材料期刊网

Glass Formation and Thermal Stability in Rapidly Solidified Al-Fe-V-Si Alloy with Misch Metal Additions

Jianqiang WANG , Meiguang ZENG (M.K.Tseng) and Xiufang CHEN(Dept. of Material Science , College of Science , Northeastern University , Shenyang 110006 , China)Lin DONG and Shixu GU(Liaoning Province Center of Analysis and Testing Research , Shenyang 110015 , Chi

材料科学技术（英文）

A new amorphous Al87.3Fe4.3V0.7Si1.7Mm6.0(Mm: misch metal) was prepared by using melt-spinning technique. Differential scanning calorimetry (DSC), X-ray diffraction (XRD). transmis-sion electron microscopy (TEM) and energy dispersive X-ray (EDX) have been used to investigatethe crystallization behaviour of thi5 amorphous alloy It is found that the crystallization processcan be concluded as follows: amorphous→ amorphous plus fcc-Al→ fcc-Al plus AI11(La,Ce)3plus i-phase (icosahedral)→ fcc-Al plus Al11(La,Ce)3 plus i-phase plus ic-phase (icosahedralcompounds). The results of microhardness measurement show that HV values are higher thanthose in Al-Fe-V-Si based alloy and the maximum HV value corresponds to the coexisting ofnanoscale Al particles and i-phase.

关键词:

Ion sputter erosion in metallic glass-A response to "Comment on: Homogeneity of Zr(64.13)Cu(15.75)Ni(10.12)Al(10) bulk metallic glass" by L-Y. Chen, Y-W. Zeng, Q-P. Cao, B-J. Park, Y-M. Chen, K. Hono, U. Vainio, Z-L. Zhang, U. Kaiser, X-D. Wang, and J-Z Jiang J. Mater. Res. 24, 3116 (2009)

Journal of Materials Research

The morphology of the dark and bright regions observed by transmission electron microscopy for the Zr(64.13)Cu(15.75)Ni(10.12)Al(10) bulk metallic glass strongly depends on the ion beam parameters used for ion milling. This indicates that the ion beam could introduce surface fluctuation to metallic glasses during ion milling.

关键词: room-temperature

Secondary M6C precipitation in K40S cobalt-base alloy

Materials Letters

Secondary M,C precipitation was investigated in K40S cobalt-base alloy after 100 h aging at 950 degreesC. The results showed that it was closely related to the tungsten-rich zones inherited from the as-cast condition and the degeneration of the primary M7C3 carbide. A direct element reaction, 6M + C --> M6C, in which C comes from the decomposition of the M7C3 carbides, is suggested as the mechanism of secondary M6C precipitation in K40S alloy. (C) 2001 Elsevier Science B.V. All rights reserved.

关键词: M6C precipitation;aging;M7C3 carbide;superalloy

Exact solutions of nonlinear dispersive K(m, n) model with variable coefficients

Applied Mathematics and Computation

The variable-coefficient Korteweg-de Vries (KdV) equation with additional terms contributed from the inhomogeneity in the axial direction and the strong transverse confinement of the condense was presented to describe the dynamics of nonlinear excitations in trapped quasi-one-dimensional Bose-Einstein condensates with repulsive atom-atom interactions. To understand the role of nonlinear dispersion in this variable-coefficient model, we introduce and study a new variable-coefficient KdV with nonlinear dispersion (called vc-K(m, n) equation). With the aid of symbolic computation, we obtain its compacton-like solutions and solitary pattern-like solutions. Moreover, we also present some conservation laws for both vc-K(+)(n, n) equation and vc-K (n, n) equation. (C) 2011 Elsevier Inc. All rights reserved.

关键词: Vc-K(m, n) equation;Nnonlinear dispersion;Symbolic analysis;Compacton-like solutions;Solitary pattern-like solutions;Conservation;laws;compacton solutions;solitary patterns;equations;solitons

Zn-5%Al合金超塑性的m-C-δ(或m-k-δ)关系

刘勤 , 夏锄 , 刘晓东

金属学报

在170,190,210,230,250℃的温度下,采用3.7×10~2,7.4×10~2和1.1×10~(-1)min(-1)的应变速率(平均)对Zn-5%Al共晶合金的m-C-δ(或m-k-δ)关系曲线(简称m-δ关系曲线)进行了测定.所有的曲线均随应变的δ增加而快速上升.俟达到某一定的应变量(极限应变量δ1)后。开始缓慢下降并保持平稳直至断裂.Zn-5%A1共晶合金的m-δ关系曲线不存在k_(?)=k_I(k_(I 1),k_(I 2),k_(I 3),……)=k_F(或C_0=C_I(C_(I 1),C_(I 2),C_(I 3),……)=C_F=1)的简单情况.可应用m-δ方程式[4,5]对曲线上各点C值(包括所有的C_I和C_F值)进行计算.C值随δ值的增加成近似的直线上升.直线的斜率在极限应变(δ1)处突然减小.

