材料期刊网

STUDY ON C FIBER REINFORCED CELSIAN MATRIX COMPOSITES

X.W.Yin , L.F.Cheng , L.T.Zhang , W.C.Zhou and Y.D.Xu State Key Laboratory of Solidification Processing , Northwestern Polytechnical University , Xi′an 710072 , China

金属学报(英文版)

Strong, tough, and almost fully dense C fiber reinforced celsian matrix composites have been fabricated by impregnation of the fiber tows with the matrix slurry, winding on a drum, drying, stacking the prepreg tapes in the desired orientation, and hot pressing. The monoclinic celsian phase in the matrix was produced in situ, during hot pressing, from amphosous BAS. The unidirectional composites having ≈20 vol% of fibers exhibited graceful failure with extensive fiber pullout in three point bend tests at room temperature. Values of ultimate flexural strength and fracture toughness were 379MPa and 8 3MPa·m 1/2 , respectively.

关键词: barium aluminosilicate , null , null , null , null

Thermal transport properties and electronic structure of W-doped rubidium blue bronzes Rb(0.3)Mo(1-x)W(x)O(3) (x=0, 0.001, 0.003, 0.005)

Physica B-Condensed Matter

The thermoelectric power (TEP), electrical resistivity and X-ray photoemission spectrum (XPS) of the W-doped rubidium blue bronzes Rb(0.3)Mo(1-x)W(x)O(3) (x=0, 0.001, 0.003, 0.005) were investigated. It is shown that the Peierls transition is suppressed with the increase in the concentrations of the doped W ions. The sign change of the TEP was observed for all the samples. At low temperature below the Peierls transition, the W-doping makes the obvious decrease in the absolute values of TEP, especially for Rb(0.3)Mo(1-x)W(x)O(3) (x=0.003, 0.005). Furthermore, as compared with the pure blue bronzes, the enlarged difference between Peierls transition temperature (T(p)) and the sign changed temperature (T(s)) in Rb(0.3)Mo(0.999)W(0.001)O(3) bronzes was observed and discussed in detail. (C) 2010 Elsevier B.V. All rights reserved.

关键词: Charge density wave;Blue bronze;Thermoelectric power;Resistivity;charge-density-wave;thermoelectric-power;oxide bronzes;k0.3moo3;transition;scattering;rb0.3moo3;state;impurities;k0.30moo3

Amorphous forming ability of Co-X(X=Cr, Mo, W)  magnetic thin films

Gaowu QIN

金属学报(英文版) doi:10.1016/S1006-7191(08)60117-9

Co-X(X=Cr, Mo, W) magnetic thin films were prepared by using DC magnetron sputtering, and their structures were examined by using X-ray diffraction (XRD). The amorphous forming ability (AFA) of the three alloy systems was discussed based on thermodynamic calculation and experiments. The results show that the Co-Mo thin films exhibit the largest AFA among them, and the Co-W thin films are condition-dependent amorphous while the Co-Cr thin films are hard to be amorphous, which is consistent with the thermodynamic calculation. The difference in AFA for the alloys of these three systems is finally ascribed to three main factors: differences in electronegativity, electron density and atomic size between Co and X elements.

关键词: Amorphous forming ability , Co-Cr , Co-Mo , Co-W

过渡金属元素 X（X ＝W，Mo，Cr）对 RuAl合金抗氧化性影响的机理

袁江 , 宋新华 , 孙甲尧 , 龚航

航空材料学报 doi:10.11868/j.issn.1005-5053.2016.1.001

基于密度泛函理论的第一性原理，通过计算 RuAl 合金氧化物 Al2 O3和 RuO2的氧化能，考察过渡金属元素 X （X ＝W，Mo，、Cr）加入到 RuAl 合金后的占位及对氧化物 Al2 O3和 RuO2的结构稳定性影响。研究表明：经过渡金属元素 X 合金化后，Al2 O3和 RuO2的氧化能均有所增大，增大 Al2 O3氧化能的顺序为：W ＞Mo ＞Cr；增大 RuO2氧化能的顺序为：Mo ＞Cr ＞W，且 RuO2氧化能增大幅度大于 Al2 O3。通过态密度、电荷密度等因素的分析，阐明了 W 对提高 RuAl 抗氧化性能的根本原因是降低了 Al-O 和 Ru-O 的共价键特性，增加了 Al-O 和 Ru-O 的离子键特性；金属元素 X（X ＝W，Mo，Cr）可阻碍 RuAl 金属化合物发生内氧化过程，有利于在 RuAl 表面层的横向方向上形成连续性致密的 Al2 O3氧化层。

关键词: RuAl , 第一原理 , 抗氧化性能 , 稳定性 , 氧化能

(Mo_(1-x),W_x)Si_2固溶体的价电子结构及其性能研究

彭可 , 易茂中 , 冉丽萍 , 葛毅成

稀有金属材料与工程

根据固体与分子经验电子理论(EET),利用平均原子模型对(Mo_(1-x),W_x)Si_2)固溶体进行价电子结构分析,并分别与MoSi_2和WSi_2基体进行比较.结果表明,随着x值的增加,(Mo_(1-x),W_x)Si_2固溶体的主干键络键能、最强键上共价电子数和共价电子总数百分比均逐渐增加,表明固溶体的熔点、硬度和强度均逐渐增加.

