材料期刊网

Characterization of ThMn_(12)-structure Stability

By GENG Mingming MA Ruzhang XU Zuxiong WANG Genmiao ** Dept.of Material Physics , University of Science and Technology Beijing , Beijing , 100083 , China*** Structure and Element Analysis Lab. , University of Science and Technology of China , Hefei , 230026 , China+ To w

材料科学技术（英）

A series of YTi(Fe_(1-x)_(11)alloy with x=0.00,0.01,0.03,0.04,0.05,0.07 and 0.10 has been investigated by measurement of the structural properties and ~(57)Fe M(?)ssbauer experiments.The pure ThMn_(12)-structure phase exists at x≤0.03 and is absent at x>0.03.The reasons for lower satura- tion magnetization and lower energy product of the ThMn_(12)-structure compounds were given.The crystal structure relations between R_2Fe_(17)-structure and ThMn_(12)-structure were discussed.Comparing with the R_2Fe_(17)and R_2Fe_(14)B compounds,the ThMn_(12)-structure RFe_(12-x)M_x compounds have the same magnetic moment of Fe at x=0.The potential for increasing the saturation magnetization of ThMn_(12)-structure compounds may be enhanced by the addition of stabilization elements.

关键词: ThMn_(12)-structure stability , null , null

FINITE ELEMENT ANALYSIS TO THE FATIGUE STRENGTH OF SYNCHRONOUS BELT TEETH

T.L Guo , Y. Qi and Y.H. Cheng Scientific Research Department , Shenyang University , Shenyang 110044 , China

金属学报(英文版)

By means of finite element analysis methods calculated the stress, strainand displacement of the belt teeth and analysisied the factors such as load distribution,specific property coefficient of material and temperature variation, which influence the fatigue strength of the belt teeth..

关键词: finite element analysis , null , null

Finite Element Analysis of Axial Feed Bar Rolling

C.G. Xu , G.H. Liu

金属学报(英文版)

A flexible technique of hot working of bars by axial feed rolling was introduced . The process deformation, strain field, stress field, and temperature field of the parts are analyzed by finite element method (FEM)-simulation software DEFORM-3D. The material flow rule and tool load have been investigated.

关键词: axial feed bar rolling , null , null

PHASE EXTENSION AND STRUCTURE ANALYSIS BY THE MAXIMUM ENTROPY METHOD

G.B.Hu and Q.B.Yang (Department of Physics , Xiangtan University , Xiangtan 411105 , China)(Beijing Laboratory of Electron Microscopy , Center for Condensed Matter Physics , The Chinese Academy of Sciences , P. O. Box 2724 , Beijing 100080 , China)

金属学报(英文版)

Excellent results are obtained in structure analysis with jew phases of structure factors by the maximum-entropy method (MEM) for CaGaN PbCO3 and ReBe22 single crystals. The computation time and memory space are minimized by symmetry operations so that structure analysis by the MEM can be carried out with a personal computer.

关键词: maximum entropy method , null , null , null

Element Analysis of Instrumented Sharp Indentations into Pressure-sensitive Materials

Minh-Quy LE , Seock-Sam KIM

材料科学技术（英）

Finite element analysis was carried out to investigate the conical indentation response of elastic-plastic solids within the framework of the hydrostatic pressure dependence and the power law strain hardening. A large number of 40 different combinations of elasto-plastic properties with n ranging from 0 to 0.5 and σy/E ranging from 0.0014 to 0.03 were used in the computations. The loading curvature C and the average contact pressure pave were considered within the concept of representative strains and the dimensional analysis. Dimensionless functions associated with these two parameters were formulated for each studied value of the pressure sensitivity. The results for pressure sensitive materials lie between those for Von Mises materials and the elastic model.

