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Introduction to atmospheric corrosion research in China

Science and Technology of Advanced Materials

In this paper, we introduce the research on atmospheric corrosion in China. We describe the climate characteristics and the classification of atmospheric corrosivity across the whole country. We also describe the rusting evolution under simulated wet/dry cyclic conditions. (C) 2007 NIMS and Elsevier Ltd. All rights reserved.

关键词: atmospheric corrosion;corrosivity;rusting evolution;weathering steels;rust;mechanism;so2;o-3;no2

R&D STATUS ON INTERMETALLICS IN CHINA

CHEN Guoliang(State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 , China)SHI Changxu (Academia Sinica , Beijing 100864 , China)

金属学报(英文版)

This paper briefiy introduces the R&D of intermetallics in China. R&D on intermetallics in a national scale in China began near ten years ago. The investigation in past years focused on the fundamental research and materials development. A significant progress has been made. Various components that made of Ti3Al Ni3Al, TiAl and Fe3Al have been successfully manufactured Some of them have been evaluted. It is expected that some intermetallic alloys will be produced in an industrial scale in the near future.

关键词: :intermetallic alloys , null , null , null

Key R&D activities for development of new types of wrought magnesium alloys in China

Transactions of Nonferrous Metals Society of China

Many researchers in China are actively engaged in the development of new types of wrought magnesium alloys with low cost or with high-performances and novel plastic processing technologies. The research activities are funded primarily through four government-supported programs: the Key Technologies R&D Program of China, the National Basic Research Program of China, the National High-tech R&D Program of China, and the National Natural Science Foundation of China. The key R&D activities for the development of new wrought magnesium alloys in China are reviewed, and typical properties of some new alloys are summarized. More attentions are paid to high-strength wrought magnesium alloys and high-plasticity wrought magnesium alloys. Some novel plastic processing technologies, emerging in recent years, which aim to control deformation texture and to improve plasticity and formability especially at room temperature, are also introduced.

关键词: wrought magnesium alloy;microstructure;properties;alloy designing;plastic deformation;research projects;y-zr alloys;mechanical-properties;mg-4y-4sm-0.5zr alloy;grain-refinement;rare-earth;microstructure;gd;phase;temperature;evolution

Recent developments in high temperature intermetallics research in China

Intermetallics

A comprehensive survey was made of various advances of intermetallics research in China. The investigation focussed on the fundamental research and materials development. Charge density distribution and site occupancy of alloying elements, environmental embrittlement and chemical reaction, interface structures and phase transformation at the atomic scale, nanocrystalline intermetallics and its thermal stability, superplastic behavior and anomalous yield strength peak are reviewed. Several Ti-Al and Ni-Al based alloys have been manufactured, and show good mechanical properties. Diverse components have been fabricated successfully. (C) 2000 Elsevier Science Ltd. All rights reserved.

关键词: aluminides, miscellaneous;hydrogen embrittlement;mechanical properties;at high temperatures;superplastic behavior;phase interfaces;grain-boundary fracture;in-situ composites;environmental;embrittlement;hydrogen embrittlement;ni3al;compression;alloys;co3ti;boron;feal

The effect of grinding on the sintering of raw petroleum coke

Carbon

Preparation of dense carbon materials without use of any binder was attempted, effect of grinding treatment on the characteristics of raw petroleum needle coke and on the properties of the sintered carbon compacts was investigated, and the sintering mechanizm of the coke after grinding was discussed. It was found that the coke particle size and crystalline size was decreased and the specific surface area of the coke was increased with grinding, and the influence was obvious up to 20 hours grinding treatment. The interlayer spacing of the coke after graphitization at 2773 K was gradually increased and the a-axis constant was marginally reduced with the grinding time. Results from the sintering experiment show that carbon materials can be sintered from the ground coke, and the density and flexural strength of the sintering compacts reached stable values of 1.8 g cm(-3) and about 70 MPa, respectively, after 20 hours grinding of the coke. The sintering ability of the coke after grinding was considered to result from the increase of surface energy, lattice distortion energy and fraction of volatile matters of the coke, which were induced by grinding treatment. (C) 1997 Elsevier Science Ltd

关键词: needle coke;semicoke;baking;mechanical properties;particle size;graphite

Spatial variability of soil resistivity and rational sampling for corrosion assessment of carbon steel in Daqing area

Liangshan QU

金属学报(英文版)

Soil resistivity is one of the key indicators of the corrosive classification assessment on metal materials in soil environment. This paper presents variance characters of various quantity of soil resistivity samples data based on the semi-variance function methods of Geo-statistical Analysis by analyzing the regional soil resistivity sampling data in Daqing area. Furthermore, the variance of the soil resistivity as well as entire soil circumstance due to different sampling amounts are also analyzed and compared by means of using the characteristic parameters of the semi-variance function. In addition, this work also studied the rational sampling quantities according to various measurement errors required and evaluated the local soil corrosivity on carbon steel based on the actual measuring data in this area.

关键词: Soil resistivity , spatial variability , sampling

(alpha-PbO2-type nanophase of TiO2 from coesite-bearing eclogite in the Dabie Mountains, China

American Mineralogist

A natural high-pressure phase of titanium oxide with alpha-PbO2-structure has been found in omphacite from coesite-bearing eclogite at Shima in the Dabie Mountains, China. High-resolution transmission electron microscope observations have revealed an orthorhombic lattice, corresponding to alpha-PbO2-type TiO2, with cell parameters a = 0.461 nm, b = 0.540 nm, c = 0.497 nm and space group Pbcn. It occurs as nanometer-thick (< 2 nm) lamellae between multiple twinned rutile crystals, providing additional evidence of very high-pressure, metamorphism at 7 GPa, 900 degrees C. This implies subduction of continental material to a depth of more than 200 kilometers. alpha-PbO-type TiO2 could be an extremely useful index mineral for ultrahigh-pressure.

关键词: high-pressure phase;ries crater;rutile;polymorph;titanium

TEM and HRTEM study of microstructures in omphacite from UHP eclogites at Shima, Dabie Mountains, China

Acta Geologica Sinica-English Edition

Transmission electron microscope (TEM) and high resolution transmission electron microscope (HRTEM) analyses have been performed on omphacite from ultra-high pressure (UHP) eclogites at the locality of Shima, Dabie Mountains, China. TEM reveals that the microstructures consist dominantly of dislocation substructures, including free dislocations, loops, tiltwalls, dislocation tangles and subboundaries. They were produced by high-temperature ductile deformation, of which the main mechanism was dislocation creep. Antiphase domain (APD) boundaries are common planar defects; an age of 470 +/- 6 Ma for UHP eclogite formation has been obtained from the equiaxial size of APDs in ordered omphacites from Shima, coincident with ages given by single-zircon U-Pb dating (471 +/- 2 Ma). HRTEM reveals C2/c and P2/n space groups in different parts of one single omphacite crystal, and no exsolution is observed in the studied samples, which is attributed to rapid cooling. It is suggested that the UHP eclogites underwent a long period of annealing at high temperatures, followed by relatively rapid cooling. These data provide valuable information for the formation and exhumation mechanism of UHP eclogites in the Dabie high-pressure (HP) and UHP metamorphic belt.

关键词: UHP eclogite;omphacite;TEM and HRTEM;Dabie mountains;high-temperature deformation;naturally deformed omphacites;diopside;single-crystal;dislocation glide;transformation;consequences;mechanisms;rocks;shan

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