材料期刊网，材料期刊，材料类期刊，材料期刊投稿

In order to meet the demand of prehardened steel for large section plastic mould and save energy, a nonquenched prehardened (NQP) steel is developed. The temperature field of a large block is researched by finite element method simulation and 9 test steels are designed in the laboratory. Their microstructures and hardness are investigated when they are air cooled and control cooled at cooling rate similar to the simulation. The result shows that the hardness uniformity through section is closely correlated to bainitic hardenability for the NQP steel, and the hardness of one test steel (027C195Mn104Cr045Mo01V) fluctuates between HRC 40 and 43 under both cooling conditions. The test steel has better machinability compared with C45 steel, and the NQP steel is produced successfully in the factory based on the laboratory results. Its microstructure is bainite, and it is distributed uniformly through the size of 460 mm×800 mm×3 200 mm.

关键词: NQP steel;large section plastic mould;temperature estimation;chemical composition;microstructure;machinability

Characterization of Free Cutting Phase in Free Cutting Stainless Steel Containing High Copper

GENG Hongming , WU Xiaochun , WANG Hongbin , MIN Yongan , ZHANG Hongkui

钢铁研究学报(英文版)

The machinability of 4Cr13 steel was improved obviously by adding Cu and S. The effect of copper addition on the machinability of 4Cr13 was similar to that of sulphur addition. By means of SEM, EBSD, and HREM, the distribution and size of the free cutting phase in the steel 4Cr13Cu were studied. The results showed that the free cutting phase was copperrich phase. The copperrich phases dispersed in the steel and were determined to have about 10 nm in diameter. The content of copper in the copperrich phase was over 70%.

关键词: machinability;copperrich phase;EBSD;HREM

Influence of Chemical Composition on Phase Transformation Temperature and Thermal Expansion Coefficient of Hot Work Die Steel

XIE Haojie , WU Xiaochun , MIN Yongan

钢铁研究学报(英文版)

On the basis of the uniform design method, six kinds of martensitic hot work die steels were designed. The phase transformation temperatures including Ac1, Ac3, and Ms were measured by DIL805A quenching dilatometer. The influences of the main elements on phase transformation temperatures were analyzed by quadratic stepwise regression analysis, and three corresponding equations were obtained. These equations, in which the interactions of the elements were considered, showed more effectiveness than the traditional ones. In addition, the thermal expansion coefficients of these steels in annealed state and quenched state were also obtained during the tests. The influences of chemical composition and temperature on the thermal expansion coefficient were analyzed; the equations obtained were verified by using several kinds of steels. The predicted values were in accordance with the results of the experiments.

关键词: phase transformation temperature;thermal expansion coefficient;hot work die steel;uniform design;quadratic stepwise regression analysis

THEREVERSSE TRANSFOR MATION OF THE STERSS INDUCEDεMIN FE 17MN 10CR 5SI 4NIALLOY

Q.S. Liu1 , 2 , 3) , L.C. Zhao3) , G.X. Dong2) and N.J. Gu1) 1) Heibei University of Technology , Tianjin 300130 , China 2) Tianjin Institute of Technology , Tianjin 300191 , China 3) Harbin University of Technology , Harbin 150001 , China

金属学报(英文版)

Theconstruction changinginthereversetransformation ofthestress induced εMin Fe 17 Mn 10 Cr 5 Si 4 Ni alloy is carefully inspected in transmission electron microscope, and then stress induced εM procedure of reverse transformation is analyzed. The behavior of reverse transformationisdissimilar when the organization of εMis different. The reversetransfor mation ofεM withtheshapeofsingle plateandstripisrelativelyeasy,anditsreversibilityincrystallographiciseasilytocarryout,fortheεM with multilayerstructure,thereversetrans formationtakes placein isolatedlayers, fortheεMthat grows well,thereversetransforma tion isrelatively difficult becauseofthe ductile harmonization between itsinternalorganiza tion structures.

