材料期刊网

Computer Model of Phase Transformation From HotDeformed Austenite in Niobium Microalloyed Steels

XU Yunbo , YU Yongmei , LIU Xianghua , WANG Guodong

钢铁研究学报(英文版)

Based on thermodynamics and kinetics, a new mathematical model was developed to calculate the CCT diagrams and the transformation kinetics in low carbon niobium steels, in which the effect of deformation on the degree of supercooling was taken into account. The undercooling caused by deformation is the major reason for the increase of the starting transition temperature during continuous cooling. The critical cooling rate of bainite formation is within 2-5 ℃/s for the studied niobium steels and deformation is suitable for the occurrence of pearlite. The ferrite volume fraction increases with the increase of the austenite boundary area, and decreases with the increase of the cooling rate. The calculated CCT diagrams and the volume fraction of each phase are in good agreement with the measurements.

关键词: low carbon niobium steel;thermodynamics;supercooling degree;continuous cooling transformation;computer model

Prediction of Rolling Load, Recrystallization Kinetics, and Microstructure During Hot Strip Rolling

XU Yunbo , YU Yongmei , LIU Xianghua , WANG Guodong

钢铁研究学报(英文版)

The recrystallization kinetics and grain size models were developed for the CMn and niobiumcontaining steels to describe the metallurgical phenomenon such as softening, grain growth, and strain accumulation. Based on the recrystallization kinetics equations, the mean flow stress and the rolling load of each pass were predicted and the optimum rolling schedule was proposed for hot strip rolling. The austenite grain refinement is associated with the addition of niobium, the decrease of starting temperature of finish rolling, and the reduction of finished thickness. The mean flow stress curve with a continuous rising characteristic can be usually observed in the finish rolling of niobiumcontaining steel, which is formed as a result of the heavy incomplete softening and strain accumulation. The predicted rolling loads are in good agreement with the measured ones.

关键词: hot strip rolling;recrystallization;mean flow stress;strain accumulation;grain size

Professor XU Zhong-yu and his research activities

新型炭材料

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含MEI结构单元的介孔Ti-HMS-1的合成、表征及催化氧化性能

马乾志 , 郭杨龙 , 王艳芹 , 郭耘 , 张志刚 , 卢冠忠

无机材料学报 doi:10.3321/j.issn:1000-324x.2007.05.033

采用TS-1前驱体作硅源和钛源,以十二胺为模板剂,在中性和室温条件下合成了介孔含钛分子筛Ti-HMS-1.采用XRD、TEM、低温N2吸附、FT-IR和UV-Vis等方法对合成的分子筛进行了表征;以苯乙烯的催化氧化反应为模型反应,考察了合成的Ti-HMS-1的催化氧化性能.结果表明,Ti-HMS-1具有"worm-like"介孔结构,但长程有序度较低,孔壁部分含有MFI的次级结构单元,在373K沸水中水煮50h后,Ti-HMS-1仍能较好地保持原有的介孔结构,表明Ti-HMS-1具有较高的水热稳定性.进入分子筛骨架的钛原子为催化剂的活性中心,对于苯乙烯氧化反应,具有较高的催化活性,对产物的选择性与Ti-HMS接近.

关键词: Ti-HMS-1分子筛 , 合成 , 表征 , 苯乙烯氧化

Preface to Special Issue on Photocatalysis for celebrating the 20th anniversary of Professor Jimmy C. Yu’s return to Hong Kong and leading photocatalytic research there

催化学报 doi:10.1016/S1872-2067(15)61006-3

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Molecular dynamics study of atomic transport properties in rapidly cooling liquid copper

Journal of Chemical Physics

Based on Mei's embedded atom model [Mei , Phys. Rev. B 43, 4653 (1991)] molecular dynamics simulations have been performed to investigate the rapidly cooling processes of Cu. The atomic transport property, namely the self-diffusion coefficient, is computed in the liquid state, and the results near the melting point of Cu are in good agreement with experimental data and other computational values. The atom diffusion movements during the long period of relaxation have been also studied around the solidification temperature T-c. To describe the complex microstructural evolutions during the rapidly cooling processes and the long relaxation processes, the pair correlation function and the pair analysis technique are used. It is demonstrated that the crystallization of amorphous Cu is caused by the atomic diffusion. (C) 2004 American Institute of Physics.

关键词: transition-metals;computer-simulation;supercooled-liquid;model;fcc;potentials;diffusion

Improved Nonlinear Equation Method for Numerical Prediction of Jominy EndQuench Curves

SONG Yuepeng , LIU Guoquan , LIU Shengxin , LIU Jiantao , FENG Chengming

钢铁研究学报(英文版)

Without considering the effects of alloying interaction on the Jominy endquench curves, the prediction results obtained by YU Baihai′s nonlinear equation method for multialloying steels were different from those experimental ones reported in literature. Some alloying elements have marked influence on Jominy endquench curves of steels. An improved mathematical model for simulating the Jominy endquench curves is proposed by introducing a parameter named alloying interactions equivalent (Le). With the improved model, the Jominy endquench curves of steels so obtained agree very well with the experimental ones.

关键词: Jominy endquench curve;nonlinear equation method;alloying interaction parameter;computer simulation

1998 COMPREHENSIVE TABLE OF CONTENTS

中国腐蚀与防护学报

N。1Atmospheric Corrosivlty for Steels………………………………………………… .LIANG Caideng HO[I i。-tat（6）Caustic Stress Corrosion Cr。king of Alloy 800 Part 2.The Effect of Thiosul执e……………………………………… KONG De-sheng YANG Wu ZHAO Guo-zheng HUANG De.ltL。ZHANG Yu。。he CHEN She。g-bac（13）SERS slid E16CttOCh6iniC81 Stlldy Of Illhibit1Oli M6ch＆tllsth Of ThlollY68 Oil ITOll ID H....

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三维晶粒长大速率方程的大尺度Potts模型Monte Carlo仿真验证

王浩 , 刘国权 , 秦湘阁

金属学报

采用Potts模型Monte Carlo方法对3种现存的三维个体晶粒长大速率拓扑依赖性 方程进行了仿真验证. 结果表明, Rivier速率方程认为晶粒 体积变化率dVf/dt与晶粒面数f成线性关系, 与仿真 结果明显不符, 不适用于描述三维晶粒长大过程的动力 学. 当晶粒面数f≥8时, Yu-Liu速率方程和 MacPherson-Srolovitz速率方程均与仿真结果很好吻合, 表明这两者均可以用来定量描述三维晶粒长大过程的动力学；当 f＜8时, 这两个方程均与仿真结果有显著差异.

关键词: 三维晶粒长大 , topology-dependent grain growth rate equation

三维晶粒长大速率方程的大尺度Potts模型Monte Carlo仿真验证

王浩 , 刘国权 , 秦湘阁

金属学报 doi:10.3321/j.issn:0412-1961.2008.01.003

采用Potts模型Monte Carlo方法对3种现存的三维个体晶粒长大速率拓扑依赖性方程进行了仿真验证.结果表明,Rivier速率方程认为晶粒体积变化率dVf/dt与晶粒面数,成线性关系,与仿真结果明显不符,不适用于描述三维晶粒长大过程的动力学.当晶粒面数f≥8时,Yu-Liu速率方程和MacPherson-Srolovitz速率方程均与仿真结果很好吻合,表明这两者均可以用来定量描述三维晶粒长大过程的动力学;当f<8时,这两个方程均与仿真结果有显著差异.

关键词: 三维晶粒长大,拓扑依赖性长大速率方程,Potts模型,Monte Carlo仿真