材料期刊网

Effect of Nb on Microstructure and Mechanical Properties in Non-magnetic High Manganese Steel

Jia-li CAO , Ai-min ZHAO , Ji-xiong LIU , Jian-guo HE , Ran DING

钢铁

关键词:

Novel Reduced-friction Materials by Laser Cladding of Copper Alloy on Cast Iron

Xichen YANG Milin ZHONG Tianxi ZHENG Naikun ZHANG Laser Processing Lab. , Tianjin Institute of Textile Science and Technology , Tianjin , 300160 , China

材料科学技术（英文）

Copper alloys suitable for laser cladding on cast iron are selected trom rune types of conventional powders. There are a poor spreading ability and porosity of copper alloy over the surface of castiron. Copper alloy surface is easily oxidized in atmosphere. These shortages have been overcome by ad- ding deoxidizers of Si and H_3BO_3. Laser parameters, stress and coefficient of friction have been ex- amined, and the larger smooth surface of Cu/cast iron for friction by laser cladding has been made for the application of the guide shoes of machine.

关键词: laser cladding , null , null

丙烯酸与丙烯腈感光共聚合反应研究

喻发全 , 刘艳萍 , 黄世英 , 姚树人

高分子材料科学与工程

采用McGiniss改良膨胀计与SW-1型微位移测量仪,测定了丙烯酸(AA)-丙烯腈(AN)感光共聚合速率;用102-G气相层析仪及1106型元素分析仪对AA-AN感光聚合体系的单体浓度比及共聚物链节比进行了定量分析,按假定的反应机理计算了单体的竞聚率,在40 ℃时的结果为rAA=2.85,rAN=0.038.

关键词: 丙烯腈 , 丙烯酸 , 紫外光 , 感光共聚 , 动力学 , 竞聚率

环氧树脂中电树枝生长特性及其动力学模型的实验验证

杨文虎 , 易冉 , 徐阳 , 惠思思 , 曹晓珑

绝缘材料 doi:10.3969/j.issn.1009-9239.2012.01.014

研究了不同外施工频电压下环氧树脂绝缘中的电树枝结构、生长的特性,并用Ding等提出的模型解释了电树枝的发展过程,模拟了其生长曲线.结果表明:在同一电压下,环氧树脂中电树枝的生长速度基本为恒定值,随外施电压的升高,电树枝分枝变少,生长速度基本呈指数增加,且利用模型模拟的生长曲线与实验测试的结果吻合,最后讨论了模型的物理基础.

关键词: 电树枝 , 环氧树脂 , 劣化 , 动力学 , 模型 , 模拟

Miedema模型在含O和S熔体与合金中的扩展与应用

陈伟亮 , 张宁 , 唐昭辉 , 丁学勇

材料研究学报

将Miedema模型与实验数据相结合得到适于Miedema模型的O和S的参数(O:电负性7.04、电子密度6.03、摩尔体积4.59;S:电负性5.8、电子密度3.24、摩尔体积6.97),计算了141种O的二元化合物和145种S的二元化合物生成焓其平均绝对误差(MAPE)分别为36.8％、32.4％.结合Ding导出的三元系相互作用系数计算模型,计算了1873 K时Fe基熔体中O和S与其它元素之间的相互作用系数.与实验数据的比较表明,除个别元素外,计算值与实验值之间误差不大且变化趋势比较一致.将误差较大的Nb、Ag、Pt的电负性参数由原来的4.05、4.35、5.65修正为4.31、4.17、5.57,使用Miedema模型的计算精度有很大的提高.

关键词: 材料科学基础学科 , Miedema模型 , 含O和S熔体与合金 , 相互作用系数 , 参数的修正

不同共聚体系对丙烯腈与丙烯酸单体竞聚率的影响

陈厚 , 刘军深 , 曲荣君 , 纪春暖 , 王成国 , 蔡华甦

高分子材料科学与工程

采用Kelen-Tudos方法, 测定了丙烯腈(AN)与丙烯酸(AA)共聚合反应体系中单体竞聚率,探讨了不同反应体系对单体竞聚率的影响.结果表明,在水相悬浮聚合体系中,当转化率小于20%时,两单体的竞聚率同DMSO均相溶液聚合结果相近;随转化率的增加,AN竞聚率增加,AA竞聚率减小,当转化率超过50%后,两单体竞聚率变化不明显.在H2O/DMSO混合溶剂沉淀聚合中,当水含量超过80%后,两单体竞聚率向水相悬浮聚合结果靠近.随溶剂极性增大,rAN与rAA值均减小.

