute of Chemical Metallurgy
,
Academia Sinica
,
Beijing
,
China CHEN Nianyi
,
Professor
,
Shanghai Institute of Metallurgy
,
Academia Sinica
,
Shanghai 200050
,
China
金属学报(英文版)
The formability of complex flourides has been studied by chemical bond parameter-pattern recognition method. In a multi-dimensional space spanned by ionic radius, ionic polarizability, electronegativity and ionic charge of the metal elements, the binary complex flouride-forming systems and binary flouride systems without complex flouride formation distribute in different regions with a clear-cut boundary. The mathematical models obtained are useful for new complex flouride predicton.
关键词:
complex flouride
,
null
,
null
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
ZHANG Jing
,
CHENG Zhaonian
,
CHEN Nianyi
,
Shanghai Institute of Metallurgy
,
Academia Sinica
,
China CHENG Zhaonian
,
Associate Professor
,
Shanghai Institute of Metallurgy
,
Academia Sinica
,
Shanghai 200050
,
China
金属学报(英文版)
The structure and transport properties in molten NaF have been studied using the method of molecular dynamics simulation. The calculations are based on two models of interionic potentials, which are Fumi-Tosi potential (FT) and the Fumi-Tosi potential without Van der Waals attractive item (FT). The radial distribution function (RDF) and the Na~+ and F~- self-diffusion coefficients have been calculated. The calculated results are in good agreement with the experimental ones. The calculation shows that the two models give nearly identical radial distribution function and self-diffusion coefficient, but the results of FTpotential are a little better than those of FT potential.
关键词:
molten NaF
,
null
,
null
Danyu JIANG
,
Chen ZHANG
,
Jianlin SHI
,
Tingrong LAI and Dongsheng YAN(Shanghai Institute of Ceramics
,
Chinese Academy of Sciences
,
Shanghai 200050
,
China)
材料科学技术（英）
The composite of Dy-α-sialon/10 wt pct nano-size SiC particles has been prepared from precursor powders of Si3N4, AIN, Al2O3, Dy2O3 and nano-size β-SiC. The hardness, toughness and bending strength of the composite at ambient temperature are a little higher than those of Dy-α-sialon.while the bending strength is maintained up to 1000℃ and about 2 times more than that of Dy-α-sialon at the same temperature. The fracture surfaces show that the grain size of the composite is smaller than that of Dy-α-sialon, and both Of them have predominately transgranular mode of fracture. It is believed that the decrease of the bending strength of Dy-α-sialon at elevated temperature is caused by the viscous flow of the grain boundary phase, while the addition of nanosize SiC particles effectively increases the viscosity of the grain boundary phase and therefore prevents the strength loss of Dy-α-sialon/nano-size SiC composites at elevated temperature
关键词:
Z. Wu
,
C.H. Li
,
P. Qin
,
H.L. Liu and N. Y. Chen(Shanghai Institute of Metallurgy
,
Chinese Academy of Sciences
,
Shanghai 200050
,
China)
金属学报(英文版)
A modified Miedema model using four atomic parameters and pattern recognition or artificial neural network has been used to study the factors that affect the entropy of mixing of liquid binary alloy systems. It has been found that the systems with larger electronegativity difference (△Φ) usuallg have negative △Sxs of mixing, while the systems with larger valence electron density difference(denoted by △n) and small △Φ usually have positive △Sxs of mixing. The artificial neural network-atomic parameter method can be used to predict the △Sxs of binary alloy systems consisting of non-transition elements.
关键词:
entropy of mixing
,
null
,
null
Hongchao LIU
,
Changlin KUO (Shanghai Institute of Ceramics
,
Chinese Academy of Sciences
,
Shanghai 200050
,
China)
材料科学技术（英）
In cooperation with figure-of-merits the Rietveld analysis can appraise both angular and intensity data of powder diffraction. In this work, X-ray diffraction pattern of Bi4(SiO4)3 was redetermined with intensity figure-of-merits, which qualify agreement between observed and calculated relative intensities. F30 is 158.90 (0.0059, 32), intensity figure of merit Rint is 8.7, I20(17), 8.0. The values of figure-of-merits show that the data of JCPDS cards are distorted. Both the experimental and calculated peak positions and heights are listed in detail.
关键词:
Zhongming CHEN
,
Shouhong TAN
,
Zhaoquan ZHANG and Dongliang JIANG(Shanghai Institute of Ceramics
,
Chinese Academy of Sciences
,
Shanghai 200050
,
China)
材料科学技术（英）
High performance SiC-AlN composites were fabricated by hot-pressing with Y2O3 as additive via liquid phase sintering. The SiC-AlN composites containing 5 vol. pct AlN exhibit superior mechanical properties with flexural strength, fracture toughness and Vickers hardness of 1131 MPa,6.1 MPa·m1/2 and 28.6 GPa respectively Microstructure observations indicate that the grain size of the composites is obviously inhibited due to the formation of solid solution. TEM-EDS analysis demonstrates the existence of the solid solution. In addition, subgrain boundaries induced by dislocations in the matrix SiC grains, seem to divide a large grain into numerous nano-sized small grains, which significantly increase the mechanical properties of the composites
关键词:
