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Effect of Preparation Methods on Mechanical Properties of PVA/HA Composite Hydrogel

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Journal of Bionic engineering 2010年第3期7卷 235-243页

作者： Dekun Zhang~1, Junjie Duan~1, Dagang Wang~2. Shirong Ge~2.1. School of materials science and {2., china university of Mining and technology Xuzhou 2.1116, P. R. china 2. School of Mechanical and Electrical {2., china university of Mining and technology, Xuzhou 2.1116, P. R. china [a] School of materials science engineering China University of Mining technology Xuzhou 221116 P. R. China [b] School of Mechanical Electrical engineering China University of Mining technology Xuzhou 221116 P. R. China

Poly(vinyl alcohol) (PVA)/hydroxyapatite (HA) composite hydrogel specimens were prepared with 15% PVA and 1%,2., 3%, 4% and 5% HA by repeated freezing-thawing. The tests of static and dynamic mechanical properties were carried out todiscuss the influence of different contents of HA and freezing-thawing cycles on the mechanical properties of PVA/HA compositehydrogel. The results of static mechanical tests showed that the PVA/HA composite hydrogel with 3% HA and ninefreezing-thawing cycles had excellent stress relaxation properties, higher relaxation ratio, lower stress equilibrium value andpresented better properties of creep and recovery. The results of dynamic mechanical test showed that the PVA/HA compositehydrogel with nine freezing-thawing cycles had higher storage modulus and loss modulus, so was the PVA/HA compositehydrogel with 3% HA.

关键词： composite hydrogel HA contents freezing-thawing cycles static properties dynamic properties

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 2.1061, china School of {2. science and engineering, university of science and technology, Beijing 100083, china) Weifang university Weifang 261061 China School of materials science and {2. 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-2.Cr-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.

Texture Evaluation of α_2.Phase in Ti-2.Al-10Nb-3V-1Mo Alloy Sheet

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Journal of materials science & {2. 1996年第5期12卷 361-364页

作者： Weimin MAO Yongning YU Hong YANG and Bo SONG (Dept. of materials science and {2., university of science and technology Beijing, Beijing 100083, china) Dept. of materials science and {2. University of Science and Technology Beijing Beijing 100083 China

The texture evaluation of α2.phase in Ti-2.Al-10Nb-3V-1Mo sheet during rolling and annealing has been investigated by means of microstructure observation and ODF analysis. From the weak initial {1010} (12.0) and {000... 详细信息

The texture evaluation of α2 phase in Ti-25Al-10Nb-3V-1Mo sheet during rolling and annealing has been investigated by means of microstructure observation and ODF analysis. From the weak initial {1010} (1210) and {0001}(1210) textures a {1210}(1010) texture and a {0001}(uvtw)fibre texture are formed after cold rolling. The {0001} (1210) texture is also strengthened simultaneously. The activation process of slip systems is discussed concerning formation of the rolling texture. Because of the disappearance of {0001} (nvtw) fibre texture the primary recrystallization process should occur and the {1210}(1010) texture forms during annealing

关键词： Al Phase in Ti-2.Al-10Nb-3V-1Mo Alloy Sheet Ti Mo Texture Evaluation of

Slurry Preparation and Rolling of Semi-solid 60Si2.n Spring Steel

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Journal of materials science & {2. 2003年第6期19卷 613-616页

作者： Weimin MAO, Aimin ZHAO, Dong YUN, Leping ZHANG and Yonglin KANGSchool of materials science and {2., university of science & technology Beijing, Beijing 100083, china Sch. of Mat. Sci. and Eng. Univ. of Sci. and Technol. Beijing Beijing 100083 China

The nondendritic semi-solid slurry preparation of 60Si2.n spring steel has been studied in this paper. The experiments have shown that when stirred for 2.min on the test condition, the semi-solid slurry with 50%-60% fraction solid and spherical primary austenitic grains in the size of 100-300 μm can be obtained and is easy to be discharged from the bottom little hole of the stirring chamber. The nondendritic slurry of 60Si2.n spring steel can be rolled into given plate form successfully, but the solid phase and liquid phase is easy to be separated in rolling process so that the solid primary austenite is concentrated in the center and the liquid is near the edge of the rolled plate. The rupture strength and elongation of the plate rolled only once with semi-solid slurry are lower than that of the traditionally repeated hot-rolled plate of 60Si2.n spring steel.

关键词： 60Si2.n Semi-solid Electromagnetic stirring Rolling

Erosive Wear and Wear Mechanism of in situ TiC_P/Fe Composites

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Journal of materials science & {2. 2005年第5期21卷 719-723页

作者： Zhaojing LIU, Zhiliang NING , Fengzhen LI, Xiurong YAO and Shanzhi RENSchool of materials science and {2., Harbin university of science and technology, Harbin 150080, china School of materials science and {2. Harbin University of Science and Technology Harbin 150080 China

The base structure of in situ TiCp/Fe composites fabricated under industrial condition was changed by different heat treatments. Erosive wear tests were carried out and the results were compared with that of wear-resistant white cast iron. The results suggest that the wear resistance of the in situ TiCp/Fe composite is higher than that of wear-resistant white cast iron under the sand erosive wear condition. The wear mechanism of the wear-resistant white cast iron was a cycle process that base surface was worn and carbides were exposed, then carbides was broken and wear pits appeared. While the wear mechanism of in situ TiCp/Fe composite was a cycle process that base surface was worn and TiC grains were exposed and dropped. The wear resistance of in situ TiCp/Fe composite was lower than that of wear-resistant white cast iron under the slurry erosive wear condition. Under such circumstance, the material was not only undergone erosive wear but also electrochemistry erosion due to the contact with water in the medium. The wear behaviours can be a combination of two kinds of wear and the sand erosive wear is worse than slurry erosive wear.

关键词： In situ TiCp/Fe composite Erosive wear Wear mechanism

Development of Mathematical Model on Preparation of Functionally Graded Material by Co-sedimentation

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Journal of materials science & {2. 2001年第2期17卷 275-277页

作者： Zhongmin YANG, Lianmeng ZHANG and Qiang SHEN Institute of materials science and {2., Wuhan university of technology, Wuhan 430070, china Wuhan Univ Technol Inst Mat Sci & Engn Wuhan 430070 Peoples R China

From the process of sedimentation the mathematical relationships among deposition Volume and powder properties as well as sedimentation parameters were deduced. Based on the formula a mathematical model was set up and simulated through the computer. At last the validity of mathematical model was supported by the representative experiment on Ti-Mo system FGM prepared by co-sedimentation.

关键词： Co Mo Development of Mathematical Model on Preparation of Functionally Graded Material by Co-sedimentation

Reactive Diffusion Bonding of SiCp/Al Composites by Insert Powder Layers with Eutectic Composition

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Journal of materials science & {2. 2005年第5期21卷 779-781页

作者： Jihua HUANG Yueling DONG, Jiangang ZHANG, Yun WAN and Guoan ZHOUSchool of materials science and {2., university of science and technology Beijing, Beijing 100083, china School of materials science and {2. University of Science and Technology Beijing Beijing 100083 China

Mixed Al-Si and Al-Cu powders were investigated as insert layers to reactive diffusion bond SiCp/6063 metal matrix composite （MMC）. The results show that SiCp/6063 MMC joints bonded by the insert layers of the mixed Al-Si and Al-Cu powders have a dense joining layer of high quality. The mass transfer between the bonded materials and insert layers during bonding leads to the hypoeutectic microstructure of the joining layers bonded by both the mixed Al-Si and Al-Cu powders with eutectic composition. At fixed bonding time （temperature）, the shear strength of the joints by both insert layers of the mixed Al-Si and Al-Cu powders increases with increasing the bonding temperature （time）, but get maxima at bonding temperature 600℃ （time 90 min）.

关键词： Reactive diffusion bonding Insert powder layer SiCp/Al metal matrix composites

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 & {2. 1999年第3期15卷 213-221页

作者： Zhonghao JIANG and Jianshe LIAN(Dept. of materials science and {2., Jilin university of technology, Changchun 13002., china)Shangli DONG and Dezhuang YANG(School of materials science and {2., Harbin Institute of technology, Harbin 150001, Dept. of materials science and {2. Jilin University of Technology Changchun 130025 China School of materials science and {2. 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

Nonlinear Theory on Dynamic Controlling Interface Patterns DuringSolidification of a Dilute Binary Alloy

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International Journal of Minerals,Metallurgy and materials 1999年第4期13卷 253-258页

作者： Zidong Wang Hanqi Hu(Material science and engineering School, {2. of science and technology Beijing, Beijing 100083, china) Material science and engineering School University of Science and Technology Beijing Beijing 100083 China

In non-equilibrium nonlinear region, the nonlinear equations of time dependence of perturbation amplitude at the solid/liquidinterface during solidification of a dilute binary alloy are established on the base of assuming that there is local equilibrium at the solid/liquid interface and considering that curvature, temperature and composition at the solid/liquid interface which are related to the perturbation amplitude are nonlinear. As a result, patterns at the solid/liquid interface during solidification process, which is from nonsteadystate to steady state can be controlled by these nonlinear equations.

关键词： nonlinearity solidification, dilute binary alloy, dynamic control