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Thermodynamic Analysis of Ag_3Ge Phase Formation

O.P.Pandey(School of Basic and Applied Sciences , Thapar Institute of Engineering and Technology Patiala-147 001 , India )S.N.Ojha and S.Lele(Dept. of Metallurgical Engineering , Banaras Hindu University , Varanasi-221 005 , India)

材料科学技术（英）

In the present work a thermodynamic model is presented for the nucleation of metastable Ag3Ge phase from the undercooled melt in Ag-Ge alloy system. It is shown that under kinetically induced favourable condition, nucleation of a single phase compound with an approximate stoichiometry Ag3Ge has greater affinity for nucleation over Ag and Ge based phases requiring diffusion in the liquid.

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Shear response of the Sigma 9 < 110 > {221} symmetric tilt grain boundary in fcc metals studied by atomistic simulation methods

Physical Review B

The shear response of the Sigma 9 < 110 > {221} symmetric tilt grain boundary (GB) in three fcc metals Cu, Al, and Ni has been studied by atomistic simulation methods with the embedded atom method for interatomic potentials and with a bicrystal model. By applying an energy minimization procedure, it was found that there are two optimized structures of this particular GB at zero temperature for all the three metals studied. Shear of bicrystals at room temperature has been studied by the molecular-dynamics simulation method. Various kinds of structure evolution behavior have been found for this GB depending on the shear direction: (1) pure GB sliding; (2) GB atomic shuffling accompanied by lattice dislocation emission from the GB; and (3) GB migration coupled with GB sliding, namely, GB coupling motion. The GB coupling motions can differ in the direction and distance of the GB migration depending on the shear direction. An analysis with the aid of the coincidence site lattice theory indicates that the structure evolution behavior can be attributed to several elementary structure transformations inherent to this particular GB. A pair parameter (lambda, kappa) is proposed to describe the GB coupling motions.

关键词: sliding resistance;molecular-dynamics;cubic-crystals;misorientation;dependence;dislocations;copper;nanocrystalline;deformation;aluminum;stress

The effect of crystallographic orientation on the oxidation behavior of a single-crystal nickel-base superalloy

Oxidation of Metals

The oxidation kinetics of DD100 nickel- base single- crystal alloy, with ( 221) and ( 100) surface orientations were tested in this study by thermogravimetry. A pronounced anisotropy in both the cyclic and isothermal oxidation resistance of DD100 alloy was observed. The ( 221) crystallographic surface of DD100 had a slower oxidation rate than the ( 100) surface when isothermally exposed to stationary air at 950degreesC, whereas the opposite results were obtained at 1050degreesC. When cyclically oxidized at 1100degreesC, the weight loss of samples with ( 221) surfaces was significantly greater than that of ( 100) surfaces, so that the cyclic- oxidation anisotropy was more remarkable at 1100degreesC than at 950degreesC. The different spatial alignment of the gamma' / gamma interface is thought to be responsible for the anisotropic oxidation behavior of the nickel- base single crystal alloy.

关键词: single-crystal nickel-base superalloy;high-temperature oxidation;oxidation kinetics;oxidation anisotropy;epitaxially induced strains;internal nitridation;oxide films;cu2o;films;growth;copper;creep;faces;sulfur

异步累积叠轧超细孪晶铜织构取向的演变

周蕾 , 史庆南 , 蔡晓兰 , 王军丽

材料热处理学报

孪晶能够在保持铜材电导率基本不变的情况下提高铜材强度,异步叠轧制备出超细晶铜材,再结晶过程中形成大量超细孪晶,通过背散射电子衍射研究织构演变,异步叠轧变形后原料铜板中的退火孪晶织构组分{ 114} 〈221〉消失,形成大量剪切织构{001}＜〈110〉和铜型织构{112}＜〈111〉＞组分,再结晶退火过程中,逐渐形成新的织构组分:{113}＜〈141〉＞、{125}＜〈112〉＞、{221} 〈114〉,通过矩阵计算得出,其中{221}＜〈114〉＞组分实质上是异步叠轧形成的剪切织构再结晶退火时沿{111}面的镜面反映,而形成的孪晶取向.

