ZENG Xianghua
,
SHA Jiande
,
SU Ge Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
ChinaYUAN Jigang LIU Fumei ZHONG Huiwen Southwest Aluminium Mill
,
China National Nonferrous Metals Industry Corporation
,
Chongqing
,
China SHA Jiande
,
Engineer
,
Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
China
金属学报(英文版)
The end grain attack of LDIOCS aluminium alloy plates during chemical milling in hot aqueous solution of sodium hydroxide has been studied.The results show that the microsegregation of some components,i.e.Cu,Si etc.,is the main reason of the end grain at- tack,and it is affected by the conditions of heat treatment as well.The end grain attack significantly diminishes while some technical measures which are beneficial to the reduce of segregation were taken during melting and casting.
关键词:
aluminium alloy
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null
,
null
,
null
Guoxin SUI Zhongguang ZHENG Chengti ZHOU Changxu SHI Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
110015
,
ChinaBenlian ZHOU International Centre for Materials Physics
,
Academia Sinica
,
Shenyang
,
110015
,
China
材料科学技术(英文)
A new kind of superhybrid composite material,vinylon reinforced aluminium laminate (VIRALL),has been developed by laminating the vinylon/epoxy prepreg layers and the aluminium alloy sheets alternatively.The mechanical properties of VIRALL laminate have been tested and the results are dis- cussed in terms of laws of mixtures.About a 24% increase in tensile strength and a 36%decrease in tensile modulus to that of the corresponding aluminium were found,which kept good agreement with the laws of mixtures.Compared with the corresponding aluminium,VIRALL has lighter density and lower price.VIRALL is hoped to be a partial substitute for the civil aluminium alloy in the future.
关键词:
composite material
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null
,
null
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null
,
null
,
null
LIU Wei
,
WANG Zhongguang
,
XIA Yuebo Institute of Matal Research
,
Academia Sinica
,
Shenyang
,
China.
材料科学技术(英文)
In order to understand the basic mechanism of intergranular cracking in pure metals during fatigue, stress-controlled push-pull fatigue tests were carried out with high purity aluminium. Tests were interrupted frequently so as to study the grain boundary (GB) cracking behaviour by the surface observation. The results show that crack initiation at GB was a process controlled by multi-factors, such as boundary structure, GB-slip interaction, GB sliding and so on. If these factors are varied so that the incompati- bility at a GB increased, the possibility of cyacking at the boundary will be raised. Some inteygranular cracking phenomena are not able to be explained by the GB stepping mechanism.
关键词:
intergranular crack
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null
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null
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null
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null
Journal of Materials Science
A super-hybrid (natural composite/fibre-reinforced composite/metal hybridization) ecomaterial, reformed bamboo/glass fabric/aluminium (RB/GF/Al) was developed. The addition of a sparse glass fabric/epoxy resin layer between reformed bamboo and aluminium proved to be effective in increasing the compressive, tensile strength of the composite material. In particular, the interfacial shear strength between the reformed bamboo and aluminium was improved, and was the transverse tensile strength. These were the major shortcomings of normal bamboo and reformed bamboo/aluminium composites. The good recyclability of reformed bamboo and aluminium make RB/GF/Al an environmentally friendly material. Extensive use of such an ecomaterial instead of wood would save natural forest resources. (C) 1998 Chapman & Hall.
关键词:
ZHANG Qiyun LIU Shuqi LAN Tie FU Yuchuan Peking University
,
Beijing
,
China ZHANG Qiyun
,
Professor
,
Department of Chemistry
,
Peking University
,
Beijing
,
China
金属学报(英文版)
A study on the interfacial activity behavior of flux during aluminium brazing has been made by using metallography,SEM and electron prob techniques.The results show that the activity, of a flux is caused by the wetting of base metal with the liquid heavy metal reduced from the flux,thus,some regions of liquid alloy created,at which no aluminium oxide film covers on the surfaces.The reduced metal drops are finally trapped in the fillet.The size of the metal drops increases with the decrease of brazing temperature.
关键词:
aluminium brazing
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null
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null
Journal of Physics-Condensed Matter
High resolution transmission electron microscopy (HRTEM) observations show evidence for the formation of disorder Al zones around some faceted Pb inclusions embedded in an Al matrix in immiscible lead-aluminium samples, which were prepared by a melt-spun method and then aged for about two months at room temperature. Furthermore, it is found that, both before and after ageing, all such Pb inclusions have a cube-cube orientation relationship with the Al matrix. The results of molecular dynamics (MD) simulations give an extensive analysis of the formation of the disorder Al zones and provide a reasonable explanation for the HRTEM finding: the existence of oxygen soluted in the Pb inclusions at higher temperatures may lead to the formation of the disorder Al zone in the aged sample. The dependence of the thickness of the disorder Al zone on the amount of oxygen soluted in the Pb inclusion at higher temperatures, and the average stress in the equilibrium configuration of a MD cell, is discussed.
关键词:
solid-state reaction;y-mo system;heterogeneous nucleation;structural;relaxation;al;pb;inclusions;alloys;solidification;potentials
Acta Materialia
The transformations of dipoles of dissociated edge dislocations in aluminium are investigated using molecular dynamics for dipole heights ranging from one to ten {111} interplanar distances and at temperatures up to 900 K. Three types of configurations, hollow, vertical compact and inclined dipoles, are considered and their relative stabilities compared. Hollows are unstable at finite temperature. Dipoles neither annihilate nor form stable hollow cores but transform into height- and temperature-dependent layouts including cores containing ordered free Volumes, zigzag faulted dipoles and agglormerated truncated stacking fault tetrahedra (SFT). Small individual SFT are formed at the highest temperatures, attesting to short-range pipe diffusion. These rearranged configurations are strong obstacles to mobile dislocations, thence potential nucleation sites for dislocation entanglement and self-patterning under single slip. A new thermally activated mechanism of SFT formation directly from vacancy clusters resulting from local dipole pinching-off is reported. (C) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
关键词:
Dislocation dipole;Annihilation;Stacking fault tetrahedron;Molecular;dynamics simulations;Reordering;stacking-fault tetrahedra;nickel single-crystals;molecular-dynamics;fcc metals;dissociated dislocations;interatomic potentials;room-temperature;weak-beam;slip;al