关键词: stress induced εM , null , null

[C16min]Br修饰的多壁碳纳米管及其与低密度聚乙烯复合材料的制备及介电性能

徐佩 , 卢旭鑫 , 汪传斌 , 杨善中 , 孙晓红 , 丁运生

高分子材料科学与工程

为改善多壁碳纳米管(MWNT)在低密度聚乙烯(LDPE)中的分散性及复合材料的界面特性,采用溴化-1-十六烷基-3-甲基咪唑基离子液体([C16min]Br)对MWNT进行表面改性,并用Raman光谱对改性效果进行了表征.将经过修饰的碳纳米管(MIL)与LDPE熔融共混得到MIL/LDPE复合材料,采用场发射扫描电子显微镜(FESEM)和阻抗分析仪(LCR)对复合材料的结构与介电性能进行了分析.结果表明,相比与MWNT/LDPE(渗流阈值为5.2％,介电常数为82,介电损耗为0.93),MIL/LDPE(渗流阈值为9.1％,介电常数为169,介电损耗为0.51)介电常数增大,介电损耗降低.并且在低温时,MIL/LDPE介电常数随温度的变化甚小,显示出良好的温度-介电常数特性.

关键词: 咪唑基离子液体 , 碳纳米管 , 低密度聚乙烯 , 介电性能

住友金属用QSP工艺进行8m／min的高拉速试验

上海金属

关键词:

尼龙612的等温结晶动力学

王玉东 , 付鹏 , 李晓光 , 刘民英 , 赵清香

高分子材料科学与工程

用差示扫描量热(DSC)研究了尼龙612的等温结晶动力学.实验结果表明,在所研究的等温结晶温度范围内(184℃、186℃、188℃、190℃、192℃),尼龙612达到最大结晶速率时的时间、半结晶期和动力学结晶速率常数分别为:O.12min、0.19 min、0.22 min、0.29 min、0.59 min;0.15 min、0.22 min、0.24 min、0.33 min、0.64 min和22.03 min<'-1>、23.28min<'-1>、8.85 min<'-1>、5.15 min<'-1>、1.93 min<'-1>.等温结晶过程符合Avrmi方程,二次结晶现象不明显.在等温结晶过程中得到的Avrmi指数n在1.81～2.32之间,由理论分析可知,尼龙612等温结晶是一维生长和二维盘状生长.由Arrhenius方程求得尼龙612的等温结晶活化能ΔE=-209.5 kJ/mol.

关键词: 尼龙612 , 等温结晶动力学 , 结晶活化能

在不同时间下退火对非晶硅薄膜晶化的影响

靳瑞敏 , 陈兰莉 , 罗鹏辉 , 郭新峰 , 卢景霄

材料导报

用玻璃作衬底在不同温度下用PECVD法直接沉积非晶硅(a-Si∶H)薄膜,在400℃和500℃分别光退火5min、10min、20min、30min、40min、60min、120min,用拉曼光谱分析前后样品,发现随着晶化时间的延长晶化效果越好,500℃退火的薄膜比400℃的晶化效果好.

关键词: PECVD法 , 非晶硅薄膜 , 光退火晶化 , 拉曼光谱

冷却速度对T91相变速度和产物的影响

殷红旗 , 刘永长 , 宁保群 , 徐荣雷 , 张尧卿 , 韩雅静

材料科学与工程学报 doi:10.3969/j.issn.1673-2812.2007.01.030

本文研究了T91钢冷却过程中,不同冷却速度(10 k/min(200 k/min)对相变速度和产物的影响.研究表明不同的冷却速度生成的组织差别较大,在较低速冷却下(10 k/min和30 k/min)的组织为较多的先共析铁素体和板条马氏体,中速冷却(30 k/min和50 k/min)基本都为板条马氏体,在较高速冷却过程中(100 k/min和200 k/min)组织中除了板条马氏体还出现了片状马氏体,另外冷却速度还影响了相变开始点和相变速度.

关键词: T91 , 冷却速度 , 相变