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An Application of the Modified Shear Lag Model to Study the Influence of Thermal Residual Stresses on the Stiffness and Yield Strength of Short Fiber Reinforced Metal Matrix Composites

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Journal of materials science & Technology 1999年第3期15卷 213-221页

作者： Zhonghao JIANG and Jianshe LIAN(Dept. of materials science and engineering, Jilin University of Technology, Changchun 130025, china)Shangli DONG and Dezhuang YANG(school of materials science and engineering, Harbin Institute of Technology, Harbin 150001, Dept. of materials science and engineering Jilin University of Technology Changchun 130025 China school of materials science and engineering Harbin Institute of Technology Harbin 150001 China

The modified shear lag model proposed recently was applied to calculate thermal residual stresses and subsequent stress distributions under tensile and compressive loadings. The expressions for the elastic moduli and the yield strengths under tensile and compressive loadings were derived which take account of thermal residual stresses. The asymmetries in the elastic modulus and the yield strength were interpreted using the derived expressions and the obtained results of the stress calculations. The model predictions have exhibited good agreements with the experimental results and also with the other theoretical predictions

关键词： ab Figure An Application of the Modified Shear Lag Model to Study the Influence of Thermal Residual Stresses on the Stiffness and Yield Strength of Short Fiber Reinforced Metal Matrix Composites

INFLUENCES OF ACID POST-TREATMENT ON THE MORPHOLOGY OF SOAP-FREE P(MMA-EA-MAA)PARTICLES PREPARED BY SEEDED EMULSION POLYMERIZATION

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Chinese Journal of Polymer science 2005年第5期23卷 479-485页

作者： Kai Kang Cheng-you Kan Yi Du De-shan Liu Department of Chemical engineering,school of materials science and engineering,Tsinghua University,Beijing 100084,china Tsinghua Univ Dept Chem Engn Sch Mat Sci & Engn Beijing 100084 Peoples R China

Soap-free poly（methyl methacrylate-ethyl acrylate-methacrylic acid） latex particles with narrow size distribution were synthesized by seeded emulsion polymerization, and the porous particles were created by a stepwise alkali/acid treatment method. Effects of acid treatment conditions on the particle morphology were investigated. Results show that one to three pores were formed inside most of particles after post-treatment. At pH 7.0, when the treatment temperature was lower than 70℃, the size of particles and the volume of pores remained almost unchanged, and these two values increased significantly when the temperature was higher than 70℃. Both the particle size and the pore volume decreased with the increase of initial pH value and treatment time in the acid treatment. As the pH was below 4.0 and the treatment time was longer than 180 min, the particles shrunk in size.

关键词： Soap-free emulsion polymerization Particle morphology Porous structure Acid treatment Methyl methacrylate based copolymer.

Microstructure and wear resistance of PTA clad Cr7C3/γ-Fe ceramal composite coating

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Progress in Natural science:materials International 2006年第8期16卷 874-878页

作者： LIU Junbo, WANG Limei and HUANG Jihua (Weifang University, Weifang 261061, china school of materials science and engineering, University of science and Technology, Beijing 100083, china) Weifang University Weifang 261061 China school of materials science and engineering University of Science and Technology Beijing 100083 China

A wear resistant Cr7C3/γ-Fe ceramal composite coating was fabricated on substrate of the hardening and tempering C degree steel by PTA (plasma transferred arc) cladding with (wt%) Fe-25Cr-7C elemental powder blends. Microstructure of the coating was characterized by OM, SEM, XRD and EDS. Wear resistance of the coating was tested under dry sliding wear condition at room temperature. The results indicate that the PTA clad ceramal composite coating has a rapidly solidified fine microstructure consisting of Cr7C3 primary particles uniformly distributed in theγ-Fe matrix and is metallurgically bonded to the C degree steel substrate. The PTA clad Cr7C3/γ-Fe ceramal composite coating has high hardness and excellent wear resistance under dry sliding wear test conditions. The excellent wear resistance of the Cr7C3/γ-Fe ceramal composite coating is attributed to the coating's high hardness, strong covalent atomic bonding and refined microstructure.

关键词： PTA clad Cr7C3/γ-Fe composite coating microstructure wear resistance.

Study on soil solidification based on microbiological precipitation of CaCO_3

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science china(Technological sciences) 2010年第9期53卷 2372-2377页

作者： LU WangJie,QIAN ChunXiang & WANG RuiXing school of materials science & engineering,Jiangsu Key Laboratory for Construction materials,Southeast University,Nanjing 210089,china 1. school of materials science & engineering Jiangsu Key Laboratory for Construction Materials Southeast University Nanjing 210089 China

The soil solidifying technology started booming from the 1940s and formed an integrated *** paper aimed to study the effect and mechanism of soil solidification by *** specimens treated by different methods were *** the compressive strengths of these specimens on day 7 were tested and the situ bacteria culturing technique in soil was *** the mechanism of soil solidification by microorganisms was explored according to the decomposition rate of substrate,pH value and the SEM and XRD *** results showed that the soil could be solidified by filling enhancement and precipitation of *** compressive strength increased with bacteria A but decreased with substrate B,and soil specimen got a higher strength with bacteria situ *** suitable pH value for bacteria A was 8–9,and the delay of lime addition could make substrate decomposition more completely,lower the influence by the existence of substrate,and improve the *** XRD and SEM images,precipitation of CaCO3 could be speculated.