关键词:

Chen系统的状态变量周期性反馈控制

李开明 , 李亚洲 , 冯维贵 , 林长

量子电子学报 doi:10.3969/j.issn.1007-5461.2007.05.014

采用非线性反馈控制,用附加了带参数的正弦项对Chen系统进行了有效的控制.随着参数k的逐渐增大,系统的动力学行为呈现出一系列的变化.数值研究结果表明:随控制参数的增大,驱动信号的强度渐大,混沌系统由混沌运动到周期轨道,最终到一相点.

关键词: 混沌 , Chen系统 , 不动点 , Lyapunov指数 , 反馈控制

用DEPT135测定Resol的组成及微细结构参数

杨金瑞 , 余尚先 , 顾江楠

高分子材料科学与工程

通过对resol(羟甲基酚化合物和低分子量羟甲基酚树脂)DEPT135图谱的分析讨论,得到一系列计算resol微细结构参数的经验公式.根据DEPT135图谱可判断是否发生缩聚反应,根据经验公式可计算酚单体各个活性点参与反应百分率或酚羟基导入率、不同类型缩聚所占百分率及低分子量羟甲基酚树脂的平均核体数.

关键词: 羟甲基酚化合物 , 羟甲基酚树脂 , DEPT135 , 结构参数

V-M(M=Li,Na,K,Sc,Ag)二元系的相图热力学研究

胡标 , 尹明 , 王庆平 , 闵凡飞 , 杜勇

兵器材料科学与工程

基于文献报道的实验数据,采用相图计算(CALPHAD:CALculation of PHAse Diagrams)方法对V-M(M=Li,Na,K,Sc,Ag)5个二元系进行相图热力学研究.通过热力学优化计算获得了一套描述液相、(V)、(Li)、(Na)、(K)、(αSc)、(βSc)和(Ag)相的热力学参数.V-Li、V-Na和V-K体系中的气相视为由组元V、Li、Li2、Na、Na2、K和K2混合的理想气体.与实验相图数据对比表明,获得的热力学参数能够准确地描述实验相平衡数据.

关键词: V-M(M=Li,Na,K,Sc,Ag) , CALPHAD方法 , 相图 , 热力学模型

Thermoelectric Characterization of (Na1-yMy)1.6Co2O4 (M=K, Ca, Sr)

Ying LI

材料科学技术（英文）

Oxide materials NaCo2O4 and (Na1-yMy)1.6Co2O4 (M=K, 0.05≤y≤0.35; M=Ca, Sr, 0.10≤y≤0.40) were prepared by a sol-gel method. Experimental results indicated that the Seebeck coefficient and the Power-factor of Na Co2O4 were improved by doping Ca and Sr but not by K. The Power-factor of NaCo2O4 is in its maximum, 1.68×10-4 W•m-1•K-2 and 11% bigger than that of the original one when the dopant fraction of Ca was 0.1. Doping Sr makes NaCo2O4 have the biggest Power-factor, 1.68×10-4 W•m-1•K-2 that is 50% bigger than the non-doping oxide. The experimental results indicate that suitable dopants and addition amounts could improve the thermoelectric properties of NaCo2O4 greatly.

关键词: Thermoelectric materials , materials , Electric , proper

Stereology in Materials Science

LIU Guoquan Department of Materials Science and Engineering , University of Science and Technology Beijing , 100083 , China.

材料科学技术（英文）

Quantitative analysis of populations having a geometric structure,which has developed into a special scientific subject called microstructology or stereology,is of great importance to the characterization and evaluation of microstructures and their evolution in various processes.This paper, besides a brief discussion on those topics such as the recent developments of computer assisted image analysis,mathematical morphology,and fractal analysis,will mainly focus on the scope,fundamen- tals,present status,and perspectives of classical stereology.Several case examples of its application to materials science will also be given.

关键词: stereology , null , null , null