Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing
A lot of non-equilibrium high technologies have recently been developed in materials processing, such as spray forming; metal atomization by electric fluid dynamics; self-propagating high temperature synthesis; in situ contact reaction process in melt for making composites and electropulsing effect on structure modification and damage reversal etc. A series of non-equilibrium thermophysical problems arise consequently with these high technologies. Not only the real-time measurements are difficult to deal with, but also the principle analyses need to be treated carefully. It would be found that some of the normal thermophysical rules should be evaluated again, when the thermophysical processes under extreme conditions are further studied. Some possible ways for solving these abnormal thermophysical problems are tentatively suggested in this paper, such as the reconstruction of governing functions; the simplified treatment of complex processes and making use of the rules of other disciplines etc. It is known from these examples that a series of non-equilibrium thermophysical problems arising from recent high technologies of materials processing are remained to be actively studied. It gives a virgin land for thermophysicists to explore. (C) 2000 Elsevier Science S.A. All rights reserved.
关键词:
biomimetic;materials processing;non-equilibrium;thermophysical;problems
Haiping XIA
,
Zhaoyang JIANG
,
Jianli ZHANG
,
Jinhao WANG
,
Yuepin ZHANG
,
Qiuhua NIE
材料科学技术（英文）
Water soluble fullerenols were synthesized and incorporated in SiO2, SiO2-TiO2, GPTMS- SiO2, GPTMS-ATPS inorganic and organic-inorganic materials by sol-gel processes. The maximum concentrations of C60 (OH) n and C70 (OH) n in the obtained SiO2 gels were estimated to be about 0.6% and 1.5% in weight, respectively. The characteristics of the UV/visible spectra of fullerenols in H2O and various gels were measured and compared. The thermal stability of fullerenols in gels was investigated with differential thermal analysis (DTA). The results indicate that the absorption features of fullerenols in solid gels are similar to those in H2O and the fullerenols in SiO2 are stable at 400ºC. The optical limiting effect of the fullerenols was investigated preliminarily.
关键词:
Water soluble fullerenol
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null
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null
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null
杨金瑞
,
余尚先
,
顾江楠
高分子材料科学与工程
通过对resol(羟甲基酚化合物和低分子量羟甲基酚树脂)DEPT135图谱的分析讨论,得到一系列计算resol微细结构参数的经验公式.根据DEPT135图谱可判断是否发生缩聚反应,根据经验公式可计算酚单体各个活性点参与反应百分率或酚羟基导入率、不同类型缩聚所占百分率及低分子量羟甲基酚树脂的平均核体数.
关键词:
羟甲基酚化合物
,
羟甲基酚树脂
,
DEPT135
,
结构参数
Metallurgical and Materials Transactions a-Physical Metallurgy and Materials Science
Friction stir processing (FSP), developed based on the basic principles of friction stir welding (FSW), a solid-state joining process originally developed for aluminum alloys, is an emerging metalworking technique that can provide localized modification and control of microstructures in near-surface layers of processed metallic components. The FSP causes intense plastic deformation, material mixing, and thermal exposure, resulting in significant microstructural refinement, densification, and homogeneity of the processed zone. The FSP technique has been successfully used for producing the fine-grained structure and surface composite, modifying the microstructure of materials, and synthesizing the composite and intermetallic compound in situ. In this review article, the current state of the understanding and development of FSP is addressed.
关键词:
strain-rate superplasticity;cast nial bronze;al-mg-zr;low-temperature;superplasticity;nickel-aluminum bronze;particle-size ratio;mechanical-properties;microstructural modification;magnesium alloy;grain-refinement
Materials Chemistry and Physics
Some progress in the biomimetic design and processing of composite materials has been achieved on the basis of biomimetic analyses. The excellent structures and characteristics of biomaterials, such as adapting to stress conditions by form modulation, compensating for lacking material by composite structures, and healing injuries by material and energy supplements, are analyzed. Some examples of biomimetic design and processing are further illustrated: multilayer coating simulating the fine structure of plant fibers; dumbbell-like whiskers imitating animal bone; fractal-tree reinforcement by mimicry of branched roots in soil; biomaterial reinforcement and its modification; and fatigue-crack healing and lifetime prolongation of materials. The methodology of biomimetic study is described briefly in the last part of this paper.
关键词:
composites;biomimetic design and processing;fractal-tree structure;crack healing;fibers
G.Q. Zhang
金属学报(英文版)
The status of research, development of superalloys and materials processing & fabrication technologies for aero-engine applications in China Aviation Industry, with an emphasis on recent achievements at BIAM including directionally solidified and single crystal superalloys for blade and vane applications, wrought superalloys for aero-engine disks and rings, and powder metallurgy (PM) superalloys for high performance disk applications were described. It was also reviewed the development of new class of high temperature structural materials, such as structural intermetallics, and advanced material processing technologies including rapid solidification, spray forming and so on. The trends of research and development of the above mentioned superalloys and processing technologies are outlined. Cast, wrought and PM superalloys are the workhorse materials for the hot section of current aero-engines. New high temperature materials and advanced processing technologies have been and will be the subject of study. It is speculated that high performance, high purity and low cost superalloys and technologies will play key roles in aero-engines.
关键词:
superalloy
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null
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null
