材料期刊网

Fracture Toughness of Cast Al-Zn-Mg Alloys

K.H. W.Seah(Dept. of Mech. Eng. , National University of Singapore , Singapore 0511)S. C. Sharma (To whom correspondence should be addressed)(Dept. of Mech. Eng. , R.V.College of Engineering , Bangalore-560-059 , Karnataka , India)

材料科学技术（英文）

Compact tension specimens of as-cast Al-3Zn-2Mg and Al-7Zn-2Mg (in wt pct) alloys were subjected to fracture toughness tests at room temperature according to specification5 laid down in ASTM E-399-81. It was found that increasing the Zn content, grain refinement and increasing the solidification rate lead to an increase in the fracture toughness of the material.

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Preface to Special Issue on Photocatalysis for celebrating the 20th anniversary of Professor Jimmy C. Yu’s return to Hong Kong and leading photocatalytic research there

催化学报 doi:10.1016/S1872-2067(15)61006-3

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Fatigue crack initiation and fracture behavior of a copper bicrystal with a perpendicular grain boundary

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

By cyclically deforming a [(5) over bar 913]perpendicular to[(5) over bar 79] copper bicrystal with a perpendicular grain boundary (GB), the fatigue crack initiation and fracture behavior were investigated. It was found that only the primary slip systems were activated on both G1[(5) over bar 913] and G2[(5) over bar 79] grains including the vicinity of the GB at axial plastic strain range of 1.8 x 10(-4)-2.56 x 10(-3). By observing the surface and fractography, it was confirmed that the fatigue cracks always nucleated and propagated along the GB, and displayed an obvious tendency on different surfaces. On the front surface of the bicrystal, the intergranular cracking was more preferential than that on the lateral surface, even though the geometrical conditions among PSB, GB and stress axis on the lateral surface claimed to enhance cracking are more close to those proposed by Christ (Mater. Sci. Eng. A117 (1989) L25). Based on the experimental results above, the effect of the interaction of PSB with GB and stress axis on intergranular fatigue cracking in the bicrystal is discussed. It is suggested that Christ's geometrical conditions for intergranular cracking might be further developed and the plastic strain incompatibility near the GB should play a more important effect on intergranular fatigue cracking. (C) 1999 Elsevier Science S.A. All rights reserved.

关键词: copper bicrystal;cyclic deformation;grain boundary;fractography;intergranular cracking;nucleation

Ba在C2S-C3S矿物相中固溶机理探讨

陈树东 , 项建明 , 王晓翠 , 洪笑

硅酸盐通报

以Ca(OH)2、SiO2、Fe2O3、Al2O3化学纯为原料,分别掺入不同质量分数的Ba(OH)2制备不同矿物相组成的熟料相,运用化学分析、XRD、SEM、水化热测试方法,研究掺Ba(OH)2后熟料相中硅酸三钙-硅酸二钙(C3S-C2S)混合相组成、晶型、新相生成的变化规律.结果表明:Ba(OH)2一定程度上削弱C3S形成,且稳定β-C2S形成效应明显,矿物相体系中α'-C2S、α-C2S量减少并转换为β-C2S,掺量大于2.5％后有新相Ba0.48 Ca1.52SiO4形成;Ba(OH)2掺入促使矿物相中C2S相明显增多,晶粒整体尺寸变小,边界变圆润;随Ba(OH)2掺量递增,熟料样的水化速率呈持续减小的趋势变化.

关键词: C3S相 , β-C2S , 水化速率 , 水化

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

Corrosion behaviour of carbon steel in different concentrations of HCl solutions containing H(2)S at 90 degrees C

Corrosion Science

The corrosion behavior of SAE-1020 carbon steel in H(2)S-containing solutions with different concentration of HCl at 90 degrees C was investigated by weight loss, electrochemical measurements, SEM and XRD analysis. The results showed that the corrosion rate of carbon steel increased with increasing HCl concentration. Uniform corrosion was found on the carbon steel surface in H(2)S + HCl solutions, while corrosion cavities were observed in the solution only containing H(2)S. The ratio of Faradaic process of total corrosion process increased with the increase of HCl concentration. The corrosion products were solely composed of mackinawite in the H(2)S-containing solutions with or without HCl. (c) 2011 Elsevier Ltd. All rights reserved.

