Yuxiong LU
,
Douxing LI
,
Dehai PING
,
Jing BI and Zongyi MA (Institute of Metal Research
,
Chinese Academy of Sciences
,
Shenyang 110015
,
China)
材料科学技术（英文）
The composite of Ti matrix with TiB whisker reinforcement has been successfully fabricated. The content of TiB whisker in Ti matrix can reach about 30 vol. pct. Metallographic examination,morphology and microstructure of TiB whisker, interface structure between TiB whisker and Ti matrix were investigated using optical microscope, SEM, TEM and HREM technology. The diameter distribution of TiB whisker is from 0. 1 μm to 3.5 μm and the aspect ratio of TiB whisker is from 10 to 20. The cross-section of whisker is generally polygon. Because of good compatibility between TiB whisler and Ti matrix it is identified that there is no obvious interaction of Ti matrix with Ti B reinforcement and TiB whisker reinforced Ti matrix composites have excellent elevated properties.
关键词:
MA Zongyi YAO Zhongkai Harbin Institute of Technology
,
Harbin
,
China
金属学报(英文版)
The SiC_w/Al composite prepared by squeeze casting has a combination of superior room temperature specific strength and modulus together with excellent thermal properties.The extrusion can make an improvement on the strength and ductility of the composite from 582 MPa as squeeze casted up to 639 MPa,and on the transformation from isotropic to the anisotropic structure.This seems to be explained by the orientation of whiskers and the densification of dislocations in matrix.TEM observation indicates that the stacking fault is the usual planar defect on the SiC_w surface. composite;;SiC whisker;;Al alloy;;microstructure
关键词:
composite
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null
,
null
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null
Corrosion
This paper introduces the design of a localized corrosion rate monitoring instrument that can monitor and evaluate the maximum and stable localized corrosion rate of a nonpassivable metal in a corrosive environment by measuring the current density in a corrosion sensor with an occluded anode.
关键词:
instrument;localized corrosion rate;monitor
李佳
,
张忻
,
路清梅
,
张久兴
,
卫群
功能材料
机械合金化与放电等离子烧结技术(SPS)相结合制备了p型(Bi,Sb)2Te3合金块体.在300～423K的温度范围内测试了样品的电导率﹑Seebeck系数和热导率.系统研究了球磨时间对合金化与热电性能的影响.球磨2h的样品具有最低的热导率,因此其ZT值最高,在323K时为1.16,在373K达到最大值1.23.
关键词:
热电材料
,
机械合金化
,
放电等离子烧结(SPS)
Juhua HUANG
,
Jinjun RAO
,
Xuefeng LI
材料科学技术（英文）
Sheet metal forming is widely applied to automobile, aviation, space flight, ship, instrument, and appliance industries. In this paper, based on analyzing the shortcoming of general finite element analysis (FEA), the conception of parametric finite element analysis (PFEA) is presented. The parametric finite element analysis, artificial neural networks (ANN) and genetic algorithm (GA) are combined to research thoroughly on the problems of process parameters optimization of sheet metal forming. The author programs the optimization scheme and applies it in a research of optimization problem of inside square hole flanging technological parameters. The optimization result coincides well with the result of experiment. The research shows that the optimization scheme offers a good new way in die design and sheet metal forming field.
关键词:
Sheet metal forming
,
null
,
null
,
null
J.Q.ZHANGD.J.YOUNG
中国腐蚀与防护学报
Metaldusting attacks iron, low and high alloy steels and nickel-or cobalt-base alloys by disintegrating bulk metals and alloys into metal particles in a coke deposit. It occurs in strongly carburising gas atmospheres (carbon activity aC>1) at elevated temperatures (400 ℃~1000 ℃). This phenomenon has been studied for decades, but the detailed mechanism is still not well understood. Current methods of protection against metal dusting are either directed to the process conditions-temperature and gas composition-or to the development of a dense adherent oxide layer on the surface of the alloy by selective oxidation. However, metal dusting still occurs by carbon dissolving in the base metal via defects in the oxide scale. The research work at UNSW is aimed at determining the detailed mechanism of metal dusting of both ferritic and austenitic alloys, in particular the microprocesses of graphite deposition, nanoparticle formation and underlying metal destruction. This work was carried out using surface observation, cross-section analysis by focused ion beam and electron microscopic examination of coke deposits at different stages of the reaction. It was found that surface orientation affected carbon deposition and metal dusting at the initial stage of the reaction. Metal dusting occurred only when graphite grew into the metal interior where the volume expansion is responsible for metal disintegration and dusting. It was also found that the metal dusting process could be significantly changed by alterations in alloy chemistry. Germanium was found to affect the iron dusting process by destabilising Fe3C but increasing the rate of carbon deposition and dusting, which questions the role of cementite in ferritic alloy dusting. Whilst adding copper to iron did not change the carburisation kinetics, cementite formation and coke morphology, copper alloying reduced nickel and nickel-base alloy dusting rates significantly. Application of these fundamental results to the dusting behaviour of engineering alloys is discussed.
关键词:
metal dusting
,
null
,
null
,
null
,
null
,
null
Z. Yang
,
J.P. Li
,
J.X. Zhang
,
G.W.Lorimer
,
J. Robson
,
null
,
null
,
null
,
null
金属学报(英文版)
The current research and development of magnesium alloys is summarized. Several aspects of magnesium alloys are described: cast Mg alloy, wrought Mg alloy, and novel processing. The subjects are discussed individually and recommendations for further study are listed in the final section.
关键词:
Magnesium alloys
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null
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null
