材料期刊网

PREDICTION OF THERMODYNAMIC PROPERTIES OF THE FeO-CaO-SiO_2 MELTS FROM WILSON EQUATION

D.P.Tao and X.W. Yang(Department of Metallurgy , Kunming University of Science and Technology , Kunming 650093 , China)

金属学报(英文版)

An attempt was made to use the Wilson equation to predict the thermodynamic properties of the FeO-CaO-SiO2 melts at 1673 and 1873K. The activities of component FeO in the ternary melts at a given temperature were found to be conveniently calculated from the equation only with related binary parameters at different temperatures.The predicted values are in agreement with the ternary experimental data.

关键词: thermodynamic property , null , null

AZ91D镁合金化学镀Ni-P及Ni-W-P镀层的结构与耐蚀性

李端阳 , 沈波 , 任玉平 , 裴文利 , 杨中东 , 王继杰 , 秦高梧

中国腐蚀与防护学报

在AZ91D镁合金上直接化学镀Ni-P和Ni-W-P镀层，并利用扫描电子显微镜、X射线衍射仪及电化学工作站研究后续热处理对化学镀层组织形貌、相组成及其耐蚀性的影响。结果表明，制备的Ni-P镀层为非晶态，而Ni-W-P镀层为纳米晶结构，两者在3.5%NaCl水溶液中的耐蚀性相当。热处理可以明显提高Ni-W-P镀层的耐蚀能力，但却稍微弱化Ni-P镀层的耐蚀能力，热处理后的Ni-W-P层自腐蚀电位相对于未处理的化学镀Ni-W-P或Ni-P层提高了约150 mV。

关键词: AZ91D镁合金 , Ni-P coating , Ni-W-P coating , corrosion resistance

AZ91D镁合金化学镀Ni-P/Ni-W-P双层镀层研究

李光玉 , 程仲基 , 牛丽媛 , 连建设

材料科学与工艺

为了提高镁合金的耐磨耐蚀性,研究了一种镁合金直接化学镀Ni-P/Ni-W-P双层镀层的方法.采用扫描电镜(SEM)和X-射线衍分析射仪(XRD)分析了镀层的微观结构.对镀层进行了极化曲线分析,并进行了盐酸腐蚀试验和结合力试验.结果表明,该复合镀层组织致密无孔,具有较高的显微硬度和高耐蚀性.镀层硬度可达622 HKV,试样在10%的HCl溶液中可保持近3 h不腐蚀基体,对镁合金起到很好的保护作用.

关键词: 镁合金 , 化学镀 , Ni-W-P , AZ91D , 耐蚀性

Brief Outline of the Metallurgy Department of Kunming Institute of Technology

LIU Chunpeng Kunming Institute of Technology , Kunming 650093 , China.

材料科学技术（英文）

关键词:

Department of Metallurgy and Materials Engineering of Chongqing University

YAN Guangting Chongqing University , Sichuan , China.

材料科学技术（英文）

关键词:

Experimental and modeling investigation on SiC(p) distribution in powder metallurgy processed SiC(p)/2024 Al composites

Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing

SiC(p)/2024Al composites were fabricated through the powder metallurgy (PM) technique. The mixing process was modified by using a high ball to charge ratio (BCR), which resulted in improved homogeneity of the SiC(p) distribution, as well as enhanced tensile strengths of the as-pressed composites. A small particle size ratio of aluminum to SiC(p) (PSR) and extrusion also improved the uniformity of the SiC(p) distribution. The improvements by the three approaches were quantitatively analyzed using a critical volume fraction model. The model demonstrates that a small PSR and a large deformation ratio of aluminum particles were two essential factors of improving the homogeneity of the SiC(p). A homogeneity analysis using the Dirichlet Tessellation method provided an additional explanation for the model. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.

关键词: Analytical modeling;Metal-matrix composites;Powder metallurgy;Reinforcement distribution;aluminum-matrix composites;particle-size ratio;mechanical-properties;microstructure;reinforcement

Microstructure and Tensile Properties of ZK60 Alloy Fabricated by Simplified Rapid Solidification Powder Metallurgy (S-RS P/M) Process

Zhenya Zhang

材料科学技术（英文）

This study investigated the microstructures and mechanical properties of ZK60 alloy prepared by a simplified rapid solidification powder metallurgy (RS P/M) processing system (S-RS P/M), which consists of warm press in dry air and hot extrusion. Microstructure characterizations showed that S-RS P/M alloy consisted of magnesium matrix and oxide stringers of ~1 μm in width. TEM (transmission electron microscopy) observations illustrated nano-size magnesia particles (10{30 nm) constituted oxide stringer in detail. Due to a relatively higher volume of nano-size magnesia particle produced during S-RS P/M process, 0.2% yield strength of S-RS P/M ZK60 alloy was found to be as high as 382 MPa, which is 10% higher than that of RS P/M alloy. The improvement in mechanical properties is mainly attributed to the combination effects of Orowan mechanism and coe±cient of thermal expansion (CTE) mismatch because of the approximately same average grain size.

关键词: Microstructure

Constitutive flow behavior and hot workability of powder metallurgy processed 20 vol.%SiC(P)/2024Al composite

Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing

Constitutive flow behavior and hot workability of the powder metallurgy processed 20 vol.%SiC(P)/2024Al composite were investigated using hot compression tests. The modified Arrhenius-type constitutive equations were presented with the values of material constants in consideration as a function of strain. Dynamic material model (DMM) and modified DMM were used to construct the power dissipation efficiency maps, and Ziegler's instability criterion and Gegel's stability criterion were used to build instability maps. The presence of finer SiC(P) and more boundaries resulting from smaller 2024Al powders shifted the dynamic recrystallization domain of the 2024Al matrix to higher strain rate and lower temperature ranges and decreased the peak value of power dissipation efficiency. Large instable regions were found in the form of flow localization and cavitations located at the matrix/SiC(P) interfaces and within the SiC(P) clusters. By comparison, the Gegel's stability criterion was more sensitive to the instability zones than the Ziegler's instability criterion for this material. (c) 2010 Elsevier B.V. All rights reserved.

关键词: Metal matrix composites;Constitutive equations;Processing maps;Aluminum alloys;Powder metallurgy;6061+20-percent al2o3 composite;matrix composites;working;characteristics;deformation-behavior;al composite;maps;aluminum;20-percent;particles;extrusion

直流电沉积Ni-W-P镀层研究

刘殿龙 , 杨志刚 , 刘璐 , 张弛

稀有金属材料与工程

采用直流电沉积法,在低碳钢表面成功沉积Ni-W-P镀层.应用X射线荧光(XRF)、扫描电子显微镜(SEM)、俄歇电子能谱(AES)、X射线衍射(XRD)仪等方法,研究电流密度、镀液pH值和镀液温度对Ni-W-P镀层成分、表面形貌和结构的影响.结果表明,电流密度和镀液pH值的变化对Ni-W-P镀层成分的影响很大,而电流密度、镀液pH值和温度对镀层厚度的影响较小.电流效率随着电流密度和镀液温度的增大分别降低和升高,而随着镀液pH值的变化,在pH=7.0时有极大值.镀液pH值对Ni-W-P镀层结构有较大影响,在pH=8.0时,镀层呈现明显的Ni(111)峰,此时镀层硬度达到极大值7130 MPa.在此基础上,对Ni-W-P镀层的电沉积机制做了进一步探讨.

关键词: Ni-W-P镀层 , 电流密度 , pH值 , 镀液温度

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