张鸿冰
,
倪乐民
,
徐祖耀
金属学报
经 LFG(ΔG~(γ→a))-Mogutnov(ΔG_(Fe)~(γ→a))、徐祖耀(Shu-A)(ΔG~(γ→a))-Orr-Chipman(ΔG_(Fe)~(γ→a))、徐祖耀(Shu-B)(ΔG~(γ→a))-Orr-Chipman(ΔG_(Fe)~(γ→a))组合,均可算得 Fe-Mn-C 合金的 Ms 温度且与实验值十分符合.所得结果经数学处理,得 Fe-Mn-C 系 Ms 与成分的关系为:Ms(K)=817.4-7513.4xc-4141.9x_(Mn)-32083.5x_Cx_(Mn)(LFG)Ms(K)=829.9-7580.5x_C-4166.0x_(Mn)-15727.8x_Cx_(Mn)(SHU-A)Ms(K)=829.2-7276.1x_C-2915.4x_(Mn)-43825.7x_Cx_(Mn)(SHU-B)其线性相关系数均大于0.992.C 和 Mn 浓度均使合金的 Ms 线性地降低,而碳的作用几乎是Mn 的两倍.处理中引入了合金元素交互作用项(x_Cx_(Mn)),表明 C,Mn 相互加剧对 Ms 的影响。随含 C,Mn 量的增加,相变驱动力均单调地增加,而不存在奇异点.Ms 和相变驱动力的计算值均依赖于ΔG_(Fe)~(γ→a)项.
关键词:
徐卫兵
,
戈明亮
,
何平笙
应用化学
doi:10.3969/j.issn.1000-0518.2001.09.011
用熔融插层法制备聚甲醛/蒙脱土纳米复合材料,用X射线衍射研究聚甲醛及复合材料的微观结构,表明复合材料是纳米复合材料.用DSC法研究其非等温结晶行为,对所得数据分别用Jeziorny法、Ozawa法和Liu法进行处理.结果表明,Jeziorny法和Liu法处理非等温结晶过程比较理想.聚甲醛及聚甲醛/有机蒙脱土纳米复合材料的结晶活化能分别为334.6和196.9 kJ/mol,说明有机蒙脱土的加入,降低了聚甲醛的结晶活化能,且t1/z缩短,起到了异相成核的作用.
关键词:
聚甲醛
,
蒙脱土
,
纳米复合材料
,
非等温结晶动力学
王平华
,
徐国永
应用化学
doi:10.3969/j.issn.1000-0518.2004.08.007
用熔融复合法制备聚丙烯/凹凸棒土纳米复合材料,用DSC法研究其非等温结晶行为,对所得的数据分别用Jeziorny法、Ozawa法和Liu法进行处理.结果表明,Jeziorny法和Liu法处理非等温结晶过程比较理想.聚丙烯及聚丙烯/凹凸棒土纳米复合材料的结晶活化能分别为194.1和162.8 kJ/mol,表明凹凸棒土的加入,降低了聚丙烯的结晶活化能,且t1/2缩短,起到了异相成核作用.
关键词:
聚丙烯
,
凹凸棒土
,
纳米复合材料
,
非等温结晶动力学
Journal of Materials Processing Technology
The crystallization temperatures and other thermal properties have been measured systematically for two ternary Cu-Ni-P and two quaternary Cu-Ni-Sn-P amorphous systems. The dependence of crystallization temperature on the composition for the four alloy systems can not be described basically by the usual used Naka rule. The Gibbs free energy of crystallization can be calculated for the alloy systems with the model proposed by Shu et al. Using the calculated free energy of crystallization, it is still not possible to properly describe all of the crystallization temperatures of the alloy systems. However, it has been found that the correlation between the crystallization temperature and the content of the alloy systems can be reasonably explained by the nucleation and growth rates of a new phase for the classical theory of phase transformation. It has been established that the classical theory of phase transformation can be used to describe the thermal stability of the Cu-based amorphous alloys during their crystallization process. (C) 1999 Published by Elsevier Science S.A. All rights reserved.
