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ON THE ORDERING TRANSFORMATIONS IN Ti_3AL-Nb ALLOY

LI Dong ZHOU Jing CHANG Xin GUAN Shaoxuan Institute of Metal Research , Academia Sinica , Shenyang , China

金属学报(英文版)

Study was made of the behaviour of ordering transformation in Ti_3AI-Nb alloy,including the ordering at high temperatures,the transformation of high temperature β-phase during cooling,and the decomposition of metastable β-phase during aging.The results show that the ordered primary α_2 and high temperature β in alloy form at 1060℃.The transformation of high temperature β-phase proceed by β→α_2+ω type during cooling,and the decomposition of metastable β and ω type proceeded by(β+ω)_(metustabte)→(α_2+β)_(stable)during aging at 700℃.

关键词: Ti_3Al-Nb alloy , null , null , null , null

A special structure in Al-Mg-Li alloy (01420) weld metal

材料科学技术(英文)

A large quantity of laminated fine grain zones were observed in the Al-Mg-Li alloy weld metal by manual TIG, which was not found in ordinary Al alloy welds. The fine grain zone is formed because of the Al-3(Zr,Ti) particles in the filler metal and the manual filling of filler metal in welding process.

关键词:

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

Catalytically enhanced dehydrogenation of Li-Mg-N-H hydrogen storage material by transition metal nitrides

Journal of Alloys and Compounds

Motivated by the understanding of dehyrogenation/rehydrogenation reaction mechanisms, we examine the effect of two commercial transition metal nitrides. TaN and TiN, oil the dehydrogenation performance of Li-Mg-N-H system. Both nitrides are catalytically active for accelerating the dehydrogenation reaction of this system. Such catalytic enhancement well persists without hydrogen capacity loss. A catalytic mechanism is proposed Willi reference to the catalytic, model for hydrotreating reactions by transition metal nitrides. (c) 2008 Elsevier B.V. All rights reserved.

关键词: Hydrogen absorbing materials;Nitride materials;molybdenum nitride;system;improvement;catalysts;mechanism;mixtures;hydride;imides;amide;linh2

Technical note: Research and development of localized corrosion rate monitoring instrument for nonpassivable metal in corrosive media

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

Effect of crystallinity on electrochemical insertion/extraction of Li in transition metal oxides - Part II: TiO2, V2O5 and MoO3

Tomoki TSUMURA , Michio INAGAKI

材料科学技术(英文)

Electrochemical insertion/extraction sf Li on cathode materials of anatase type TiO2, quasi-layered structure V2O5 and layered structure MoO3 was measured on samples of which structures were well characterized and showed a wide range of crystallinity. On the basis of experimental results on structure, morphology and charge-discharge characteristics, the effect of crystallinity of the cathode materials on electrochemical Li insertion/extraction performance was discussed. These three transition metal oxides were classified as one group on the basis of whether the crystallinity of these oxides affects to the performance or not, LiMn2O4 and LiCo0.5Ni0.5O2 belongs to the former group and TiO2, V2O5 and MoO3 to the latter.

关键词:

Study on Process Parameters Optimization of Sheet Metal Forming Based on PFEA/ANN/GA

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

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