材料期刊网

STRUCTURAL TRANSFORMATION INDUCED BY MECHANICALLY DRIVEN ALLOYING AND SUBSEQUENT MAGNETIC PROPERLIES OF THE Fe-Cu SYSTEM

Y.Z. Yang , Y.H Luo , Q.S. Li , Y.L. Zhu , X.M. Ma , Y.D. Dong and Y.Z. Chuang(Department of Materials Science and Engineering , Guangdong University of Technology , Guangzhou510090 , China)(Guangdong Educational College , Guangzhou 510084 , China)(Department of Materials Science and Engineering , Shanghai University , Shanghai 200072 , China)(Institute of Metal Research , The Chinese Academy of Sciences , Shenyang 110015 , China)

金属学报(英文版)

The structural transformation in Fe-Cu powder induced by mechanically driven alloying has been monitored by the lattice constant measurements and Mossbauer spectroscopy. For the samples with Cu higher than 75at.% Mossbauer the spectra show a broad paramagnetic doublet; for samples with 50 and 60at.%Cu a new broad ferromagnetic sextet; for those with less than 30at.%Cu similar to those of α-Fe. The main peaks of the hyperfine field distribution significantly broaden and shift to a lower position with increasing Cu content due to the complex environments of iron atoms in the solid solutions and the reduction in the nearest neighbor Fe of a cental Fe atom, respectively. The saturation magnetization of Fe-Cu alloys monotonously decreases with Cu content. The complex composition dependence of coercive field for the milled samples is discussed with respect to the solid dissolution, grain size, interfacial state etc.. The increase of lattice constants with the solute content in the two terminal solid solutions has been explained by the volume-size factor theory or magnetovolume effect.

关键词: mechanical alloying , null , null , null

ATIGUE CRACK GROWTH FEATURE OF Fe-Cr-Ni MATRIX COMPOSITE REINFORCED BY TITANIUM CARBIDE PARTICULATE AT 1023K

Z. F. Wan , X.D. Hui , G.Q. Yuan , Y. S. Yang and X.C Chen (Shandong University of Technology , Jinan 250061 , China)(Institute of Metal Research , The Chinese Academy of Sciences , Shenyang 110015 , China)(Institute of Physics , The Chinese Academy of Sciences , Beijing 100080 , China)

金属学报(英文版)

The initiation and propagation of the short fatigue crack in a 10vol% titanium carbide particulate reichreed cast Fe-26Cr-14Ni mathe coopsite at 1023K were investigated.It is shown that the titanium carbide particulate may hinder the crack propagation and fatigue fracture of the composite. The relationships between fatigue crack propagation rate and stress intensity factor are da/dN=4.2×10-c(△K)4 for the matrix alloy and da/dN=1.4×10-19(△K)c for the composite. The fatigue thresholds of the composite and mathe alloy are 78 and 3.2MPa.m1/2, respectively. Microcracks initiate at the intedece between titanium carbide particulate and austenite and then propagate in carkide particles. The fracture sudece of the composite shows a distinct transition from wavy and serated cleavage near the threshold regime to striation-type splitting in the stable fatigue crack propagation stage and to a veined morphology characteristic in unstable rapid region.

关键词: fatigue crack , null , null , null

~(199)Sn AND ~(57)Fe MOSSBAUER SPECTROSCOPIC STUDY OF THE MECHANICALLY ALLOYED Fe-Sn ALLOYS

Y.Z. Yang , Y.L. Zhu , Q.S. Li , X.M. Ma , Y.D. Dong and Y.Z. Chuang (Department of Materials Science and Engineering , Guangdong University of Technologyt Guangzhou 510090 , China)(Depotment of Materials Science and Engineering , Shanghai University , Shanghai 200072 , China)(Institute of Metal Research , The Chinese Academy of Sciences , Shenyang 110015 , China)

金属学报(英文版)

Nanocrystalline supersaturated solid solutions (Sa in Fe) with Sn content less than 50 at. %,and FeSn2 and Fe1.3Sn intermetallic compounds have been prepared by mechanical alloying of Fe and Sn mixture powders with composition of Fe1-xSnx (x≤0.5).The atomic alloying the formation and microstructure, especially the coordination environments, of the resultant alloys have been studied by X-ray diffraction, 57Fe and 119Sn Mossbauer Spectroscopy and diffrrential scanning calorimetry. The Fe and Sn coordination environments and the composition dependence of the hyperfine parameters on the Fe and Sn content have been fully discussed with respect to the solid dissolution alloying, grain refinement, and distortion caused or induced by mechanical alloying.

关键词: mechanical alloying , null , null

MICROSTRUCTURE STUDY ON 16.5mol% CeO2-ZrO2 BY MEANS OF TRANSMISSION ELECTRON MICROSCOPE

L-F. Li , Z. Zhang , and Y Y Li(Cryogenic Laboratory Chinese Academy of Sciences , Beijing 100080 , China)(Institute of Metal Research , Chinese Academy of Sciences , Shenyang 110015 , China)

金属学报(英文版)

The microstructure of a fine-grained 16.5mol% CeO2 stabilized tetragonal zirconia polycrystal (Ce-TZP has been investigated by TEM and it is shown that the mi-crostructures of samples fractured at 298, 77 and 4.2 K change significantly. At 298K there is no stress-induced martensite but a few anti-phase boundaries (APBs) in tetragonal (t) parent phase. With a decrease in temperature, monoclinic (m) product or mariensite within retained t-phase appears. The morphologies are characterized as lenticular and block-like at 77 K and as lenticular and butterfly-like at 4.2 K. The relationship between microstructure and mechanical properties is also discassed in this paper.

关键词: microstructure , null , null

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

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

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

Luoyang Institute of Refractories Research Ministry of Metallurgical Industry

ZHONG Xiangchong Luoyang Institute of Refractories Research , Luoyang , China.

材料科学技术（英文）

关键词:

Guangzhou Institute of Energy Conversion,The Chinese Academy of Sciences,Guangzhou 510070,China

B.W. Wang , H. Shen

金属学报(英文版)

Ni-Cr System solar selective thin solid films were prepared by d.c. magnetron reactivesputtering under the atmosphere of O2 and N2. Ni-Cr alloy was chosen as targetmaterial and copper sheets as substrate. Using SEM, Spectrophotometer and Talystepto analyze the relations between the selective characteristic and the structure, theformation and the thickness of the thin films. The aim is to obtain good solar selectivethin films with high absorptance and low emittance, which is applied to flat plate solarheat collectors.

关键词: solar selective thin film , null , null , null

Development of Cast Superalloys for Gas Turbines in China

CHEN Rongzhang CHEN Wanhua Institute of Aeronautic Materials , Beijing 100095 , China.

材料科学技术（英文）

As in other countries,significant achievements in the research of cast superalloys for many years have also been obtained in China.These results are important contribu- tion to the development of aero and land-based gas tur- bine engines.

关键词: cast superalloy , null