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Influence of Grain Size and Texture on the Yield Asymmetry of Mg-3Al-1Zn Alloy

S.M. Yin C.H. Wang Y.D. Diao S.D. Wu S.X. Li

材料科学技术(英文)

The yield asymmetry between compression and tension of magnesium alloy Mg-3Al-1Zn (AZ31) with different grain sizes and textures has been studied by tensile and compressive testing of as-cast, as-extruded and equal channel angular pressed (ECAPed) specimens. The significant yield asymmetry (the ratio of yield strength between compression and tension σycyt is~0.44) was found in as-extruded specimens and the corresponding microstructure evolution during deformation revealed that {1012} tensile twinning is the underlying reason for the large yield asymmetry. Strong texture and grain size are influential factors for large yield asymmetry. The separate contributions of grain size and texture on yield asymmetry were investigated.

关键词: Magnesium alloys

D2、M2、S5模具扁钢脱碳特性实验研究

赵德文 , 郭长武 , 刘相华 , 王国栋 , 徐辉 , 戴建明

钢铁

开展了在空气和氮气两种气氛下,采用Gleeble-1500热模拟机与普通电炉两种加热方式、不同加热温度、加热时间对D2、M2、S5钢脱碳层深度影响的试验研究。依据试验结果,结合现场实际制定了较为合理的生产工艺并在现场成功应用,使上述模具扁钢脱碳层指标达到了美国ASTM-A681技术标准。

关键词: 脱碳层深度 , 模具扁钢 , ASTM-A681

Corrosion of Y, Fe and Fe-15Y in H-2-H2S mixture under 10(-3) Pa S-2 at 600 similar to 800 degrees C

材料科学技术(英文)

The corrosion of an Fe-based alloy containing 15 wt pet Y in H-2-H2S mixtures under 10(-3) Pa S-2 was studied at 600 similar to 800 degrees C in an attempt to find materials with improved sulphidation resistance with respect to pure Fe. The presence of Y has been shown to be beneficial, but not sufficient to the level expected. In fact, the alloy is able to form at all tested temperatures an external FeS layer, beneath which a zone containing a mixture of the two sulphides is also present. Thus, Fe can still diffuse through this region to form the outer FeS layer with non-negligible rate. The corrosion rate of Fe is considerably reduced by the Y addition, but the alloy corrodes still much more rapidly than Y. The sulphidation kinetics is generally rather irregular for both the pure metals, while the corrosion rate of the alloy decreases with time and tends to become parabolic after an initial period of 12 similar to 17 h. The sulphidation behaviour of the alloys is discussed by taking into account the presence of an intermetallic compound Fe17Y2 and the limited solubility of Y in Fe.

关键词: high-temperature sulfidation;most-reactive component;ni-nb alloys;h2-h2s mixtures;behavior;600-degrees-c-800-degrees-c;oxidation

基于S3C44B0与S1D13506的多功能显示终端的设计与实现

张其阳 , 张澎

液晶与显示 doi:10.3969/j.issn.1007-2780.2009.06.019

设计实现了一种基于S3C44B0微处理器和S1D13506视频控制器的多功能显示终端,具有成本低、配置性高、应用范围广等特点.介绍了该终端的整体结构, 详细描述了各个组成模块的设计实现方法及涉及的相关技术,并给出了验证结果.

关键词: 显示终端 , S1D13506 , S3C44B0 , μC/OS , μC/GUI

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

S-D系统的统一模型与稀磁合金的电子比热

陈丽 , 韩福祥

低温物理学报 doi:10.3969/j.issn.1000-3258.2000.01.013

本文采用Anderson s-d混合模型和s-d交换模型,讨论了磁性杂质溶入金属后,对稀磁合金比热的影响,并对Cd-Mn合金进行了定量的讨论.

关键词:

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

铁基超导体Minimum模型中的d波和扩展s

车玮玮 , 苏希玉 , 王梅

低温物理学报

对比研究了Minimum模型中d-波配对和扩展s-波配对的基本性质.结果表明,超导序参量按类BCS关系随温度变化,重整化参数t对超导有抑制作用,当t足够大时,超导消失,系统进入正常金属相.此外,讨论了超导序参量随不同参量的变化关系.对于d波,系统有稳定态;而对于扩展s波,系统则没有稳定态.

关键词: Minimum模型 , d-波 , 扩展s-波 , 铁基超导体

Corrosion of Y, Fe and Fe-15Y in H_2-H_2S Mixture under 10~(-3) Pa S_2 at 600~800℃

Yan NIU , Weitao WU and Chaoliu ZENG (State Key Lab. for Corrosion and Protection , Institute of Corrosion and Protection of Metals , Chinese Academy of Sciences , Shenyang 110015 , China)F. Gesmundo and F. Viani (Instituto di Chimica , Facolta di Ingegneria , Un

材料科学技术(英文)

The corrosion of an Fe-based alloy containing 15 wt pct Y in H2-H2S mixtures under 10-3 Pa S2 was studied at 600~800℃ in an attempt to find materials with improved sulphidation resistance with respect to pure Fe. The presence of Y has been shown to be beneflcial, but not sufficient to the level expected. In fact, the alloy is able to form at all tested temperatures an external FeS layer, beneath which a zone containing a mixture of the two sulphides is also present. Thus,Fe can still diffuse through this region to form the outer FeS layer with non-negligible rate. The corrosion rate of Fe is considerably reduced by the Y addition. but the alloy corrodes still much more rapidly than Y. The sulphidation kinetics is generally rather irregular for both the pure metals, while the corrosion rate of the alloy decreases with time and tends to become parabolic after an initial period of 12~17 h. The sulphidation behaviour of the alloys is discussed by taking into account the presence of an intermetallic compound Fe17Y2 and the limited solubility of Y in Fe

关键词:

同位旋效应对F同位素s-d能级间隙的影响

郭艳青 , 任中洲

原子核物理评论

在单粒子势模型的框架下,计算了O同位素和F同位素的基态和某些低激发态的能级值、均方根半径值及密度分布.通过在伍兹-萨克逊势中引入同位旋依赖项,研究了同位旋效应对F同位素s-d能级间隙的影响.理论计算得到的均方根半径值和自旋宇称值与实验结果一致.尤其是,理论计算能够实现16F,15F和14F中2s1/2与1d5/2质子能级间的反转,且F同位素中s-d质子能级间隙及其整体变化趋势与已知实验结果符合较好.此外,理论结果表明12F的(1/2)+第一激发态为单质子晕态.

关键词: 同位旋效应 , 能级反转 , 质子晕

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