材料期刊网

A CHALLENGE FOR BIAXIAL AND TRIAXIAL CREEP TESTING

M. Sakane (Department of Mechanical Engineering , Faculty of Science and Engineering , Ritsumeikan University , 1-1-1Nojihigashi Kusatsu-shi Shiga , 525-8577 , Japan)S. Mukai (Power Reactor and Nuclear Fuel Development Corporation , 4002 Narita-cho Oarai-cho Ibaragibun Ibaragi , 311-13 , Japan)

金属学报(英文版)

This paper describes new methods for biaxial and triaxial creep testing. Biaxial tension and triaxial tension creep testers were developed. The performance of the machines was described and some test results were discussed. Stress biaxiality had almost no effect on the creep deformation and Mises potential was suitable for describing the creep deformation under biaxial and triaxial stress states. Stress biaxiality had a small influence on prolonging creep rupture time under the constant Mises stress condition.A new triaxial tension creep testing method was discussed together with the shape of the triaxial creep specimen.

关键词: creep , null , null , null , null

Frontiers of Surface and Interface Science and Engineering 2004 (FSISE 2004)Conference

金属学报(英文版)

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

Crystal facet engineering of semiconductor photocatalysts: motivations, advances and unique properties

Chemical Communications

Crystal facet engineering of semiconductors has become an important strategy for fine-tuning the physicochemical properties and thus optimizing the reactivity and selectivity of photocatalysts. In this review, we present the basic strategies for crystal facet engineering of photocatalysts and describe the recent advances in synthesizing faceted photocatalysts, in particular TiO(2) crystals. The unique properties of faceted photocatalysts are discussed in relation to anisotropic corrosion, interaction dependence of adsorbates, photocatalytic selectivity, photo-reduction and oxidation sites, and photocatalytic reaction order. Ideas for future research on crystal facet engineering for improving the performance of photocatalysts are also proposed.

关键词: shape-controlled synthesis;exposed 001 facets;rutile tio2 nanorods;visible-light photocatalysis;solvent-solute interactions;anatase;titanium(iv) oxide;low-temperature synthesis;ordered solid-phases;platinum nanocrystals;hydrogen-production

Study on compression behavior of porous magnesium used as bone tissue engineering scaffolds

Biomedical Materials

In this work, porous magnesium (Mg) with a three-dimensional open-cellular structure, potentially employed as bone tissue engineering scaffolds, was fabricated by the mechanical perforation method. The influences of porosity, pore size and pore arrangement on compressive behavior and the anisotropy of new porous Mg were analyzed theoretically using orthogonal arrays and the finite element method (FEM). The results showed that the parameters of porosity, pore size and pore arrangement had different effects on the compressive properties. The compressive strength could be improved by optimizing these parameters. The anisotropy of porous Mg was also verified in this study. The theoretical results showed good agreement with the experimental ones before the strain reaches 0.038.

关键词: unidirectional solidification;pore-size;hydroxyapatite;replacement;cartilage;porosity;matrix

EFFECT OF THE CONTROLLED ROLLING CONTROLLED COOLING ON STRENGTH AND DUCTILITY OF THE BAINITE MICRO ALLOYED ENGINEERING STEEL

Z. Li , G. D. Wang , X. H. Liu and C. Y. Ma The State Key Lab. of Rolling Technology and Automation , Northeastern Univarsity , Shenyang 110006 China

金属学报(英文版)

The continuous cooling transformation of hot deformation austenite austenite of test steel and the effect of different processing schedules of controlled rolling and controlled cooling on the strength and ductility have been studied. The theory and the experiment base are presented for controlled rolling and controlled cooling of the SBL micro alloyed engineering steel.

关键词: micro alloyed engineering steel , null , null , null

Improvement of Intergranular Stress Corrosion Crack Susceptibility of Austenite Stainless Steel through Grain Boundary Engineering

Weizhong JIN , Sen YANG , Hiroyuki KOKAWA , Zhanjie WANG , Yutaka S.Sato

材料科学技术（英文）

Intergranular stress corrosion crack susceptibility of austenite stainless steel was evaluated through threepoint bending test conducted in high temperature water. The experimental results showed that the frequent and efficient introduction of low energy coincidence site lattice boundaries through grain boundary engineering resulted in an apparent improvement of the intergranular stress corrosion crack resistance of austenite stainless steel.

关键词: Intergranular stress corrosion cracking , null , null