关键词： soil solidification bacteria compressive strength situ cultured decomposition rate precipitation

Synthesis and characterization of ZnO nanostructures prepared by a thermal evaporation process

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Rare Metals 2007年第S1期26卷 153-156页

作者： CAI Wei,and LIU Wencheng school of materials science and engineering,Harbin Institute of Technology,Harbin 150001,china Harbin Inst Technol Sch Mat Sci & Engn Harbin 150001 Peoples R China

A series of ZnO nanostructures such as nanowires,nanobelts,nanocombs and mesoporous nanoballs were fabricated by a simple carbon reduction method without *** morphologies and microstructures of all samples were characterized by X-ray diffraction,scanning electron microscopy,transmission electron microscopy,and energy dispersive X-ray *** results indicate that different deposition temperatures have great impact on different shapes of ZnO *** growth mechanisms of these ZnO nanostructrues suggest that,by controlling the experiment parameters,different morphological configurations nanostructures can be fabricated.

关键词： ZnO nanostructures thermal evaporation nanowires vapor deposition

Two-way Shape Memory Effect in a Ti-Ni-Nb Shape Memory Alloy with Wide Hysteresis

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Journal of materials science & Technology 2001年第1期17卷 13-14页

作者： Liming WANG Xianglong MENG Wei CAI and Liancheng ZHAO school of materials science and engineering, Harbin institute of Technology, Harbin 150001, china Harbin Inst Technol Sch Mat Sci & Engn Harbin 150001 Peoples R China

A two-way shape memory effect (TWSM E) in the Ti46.3Ni44.7Nb9 alloy has been systematically investigated by means of bending test and transmission electron microscopy (TEM ) observations. Based on the analysis of the ... 详细信息

关键词： Ti Ni Two-way Shape Memory Effect in a Ti-Ni-Nb Shape Memory Alloy with Wide Hysteresis Wide

Microstructure and Mechanical Properties of Si_3N_4 Composites Containing SiC Platelet

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Journal of materials science & Technology 1998年第2期14卷 151-155页

作者： Tao WEI Yu ZHOU Tingquan LEI and Yujin WANG (school of materials science and engineering, Harbin Institute of Technology, Harbin 150001, china) school of materials science and engineering Harbin Institute of Technology Harbin 150001 China

Hoppressed Si3N4/SiC platelet composites had been investigated with respect to their microstructure and mechanical properties. The results indicate that Vickers hardness, elastic modulus and fracture toughness of the composites were increased by the addition of SiC platelet until the content up to 20 vol pct. A slight decrease in flexural Strength was measured at room temperature with increasing SiC platelet content. The high temperature flexural strength tests at 1150, 12.0, and 1350℃ were conducted. It was found that the flexural strength at elevated temperature was degraded with the rising temperature, and the downward trend of flexural strength for the composite containing 10 vol. pct SiC platelet was less. The results indicate that SiC platelet had a positive influence on the high temperature strength. Effects of SiC platelet reinforcement were presented

关键词： SiC Microstructure and Mechanical Properties of Si3N4 Composites Containing SiC Platelet MPa

Microstructure and mechanical properties of extruded AZ31 magnesium alloy sheet

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Rare Metals 2007年第S1期26卷 226-230页

作者： WANG Xin,and FENG Jicai school of materials science and engineering,Harbin Institute of Technology,Harbin 150001,china Harbin Inst Technol Sch Mat Sci & Engn Harbin 150001 Peoples R China

The effects of billet temperature on the maximum punch load,microstructure and mechanical properties of the extrusion of AZ31 cast magnesium alloy were *** is found that with the temperature decreasing,the microstructure of extruded sheets is more homogeneous and the grains become *** grain refinement does little effect on the strength of the material but significantly affects the *** the billet temperature is kept constant at room temperature,the elongation of the billets is up to 23%.The mechanical properties at extrusion direction(ED) and transverse direction(TD) were also *** differences of the properties between ED and TD are not obvious.

关键词： AZ31 magnesium alloy extrusion dynamic recrystallization

High Temperature Tensile Properties of 30 vol. pct ZrCp/W Composite

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Journal of materials science & Technology 2003年第2期19卷 167-170页

作者： Yujin WANG, Yu ZHOU, Guiming SONG and Tingquan LEI school of materials science and engineering, Harbin Institute of Technology, Harbin 150001, china Sch. of Mat. Sci. and Eng. Harbin Inst. of Technol. Harbin 150001 China

In order to improve the high temperature strength of tungsten, 30 vol. pct ZrC particles were added to the tungsten matrix to form a 30ZrCp/W composite. The tensile properties from 20C to 1880C of the composite were examined. It was shown that with increasing testing temperature, the nonlinearity of the stress strain curve of 30ZrCp/W composite becames obvious over 12.0C and the Young's modulus decreases and the elongation increases. The ultimate tensile strength increases at first and then decreases with increasing testing temperature. The maximum strength of 431 MPa was obtained at 1000C. The strengthening mechanism at high temperatures is the load transfer to ZrC particles and dislocation strengthening of the tungsten matrix with an effect of grain boundary strengthening.

关键词： ZrCp/W composite Tensile strength High temperature Strengthening mechanism Load transfer Dislocation strengthening