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Protective Characteristics and Formation Mechanism of the Corrosion Product Films of B30 Tubes Exposed to Seawater

ZHU Xiaolong LIN Leyun Surface Technology Center , General Research Institute for Nonferrous Metals , Beijing , 110083 , ChinaTo whom correspondence should be addressed

材料科学技术(英)

The corrosion product films of two kinds of B30 tubes(similar to CDA 715)exposed to seawat- er for various periods of time were investigated by SEM,AES and XPS.The results show that the pro- tective corrosion product film is thin,uniform and adherent.FeOOH is found to be present in the film surface,which confirms the hypothesis that iron hydroxide segregates at the surface of the film.The FeOOH promotes Ni enrichment in the corrosion layer by preventing Ni from running off.The corro- sion product film with no protectiveness is of lay- ered structure,loose and bad adherence.The for- mer film is formed through direct oxidation and the latter by precipitation and redeposition from dis- solved species.

关键词: Cu-Ni alloy , null , null

Structural refinement and deformation mechanisms in nanostructured metals

Scripta Materialia

Deformation mechanisms in metals deformed to ultrahigh strains are analyzed based on a general pattern of grain subdivision down to structural scales similar to 10 nm. The materials analyzed are medium- to high-stacking fault energy face-centered cubic and body-centered cubic metals with different loading conditions. The analysis points to dislocation glide as the dominant deformation mechanism at different length scales supplemented by a limited amount of twinning at the finest scales. With decreasing deformation temperature and increasing strain rate, the contribution of twinning increases. (C) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

关键词: Deformation mechanisms;Nanostructured metal;Twinning;Structural;refinement;Plastic deformation;dynamic plastic-deformation;dislocation-structures;surface;nanocrystallization;microstructural evolution;grain-refinement;copper;nickel;dependence;strains;alloys

Metals Supported Water Monomers: the Bonding Nature Revisited

材料科学技术(英)

A single water monomer is known as a hard-to-observe molecule even in the presence of metal surfaces as supporting matrix. This review highlights effort in experimental characterizations and theoretical modeling of transition metals supported water monomers with attention given to its structure and bonding, together with the insights that we have provided into the bonding nature of the water-interactions by the newly employed projected PDOS (partial density of states) difference analysis, which is proved to be an effective tool to be elucidate such bonding nature. The general s-d hybridization and d-shell effect are summarized, and how these effects can be tuned by tailoring local surface configurations is discussed.

关键词: Water monomer;Adsorption;Surface bonding;Transition metals;density-functional theory;scanning-tunneling-microscopy;oxygen;reduction;electronic-structure;1st principles;slab model;adsorption;surfaces;molecules;h2o

Research on the drawing-up of the pole figure for orientation analysis of directional Si steel sheet

S.H.O

材料科学技术(英)

The magnetic property of soft magnetic metals and alloys depends strongly on the crystallographic orientation. In automated equipment for orientation research. the intensity for drawing up the pole figure is measured in detail. The present research shows that the accurate pole figure can be drawn up without measuring concretely the intensity. For directional Si steel sheet the measuring step may be 4 similar to 5 degrees. In this paper the experimental equation for defocusing correction was derived from the experimental data in different specimens with random orientation.

关键词:

Nanocrystal Model for Liquid Metals and Amorphous Metals

X.L. Tian C.W. Zhan J.X. Hou X.C. Chen J.J. Sun

材料科学技术(英)

A nanocrystal model for liquid metals and amorphous metals has been developed. With the nanocrystal model, the broadening peak profiles (BPPs) of Cu, Al, Al65Cu20Fe15 alloy, Cu70Ni30 alloy and Fe50Si50 alloy were gained by broadening the X-ray diffraction (XRD) peaks of a crystal lattice. By comparing the BPPs with the XRD intensity curves measured on the liquid metals, it is found that the BPPs are closely in agreement with the XRD intensity curves, respectively, except the Fe50Si50 alloy. Therefore, the nanocrystal model can be used to determine if the atomic cluster structure of the liquid metal is similar to the structure of its crystal lattice.

关键词: Liquid metal , Atomic Cluster , Structure , Crystal Lattice

MICROSTRUCTURE AND PROPERTIES OF SiC_w/6061Al COMPOSITE The Author is now with Institute of Metal Research,Academia Sinica,China

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 , null , null , null

A GENERAL-THEORY OF COUPLED LINEAR-RESPONSE OF IMHOMOGENEOUS MEDIA

Chinese Physics Letters

A generally exact theory for predicting the effective behavior of coupled linear-response for inhomogeneous media is developed. The theory can not only give the general results of the effective principal and coupled moduli for the coupled multifield problems, but also provide the interrelationships between these effective moduli. It can be directly employed to describe the coupled two-held or three-held response of any inhomogeneous media.

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