关键词:
thermal stability;amorphous alloys;Cu-P based alloy systems;classical;theory of phase transformation;solid-liquid interface;structural model;glasses
盖红星
,
李建军
,
韩军
,
邢艳辉
,
邓军
,
俞波
,
沈光地
,
陈建新
量子电子学报
doi:10.3969/j.issn.1007-5461.2005.01.016
采用Shu Lien Chuang方法计算了AlInGaAs/AlGaAs应变引起价带中重、轻空穴能量变化曲线,在Harrison模型的基础上详细地计算了AlInGaAs/AlGaAs和GaAs/AlGaAs量子阱电子、空穴子能级分布并且进一步研究了这两种材料在不同注入条件下的线性光增益.进一步计算比较可以得出AlInGaAs/AlGaAs应变量子阱光增益特性要优于GaAs/AlGaAs非应变量子阱增益特性,因此AlInGaAs/AlGaAs应变量子阱半导体材料应用于半导体激光器比传统GaAs/AlGaAs材料更具优势.
关键词:
光电子学
,
应变量子阱
,
光增益
,
AlInGaAs
,
半导体激光器
袁训锋
,
丁雨田
材料导报
采用Tong和Beckermann等提出的耦合流场相场模型对纯镍凝固中多晶粒枝晶的生长过程进行模拟,研究了多晶粒枝晶的生长形貌和温度分布.结果表明,熔体流动显著改变凝固前沿的传热,从而影响枝晶生长.受熔体流动和多晶粒之间相互影响的共同作用,枝晶在4个最优生长方向上的形貌呈现不对称;熔体流动还改变了枝晶的水平最优生长方向,使得水平主枝向上游倾斜;此外,二次枝晶出现径向熔化和轴向熔化等粗化方式.
关键词:
相场法
,
强制对流
,
多晶粒
,
凝固
Author X.A. Zhang1)
,
H.Q. Xia1)
,
Z.T. Wu1)
,
Y.F. Han1)
,
R. Shi2) and G.X. Hu2) \= 1) Mechanical Properties Laboratory
,
Beijing Institute of Aeronautical Materials
,
Beijing 100095
,
China2) The State Education Commission Open Research Laboratory for High Temperature
金属学报(英文版)
Materials and Testing, Shanghai Jiao Tong University, Shanghai 200030, ChinaManuscript received 18 October 1998 The threestage creep behavior of DD3 single crystal superalloy had been studied. The results show that the creeprupture properties of DD3 single crystal satisfy the requirements for high performance turbine blade application. The influence of crystal orientation on the creeprupture property of DD3 single crystal was tested and discussed. An engineering criterion to evaluate the regimes of secondary and tertiary creep is proposed, and this method gives a reasonable result for practical applications. The fractography and TEM micrography of the tested specimens had been studied, and it is determined that the glidecontrolled creep is the basic creep mechanism of DD3 single crystal at intermediate temperature, but the thermally activated processes become dominant at higher temperature.
关键词:
threestage creep curve
,
null
,
null
,
null
Journal of the American Chemical Society
In this communication, we demonstrate nonmetal SiO(x) nanoparticles (NPs) can tailor few-layer graphenes (FLGs) into graphene nanoribbons (GNRs) and regular pieces with smooth edges. The tailoring of graphene is realized by the movements of SiO(x) NPs along the graphene lattice in the atmosphere of H(2), and the tailored trenches exhibit high selectivity of the crystallographic orientation compared to the reported metal. NPs. The low tailoring rate and the tong lifetime provide great potential for accurate control of the trench length or the length of the tailored GNRs. As a result, smooth GNRs with a length of several micrometers and a width narrower than 10 nm are obtained. A catalytic hydrogenation mechanism is proposed for the tailoring of graphene by SiO(x) NPs. These findings open up the possibility for atomically precise graphene device fabrication without metal, contamination and indicate the potential catalytic activity of nonmetal Nips for the hydrogenation of carbon materials.
关键词:
nanoribbons;hydrogenation;graphite