关键词: (Mo_(1-x) , W_x)Si_2固溶体 , 价电子结构 , EET理论 , 性能

X射线荧光测定复式碳化物中W、Ti、Ta、Fe方法研究

颜晓华 , 彭宇 , 苏明

硬质合金 doi:10.3969/j.issn.1003-7292.2015.04.008

复式碳化物是一种硬质合金行业和其他新材料行业广泛使用的原料,常用的复式碳化物由TiC、WC、TaC等固溶生成.本方法以m(Li2B4O7)∶m(LiBO2)=67∶33为熔剂制备复式碳化物的熔融玻璃片,采用Bruker公司的S8 Tiger型顺序式X射线荧光光谱仪和Spectra plus基体效应校正等软件,在熔融条件、标样的设置、转换系数的计算、仪器条件等方面进行探讨,建立了X射线荧光光谱仪测定复式碳化物中W、Ti、Ta、Fe的含量方法,方法分析测定范围(氧化物)W 25.55％～52.41％、Ti 8.89％～31.48％、Ta 15.03％～28.54％、Fe 0.032％～ 1.07％,结果表明,方法的精密度和准确度较好.

关键词: 复式碳化物固溶体 , 化学分析 , X射线荧光光谱 , W , Ti , Ta , Fe

电沉积Ni-W合金镀层的X射线光电子能谱分析

王宙 , 许光宇 , 王金玉 , 杨德庄

材料保护 doi:10.3969/j.issn.1001-1560.2002.04.013

采用X射线光电子能谱(XPS)对电沉积Ni-W合金镀层表面膜进行了分析.研究结果表明,Ni-W合金镀层表面存在一层薄的氧化膜,而钨的氧化作用远大于镍,Ni-W合金镀层中W含量的提高对耐蚀性起决定作用.

关键词: 电沉积 , Ni-W合金镀层 , X射线光电子能谱

X-ray powder diffraction data for Al-Cu-W phases

Powder Diffraction

Ternary Al-Cu-W alloys were investigated. The previously reported Al(3)Ti-type phase (space group 14/mmm) with the average composition Al(67)Cu(11.5)W(21.5) was found to have a=3.7296(4) angstrom and c=8.3797(10) angstrom. The ternary phase forming around Al(67)Cu(21)W(12) has a hexagonal structure with a=8.6594(13) angstrom and c=15.2677(21) angstrom. (C) 2011 International Centre for Diffraction Data. [DOI: 10.1154/1.3549770]

关键词: Al-Cu-W;powder X-ray diffraction;system

La_2Mo_(2-x)W_xO_9的氧离子扩散和相变机制研究

李丹 , 李相虎 , 方前锋

材料导报

采用介电弛豫和内耗技术,并结合XRD技术研究了新型氧离子导体La_2Mo_(2-x)W_xO_9(x=0、0.25、0.5、0.75、1.0、1.2、1.4)的氧离子扩散行为和相变机制.结果表明,在La_2Mo(2-x)W_xO_9的介电损耗-温度谱和内耗-温度谱上均出现了2个损耗峰,其中低温峰对应氧离子的扩散弛豫过程,高温峰对应氧离子/空位分布的静态无序态到动态无序态的转变.

关键词: 氧离子导体 , 介电弛豫 , 内耗 , 相变

Co-9Al-(9-x)W-xMo-2Ta-0.02B (x=4,9)合金的显微组织与高低温拉伸性能

丰革 , 李浩 , 樊非 , 李树索 , 沙江波

稀有金属材料与工程

以Co基高温合金Co-9Al-9W-2Ta-0.02B成分为基础,分别添加了4at％和9at％的Mo元素替代W(使W+Mo含量为9at％),用电弧熔炼法制备了Co-9Al-xMo-(9-x)W-2Ta-0.02B合金(x=4,9),分别称为4Mo和9Mo合金,研究了Mo含量及时效温度对合金相组成、显微组织形貌和高低温拉伸性能的影响.结果表明:铸态合金由Co的固溶体γ相基体和金属间化合物γ'相Co3(Al,Me)组成(其中Me为合金元素W、Mo、Ta),γ’相位于y相界.1350℃/8 h固溶+800C/100h时效处理的4Mo合金γ相中均匀析出了与之共格并规则排列的立方形γ’相Co3(Al,Me),γ’相尺寸为200～300 nm；9Mo合金析出大量胞状和针状的κ-Co3Mo相以及少量的y’相.1350℃/8 h固溶+900℃/100h时效处理时4Mo合金的γ/γ’共格组织中也析出微量针状κ-Co3Mo相,而9Mo合金中的针状相明显粗化.4Mo合金的高低温抗拉伸强度与塑性均高于9Mo合金,合金在600℃以上发生反常屈服.

关键词: 新型Co基合金 , 时效处理 , 相组成 , 显微组织 , 高温低力学性能