关键词: 共聚反应 , 动力学 , 竞聚率

充填管道布置方案优化中的数值模拟分析

羊羽翔 , 付建新 , 宋卫东

黄金 doi:10.11792/hj20140808

矿山在充填管道布置方案中参数的选取往往通过经验公式估算，而目前尚无精确解的计算方法。但参数的选取恰当与否直接影响到矿山充填系统的效率以及使用寿命，因此参数选取的精确化便显得尤为重要。以石人沟铁矿的充填系统为工程背景，应用ANSYS分析软件中的FLOT-RAN CFD模块建立管道模型，分析了管道系统采用不同充填倍线时流速与压力的关系，并据此对充填倍线的理想值进行了分析计算，最终得出充填倍线为3．5，符合经验值的取值范围，对矿山充填管道布置方案有一定借鉴意义。

关键词: FLOTRAN CFD模块 , 充填倍线 , 管道模型 , FLUD141单元 , 方案优化

Effects of preparation technology on the structure and amorphous forming region for electroless Ni-P alloys

Journal of Materials Processing Technology

This paper has studied systematically the preparation technology and its effects on the structure and amorphous forming region (AFR), and theoretical description of the AFR for electroless Ni-P alloys. It has been found that the deposition rates increase and approach a maximum value and then decrease with the increase in the concentration of nickel chloride, sodium hypophosphite and pH value, respectively. However, the deposition rates decrease with the increase in sodium citrate. The AFR is P > 9-10 at.% in the range of concentration of nickel chloride studied. In the ran-e of concentration of sodium hypophosphite studied, there was no crystalline structure observed. The AFR calculated theoretically using the Miedema model was in good agreement with the experimental results. (C) 2002 Elsevier Science B.V. All rights reserved.

关键词: electroless Ni-P alloys;preparation technology;structure;amorphous;forming region;Miedema model;formation enthalpies;nickel deposition;mechanism

Thermodynamic predictions of Mg-Al-Ca alloy compositions amenable to semi-solid forming

International Journal of Materials Research

Thermodynamic prediction based oil a two-stage simulation has been carried out to investigate the composition range of Mg-Al-Ca alloys amenable to semi-solid forming. The results show that increasing the solute elements decreases the temperature sensitivity, but their effects oil the solidification ran-e are greatly different. In some Mg-Al-Ca alloys, the highest knee point in the liquid fraction vs. temperature Curve IS generated by the formation of Al(2)Ca phase. Several critical sections of the Mg-Al-Ca ternary system are also given. The criteria for semi-solid formability are identified and a range of compositions for Mg-Al-Ca alloys are evaluated in relation to these criteria. By comparing with A356 alloy and AZ91 alloy, a typical Mg-Al-Ca alloy AC74. is predicted to exhibit good semi-solid formability comparable to A356 and much better than AZ91.

关键词: M-Al-Ca magnesium alloy;Thermodynamic prediction;Alloy composition;selection;Semi-solid forming;az91d magnesium alloy;mechanical-properties;phase-equilibria;earth-elements;creep-behavior;zn alloys;microstructure;system;state

丙烯腈与N-乙烯基吡咯烷酮共聚体系对单体竞聚率的影响

陈厚 , 王成国 , 张旺玺 , 蔡华甦

高分子材料科学与工程

利用Kelen-Tudos方法测算丙烯腈(AN)与N-乙烯基吡咯烷酮(NVP)自由基共聚合单体竞聚率,研究了不同反应体系对单体竞聚率的影响.结果发现:在水相悬浮聚合体系中,转化率小于18%时,两单体的竞聚率同DMSO均相溶液聚合结果相近;转化率较大时,同溶液聚合结果偏差较大.H2O/DMSO混合溶剂悬浮聚合时,当水含量超过60%(质量比)后,单体竞聚率向水相悬浮聚合结果靠近.溶剂的极性增大,rAN与rNVP值均减小.随反应温度升高,共聚反应向理想共聚方向进行.

关键词: 丙烯腈 , N-乙烯基吡咯烷酮 , 竞聚率