关键词: 异步叠轧 , 铜 , 超细孪晶 , 织构

轧制方向对Ni47Ti44Nb9锻造板,热轧板及冷轧板织构影响

冯昭伟 , 米绪军 , 王江波 , 袁志山 , 缪卫东 , 周瑾

稀有金属材料与工程

采用XRD研究了Ni47Ti44Nb9锻造板坯织构、不同热轧、冷轧方向板材织构.研究表明,锻造板坯有典型的γ取向线织构,锻板心部最强取向在{111}<112>.沿轧向(RD)、交叉方向(CD)、横向(TD)热轧板织构类型相似,主要有3条取向线织构,接近{ll4}、{223}、{332}(或{221}),{332}面织构取向密度最强,最强织构分别为{221}<110>、{332}<113>、{332}<023>,不出现γ-织构.沿与轧向成0°、45°、90°方向二次冷轧最强织构近似为{332}<110>.90°方向二次冷轧织构强度最高,有多个强织构组分,γ-织构得到显著加强.

关键词: Ni47Ti44Nb9形状记忆合金 , 织构 , 轧制方向 , 热轧板 , 冷轧板

一种微乳酸体系的实验室研究

陈馥 , 李茜璐 , 艾加伟 , 陈红均 , 魏云锦

应用化学 doi:10.3724/SP.J.1095.2011.00607

为降低酸化过程中酸液对油管和套管的腐蚀,增加酸液对地层的穿透距离,通过阳-非离子表面活性剂复配,成功制备了单相微乳土酸体系.并得出了较优的实验室配方(质量分数):A-126 2.5％,CHJ-102.5％,正丁醇1.2％,正辛醇2.3％,W-221 0.5％,土酸67.0％,柴油24.0％.通过添加适量的阴离子表面活性剂W-221,使体系在81℃保持了良好的热稳定性.在室温和70℃下分别与P110S钢片反应,与同浓度的土酸相比,缓蚀率达到90.57％.在70℃下与人造砂岩岩芯反应,溶蚀率降低到了0.5％.

关键词: 微乳酸 , 表面活性剂 , 缓蚀 , 耐温

3英寸双面YBCO高温超导外延薄膜研究

陈家俊 , 陶伯万 , 邓新武 , 刘兴钊 , 李德红 , 张鹰 , 何世明 , 李言荣 , 羊恺 , 张其劭

低温物理学报 doi:10.3969/j.issn.1000-3258.2003.z1.004

本文采用倒筒直流溅射方法(ICS)结合基片变速双轴旋转方式原位生长Φ3英寸双面YBCO高温超导外延薄膜.膜厚分布最大偏差小于10%,薄膜样品的中心与边缘部分的Tc0均达到90K,ΔTc≤0.3K,FWHM(005)≈0.2°,Rs(10GHz,77K)≈0.8mΩ,Jc值分布在2.2～3.1MA*cm-2之间,表明样品均匀性良好.

关键词: 高温超导薄膜 , YBCO , 均匀性

X射线荧光法分析钢中的稀土总量

齐郁 , 李小杰 , 崔隽 , 沈克 , 葛宜运

冶金分析 doi:10.3969/j.issn.1000-7571.2002.06.008

对如何采用X射线荧光仪检测钢中的各主要稀土元素,然后再计算出稀土总量的方法进行了研究.通过对分析条件、最佳计数时间、试样研磨深度等项目进行探讨,建立了一套快速分析钢中稀土总量的方法.实践证明,该方法可快速、准确地检测出含量.005%以上的稀土总量,完全可以满足生产的需要.

关键词: X射线荧光法 , 钢 , 稀土

Behaviour of Rare Earths in Low Sulphur Steel

Qin LIN+ , Aisheng LIU , Wen YE , Zongsen YU , Dept. of Physical Chemistry , University of Science and Technology Beijing , Beijing , 100083 , China

材料科学技术（英）

In steels 16Mn and X60 with low S content (0. 003～0. 005%), rare earth metals (REM) still show ef- fects on purifying the molten steel and controlling the sulphide morphology. The optimum ratio of RE/S is about 2. 0, which causes lower content of oxygen and inclusions and higher impact toughness. The amount of REM in solid solution in the steel was determined by means of inductive coupling plasma (ICP) spectroscopy. The dissolved REM in low S steel could decrease the propor- tion of pearlite and increase the strength of the steel.

关键词: rare earths , null , null