材料期刊网

~(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

Department of Metallurgy and Materials Engineering of Chongqing University

YAN Guangting Chongqing University , Sichuan , China.

材料科学技术（英文）

关键词:

Service Performance of Engineering Materials

Andrej Atrens

材料科学技术（英文）

Corrosion research by Atrens and co-workers has made significant contributions to the understanding of the service performance of engineering materials. This includes: (1) elucidated corrosion mechanisms of Mg alloys, stainless steels and Cu alloys, (2) developed an improved understanding of passivity in stainless steels and binary alloys such as Fe-Cr, Ni-Cr, Co-Cr, Fe-Ti, and Fe-Si, (3) developed an improved understanding of the melt spinning of Cu alloys, and (4) elucidated mechanisms of environment assisted fracture (EAF) of steels and Zr alloys. This paper summarises contributions in the following: (1) intergranular stress corrosion cracking of pipeline steels, (2) atmospheric corrosion and patination of Cu, (3) corrosion of Mg alloys, and (4) transgranular stress corrosion cracking of rock bolts.

关键词: Stress corrosion cracking , null , null

Stereology in Materials Science

LIU Guoquan Department of Materials Science and Engineering , University of Science and Technology Beijing , 100083 , China.

材料科学技术（英文）

Quantitative analysis of populations having a geometric structure,which has developed into a special scientific subject called microstructology or stereology,is of great importance to the characterization and evaluation of microstructures and their evolution in various processes.This paper, besides a brief discussion on those topics such as the recent developments of computer assisted image analysis,mathematical morphology,and fractal analysis,will mainly focus on the scope,fundamen- tals,present status,and perspectives of classical stereology.Several case examples of its application to materials science will also be given.

关键词: stereology , null , null , null

Biomimicry of bamboo bast fiber with engineering composite materials

Materials Science & Engineering C-Biomimetic Materials Sensors and Systems

Bamboo, one of the strongest natural structural composite materials, has many distinguishing features. It has been found that its reinforcement unit, hollow, multilayered and spirally-wound bast fiber, plays an extremely important role in its mechanical behavior. In the present work, on the basis of the study on bamboo bast fiber and wood tracheid, a biomimetic model of the reinforcing element, composed of two layers of helically wound fiber, was suggested. To detect the structural characteristics of such a microstructure, four types of macro fiber specimens made of engineering composites were employed: axially aligned solid and hollow cylinders, and single- and double-helical hollow cylinders. These specimens were subjected to several possible loadings, and the experimental results reveal that only the double-helical structural unit possesses the optimum comprehensive mechanical properties. An interlaminar transition zone model imitating bamboo bast fiber was proposed and was verified by engineering composite materials. In our work, the transition zone can increase the interlaminar shear strength of the composite materials by about 15%. These biomimetic structural models can be applied in the design and manufacture of engineering composite materials.

关键词: bamboo;bast fiber;biomimetics;engineering composites

Strengthening Materials by Engineering Coherent Internal Boundaries at the Nanoscale

Science

Strengthening materials traditionally involves the controlled creation of internal defects and boundaries so as to obstruct dislocation motion. Such strategies invariably compromise ductility, the ability of the material to deform, stretch, or change shape permanently without breaking. Here, we outline an approach to optimize strength and ductility by identifying three essential structural characteristics for boundaries: coherency with surrounding matrix, thermal and mechanical stability, and smallest feature size finer than 100 nanometers. We assess current understanding of strengthening and propose a methodology for engineering coherent, nanoscale internal boundaries, specifically those involving nanoscale twin boundaries. Additionally, we discuss perspectives on strengthening and preserving ductility, along with potential applications for improving failure tolerance, electrical conductivity, and resistance to electromigration.

关键词: strain-rate sensitivity;stacking-fault energy;nano-scale twins;cu-al;alloys;nanocrystalline metals;mechanical-properties;activation;volume;copper;deformation;behavior

SOFC阴极材料(La_(0.85)Sr_(0.15))_y(Mn_(1-z)Cr_z)O_3的物理性能和化学稳定性

杨威 , 隋智通

材料研究学报

采用烧结法制备阴极材料(La0.85Sr0.15)y(Mn1z-Crz)O3(y=0.85;1;z=0.1,0.2).研究了多孔锰酸镧与致密ZrO2(8mol%Y2O3)界面的成分变化和显微形貌(La0.85Sr0.15)(Mn0.9Cr0.1)O3呈现高电子电导率、良好的热膨胀系数匹配和化学稳定性而(La0.85Sr0.15)MnO3未起到阻止界面退化的作用在1300～1500℃范围内Mn、La、Zr和Sr发生扩散,其中Mn的扩散明显

关键词: SOFC , lathanum manganite. chemical stability , thermal expansion , conductivity , null

Application of Fractal Theory in the Synthesis of Nano-sized 3Y-TZP Superplastic Ceramic Materials

Guofeng WANG , Kaifeng ZHANG , Dezhong WU

材料科学技术（英文）

Nano-sized 3Y-TZP powders were Synthesized by two methods. A fractal software was developed. A new and convenient method for characterizing the quality of Synthetic process by using fractal theory was obtained.

关键词:

Mean-field theory on mixed ferro-ferrimagnetic compounds with (A(a)B(b)C(c))(y)D

Physics Letters A

The magnetic properties of the mixed ferro-ferrimagnetic compounds with (A(a)B(b)C(c))(y)D, in which A, B, C and D are four different magnetic ions and form four different sublattices, are studied by using the Ising model. And the Ising model was dealt with standard mean-field approximation. The regions of concentration in which two compensation points or one compensation point exit are given in c-a, b-c and a-b planes. The phase diagrams of the transition temperature T-c and compensation temperature T-comp are obtained. The temperature dependences of the magnetization are also investigated. Some of the result can be used to explain the experimental work of the molecule-based ferro-ferrimagnet ((NiaMnbFecII)-Mn-II-Fe-II)(1.5) [Cr-III (CN)6] - zH(2)O. (C) 2003 Elsevier B.V. All rights reserved.

关键词: mixed ferro-ferrimagnet;Ising model;four sublattices;phase diagram;transition temperature;compensation temperature;magnetic-properties;prussian blue;alloy

直流磁场对Mg-Y-C u-Z r合金结晶取向和性能的影响?

黄曼青 , 周全 , 刘峰 , 黄金角

材料导报 doi:10.11896/j.issn.1005-023X.2016.22.010

研究了0~1.4 T的直流磁场对陶瓷型铸造 Mg-Y-Cu-Zr 合金结晶取向和力学性能的影响。结果表明直流磁场对合金的初生相没有明显影响，但磁场强度大于1.12 T时，合金第二相的分布变得不连续。当磁场强度小于0.84 T时，α-Mg在(002)面的衍射峰逐渐增强，但变化不明显；当磁场强度大于0.84 T 时，α-Mg 基体在(002)、(101)面的衍射峰强度明显减弱，而在(100)晶面衍射峰强度有所增强。磁场处理后，合金的综合力学性能得到了改善；当磁场强度为1.4 T 时，其抗拉强度和伸长率最高，分别为237 MPa 和8.5%，较无磁场处理时分别提高了38.6%和33.4%。

关键词: 直流磁场 , Mg-Y-Cu-Zr合金 , 结晶取向 , 力学性能