关键词: Finite element analysis , null , null , null

Finite element analysis of stresses associated with transformations in magnesia partially stabilized zirconia

Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing

Anisotropy finite element analysis was performed to study stresses associated with the tetragonal precipitates and the tetragonal to monoclinic transformation in MgO partially stabilized zirconia. Stresses were assumed to be caused by the lattice misfits between the product phase and the parent phase. In the finite element calculations, the tetragonal and monoclinic precipitates were assumed to be lenticular in shape, and the anisotropic elastic constants of the cubic, tetragonal and monoclinic phases were considered. The purpose of this paper is to obtain some knowledge about how stresses respond when the microstructure is changed, and how stress fields affect microstructure development. The finite element results show that increasing a,ln, and decreasing c(t)/a(c) can create a favorable stress field to reduce the growth rate of tetragonal precipitates during the heat treatment. Stresses associated with the single tetragonal precipitate in an infinite cubic matrix are distinctly larger than stresses associated with the homogeneously distributed tetragonal precipitates. The twin orientations within the monoclinic particle greatly affect stresses associated with the tetragonal to monoclinic transformation. (C) 1999 Elsevier Science S.A. All rights reserved.

关键词: finite element analysis;transformations;magnesia partially stabilized;zirconia;coherent ti11ni14 precipitate;computer-simulation;martensitic-transformation;tetragonal zirconia;microstructural;development;elastic-constants;zro2;ceramics;growth;alloys

CLAS+FROST: new generation of photoproduction experiments at Jefferson Lab.

中国物理C

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Finite element analysis of gamma ' directional coarsening in Ni-based superalloys

Zeitschrift Fur Metallkunde

A three-dimensional anisotropic finite element analysis was performed to calculate the hydrostatic pressure, elastic strain energy density and von Mises stress associated with periodically arranged cubic gamma' precipitates in the gamma matrix of Ni-based superalloys. Inhomogeneous and anisotropic elastic media are considered, the effects of different lattice misfit and external loads are investigated. The results show that the asymmetry of the hydrostatic pressure, the strain energy density and von Mises stress could be used to predict the gamma' directional coarsening. The contribution of hydrostatic pressure to the total driving force is smaller than that of von Mises stress and the elastic strain energy. The reason was briefly discussed.

关键词: finite element analysis;Ni-based superalloys;rafting;coarsening;single-crystals;microstructural evolution;computer-simulation;internal-stresses;creep-deformation;uniaxial stress;strain-energy;driving-force;shape changes;mechanism

Finite element analysis of microimprinting of bulk metallic glasses in supercooled liquid regime

Journal of Materials Science

A finite element analysis (FEA) model to analyze imprint of a bulk metallic glass (BMG) in the temperature range near the glass transition temperature (T-g) has been developed. The material model includes both Newtonian and non-Newtonian flow behavior. The results reveal that the topology of the imprinted surface depends strongly on temperatures, but only mildly on surface feature scale. As a result of the flow characteristics of BMG in the temperature range above T-g, the lubrication condition has only a slight effect on BMG imprinting.

关键词: superplasticity;alloys;flow

Analysis of Strip Temperature in Hot Rolling Process by Finite Element Method

MEI Rui-bin , LI Chang-sheng

钢铁研究学报(英文版)

The program was developed by finite element method to calculate the temperature distribution in hot strip rolling. The heat transfer coefficient of air cooling, water cooling and thermal resistance between work roll and strip were analyzed. A new heat generate rate model was proposed according to the influence of source current density, work frequency, air gap and distance to edge on induction heating by finite element method (FEM). The heat generate rate was considered into the thermal analysis to predict the temperature distribution in the induction heating. The influence of induction heating on the strip temperature was investigated with different strip thicknesses. The temperature difference became more and more obvious with the increase of thickness. The strip could be heated quickly by the induction heating both in surface and center because of the thermal conductivity and skin effect. The heat loss of radiation has important influence on the surface temperature. The surface temperature could be heated quickly with high frequency when the strip is thicker.

关键词: Temperature distribution;Finite element method;Induction heating;Skin depth;Hot rolling