SUN Dongsheng LI Fengzhao ZHANG Gang Shandong Polytechnic University
,
Jinan
,
China Lecturer
,
Centre of Materials Testing and Analysis
,
Shandong Polytechnic University
,
Jinan 250014
,
China
金属学报(英文版)
Cryogenic strength,ductility and toughness of AI-Li alloy 8090 were found to be superior to those at ambient temperature,and up to optima at about 20 K.Different aging regimes may only influence on its cryogenic yield strength and elongation.
关键词:
Al-Li alloy
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null
,
null
,
null
Journal of University of Science and Technology Beijing
The failure of a fluid catalysis and cracking unit (FCCU) in a Chinese refinery was investigated by using nondestructive detection methods, fracture surface examination, hardness measurement, chemical composition and corrosion products analysis. The results showed that the failure was caused by the dew point nitrate stress corrosion cracking. For a long operation period, the wall temperature of the regenerator in the FCCU was below the fume dew point. As a result, an acid fume NOx-SOx-H2O medium presented on the surface, resulting in stress corrosion cracking of the component with high residual stress. In order to confirm the relative conclusion, simulated testing was conducted in laboratory, and the results showed similar cracking characteristics. Finally, some suggestions have been made to prevent the stress corrosion cracking of an FCCU from re-occurring in the future.
关键词:
stress corrosion cracking;fluid catalytic cracking unit;dew point;failure
Minh-Quy LE
,
Seock-Sam KIM
材料科学技术（英）
Finite element analysis was carried out to investigate the conical indentation response of elastic-plastic solids within the framework of the hydrostatic pressure dependence and the power law strain hardening. A large number of 40 different combinations of elasto-plastic properties with n ranging from 0 to 0.5 and σy/E ranging from 0.0014 to 0.03 were used in the computations. The loading curvature C and the average contact pressure pave were considered within the concept of representative strains and the dimensional analysis. Dimensionless functions associated with these two parameters were formulated for each studied value of the pressure sensitivity. The results for pressure sensitive materials lie between those for Von Mises materials and the elastic model.
关键词:
Finite element analysis
,
null
,
null
,
null
Hongsheng DING
,
Jun JIA
,
Jingiie GUO
,
Yanqing SU
,
HengZhi FU
,
Jinshan LI
材料科学技术（英）
A thermodynamic model has been built up for the interactions between molten Ti alloys and oxide molding materials in the way of decomposition and solution of molding materials, then the influences on the reaction free energy changes have been calculated and discussed.
关键词:
Journal of Materials Science
A procedure for modeling effects of surface stress relaxation in specimens processed from materials with residual strains was described at first, then the anisotropic finite element analysis was performed to study characteristics of strain relaxation in the cross-sectional specimens of strained-layer materials. By using the "element death" technique, the finite element model of the specimen was separated from the finite element model of the bulk material, and a free surface was created. As a result, effects of surface stress relaxation during processing specimens were conveniently modeled. The finite element results about strain relaxation in the cross-sectional specimens of GexSi1-x/Si superlattice were presented. Characteristics about the shear strain near the interface, the strain normal to the surface, and the strain normal to the interface were studied. (C) 2000 Kluwer Academic Publishers.
关键词:
beam electron-diffraction;elastic relaxation;deformed copper;single-crystal;microscopy;stress;heterostructures
材料科学技术（英）
Applying the concept of multirange fractals, a new explanation to the Williford's multifractal curve on the relationship of fractal dimension with fracture properties in materials has been given. It shows the importance of factorizing out the effect of fractal structure from other physical causes and separating the appropriate range of scale from multirange fractals.
关键词:
M. Sakane (Department of Mechanical Engineering
,
Faculty of Science and Engineering
,
Ritsumeikan University
,
1-1-1Nojihigashi Kusatsu-shi Shiga
,
525-8577
,
Japan)S. Mukai (Power Reactor and Nuclear Fuel Development Corporation
,
4002 Narita-cho Oarai-cho Ibaragibun Ibaragi
,
311-13
,
Japan)
金属学报(英文版)
This paper describes new methods for biaxial and triaxial creep testing. Biaxial tension and triaxial tension creep testers were developed. The performance of the machines was described and some test results were discussed. Stress biaxiality had almost no effect on the creep deformation and Mises potential was suitable for describing the creep deformation under biaxial and triaxial stress states. Stress biaxiality had a small influence on prolonging creep rupture time under the constant Mises stress condition.A new triaxial tension creep testing method was discussed together with the shape of the triaxial creep specimen.
关键词:
creep
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null
,
null
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null
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null
Jom-Journal of the Minerals Metals & Materials Society
Composite materials employ both matrix and reinforcement properties to provide high performance, but they are difficult to design. Biomaterials in nature are composites that provide inspiring examples of completeness and efficiency. Biomimetic analyses and biomimetic design and testing are a new direction in the study of composite materials, In this article, several examples show how biomimetic methods can significantly improve material properties.
关键词:
fracture-toughness;fibers