关键词: Steel;Weight loss;EIS;SEM;XRD;Acid corrosion;acidic chloride solutions;hydrogen-sulfide;aqueous-solution;iron;sulfides;electrochemical-behavior;media;dissolution;impedance;polarization;environments

P2O5对C6A4MS-C2S-C4AF系中β-C2S稳定作用研究

马德伟 , 杨利群 , 徐先宇

材料科学与工程学报 doi:10.3969/j.issn.1673-2812.2001.02.020

本文研究了C6A4MS-C2S-C4AF系中R2O5对β-C2S的稳定性问题.结果表明:P2O5的掺入能有效抑制β-C2S转变为γ-C2S,稳定β-C2S;少量P2O5对C6A4MS的形成无抑制作用.

关键词: P2O5 , C6A4MS-C2S-C4AF系统 , β-C2S稳定

The sulfidation of a Cu-15 vol.% Nb alloy in H-2-H2S mixtures at 400-600 degrees C

Oxidation of Metals

The corrosion of a Cu-15 vol.% Nb alloy by H-2-H2S mixtures has been studied under 10(-12) atm S-2 at 400 and 500 degrees C and under 10(-10) atm S-2 at 500 and 600 degrees C. The alloy is a two-phase mixture of the two terminal solid solutions and is composed of a Cu-rich matrix containing particles of the Nb-rich phase elongated parallel to the sample surface and isolated mainly from each other. The alloy corroded at rates similar to those of pure copper at 400 and 500 degrees C under 10(-12) atm S-2, but more slowly than pure copper at 500 and 600 degrees C under 10(-10) atm S-2. The scales were duplex, containing an external layer of pure copper sulfide and an inner very porous region composed of a mixture of sulfides of the two metals in which, however, the core of the large Nb particles was still uncorroded.

关键词: niobium;copper;sulfidation;2-phase binary-alloys;high-temperature oxidation;low-oxygen pressures;most-reactive component;possible scaling modes;low oxidant pressures;1 atm o-2;h2-h2s mixtures;600-800-degrees-c;corrosion

C-S-H 凝胶及其研究方法

杨南如

硅酸盐通报 doi:10.3969/j.issn.1001-1625.2003.02.011

在分析C-S-H凝胶的复杂性和特征的基础上,就测定它的化学组成、C-S-H凝胶中[SiO4]4-四面体的聚合度及其结构的化学和物理的方法作了简要介绍.现代各种测试方法的出现和使用,对C-S-H凝胶的组成和集中[SiO4]4-四面体的聚合结构有了较为完整的概念.

关键词: C-S-H凝胶 , 化学组成 , 凝胶结构 , 测定方法

Q相-C2S-C4AF-C12A7系列水泥形成的研究

姜奉华 , 徐德龙

硅酸盐通报 doi:10.3969/j.issn.1001-1625.2004.06.006

通过研究Q相与C2S和Q相与C4AF的共存条件,构造Q相-C2S-C4AF水泥系统,对此系统水泥形成条件进行研究.研究表明:Q相与C2S和Q相与C4AF能够共存,可以组成Q相-C2S-C4AF-C12A7水泥系统.在Q相-C2S-C4AF-C12A7水泥系统中,Q相在1270℃开始生成,随着温度的升高,Q相的生成量逐渐增大;采用V2O5对β-C2S具有较好的稳定作用.随着C4AF量的增加,Q相的量也在增加,同时,烧成温度降低.

关键词: Q相 , Q相-C2S-C4AF水泥 , 形成条件 , 抗压强度