材料期刊网

Analysis of Temperature Dependence of Phases and Surface Morphology of Bi2Sr2Cax-1CuxOy Thin Films Using Reactive Co-Deposition Method

Z.H. Zou , X.M. Yu , B.S. Zhang , Y. Qi , null , null , null , null , null , null , null , null , null , null , null , null , null

金属学报(英文版)

A reactive co-deposition processing for obtaining high-quality single-phase Bi2Sr2Cax-1CuxOy (Bi2212) thin films has been investigated using molecular beam epitaxy (MBE) with 2.7 × 10-3Pa ozone gas introduction for oxidation. The thin films with a constant composition of almost 2 : 2 : 1 : 2 were designed to be fabricated at the substrate temperature between 675 and 780℃, the substrate temperature dependence of the surface morphology and the emergence phases were investigated in detail. A noticeable result is that the distribution of Cu element in the thin films is sensitively changed with the substrate temperature. At 750℃ it is inclined to locate in the periphery of each grain through the diffusion process. At 780℃ the Cu-compositional fluctuation brought around the dendritic crystal growth in the thin films. Below 705℃, the Bi2212 single-phase cannot be achieved in the thin films.

关键词: Bi2212 (Bi2Sr2Cax-1CuxOy) single-phase , null

Properties Of Mgb2 Films Fabricated On Copper Cathodes By Electrochemical Technique

H.Z. Yang , X.G. Sun , W.Q.Huang , M.L. Li , X.M. Yu , B.S.Zhang , Y.Qi , Q. Zhao

金属学报(英文版)

An electrochemical technique has been introduced and applied to fabricate superconducting MgB2 films in molten salts. MgCl2, Mg(BO2)2, NaCl, and KCl were used as electrolyte, graphite was used as the anode, and copper was used as the cathode, respectively. X-ray diffraction (XRD) analysis was chosen to investigate the phase composition and crystallinity of the films at different electrolysis temperatures. Standard four-probe technique and SQUID were applied to investigate the temperature dependence of resistance (R-T) properties and magnetic properties of the films, respectively. The results indicate that MgB2 films have been fabricated on the copper cathodes, and superconducting transition takes place close to 50 K.

关键词: MgB2 film , null , null

MAGNETIC PROPERTIES OF Nd_2(Fe_(1-x)M_x)_(14)B(M=C,Si)ALLOYS

XING Feng JIANG Chao HE Wenwang Department of Physics , Peking University , Beijing , China [Originally published in ACTA METALL SIN (CHINESEEDN) 24 (5) 1988pp B348—B352 , received 22 October 1986:in revised form 8 May 1987]

金属学报(英文版)

The magnetic properties of Nd_2(Fe_(1-x)M_x)_(14)B(M=C and Si) compounds have been investi- gated.Substituting Fe by small amount of metalloid C and Si atoms,the compounds are in tetragonal structure and have uniaxial anisotropy.The substitution of C for part of Fe de- creases the Curie temperature of the compounds and the intrinsic coercivity of bond samples at low temperature.The replacement of Fe by Si makes the Curie temperature increase with a maximum at the vicinity of x=0.15.When the range of the content of Si is 0≤x≤0.10,the coercivity distinctly increases at room temperature.from 62.7 kA/m at x=0 to 138.7kA/m at x=0.06,where the residual magnetization has a maximum:in the mean time the saturation magnetization decreases only by a small amount.

关键词: Nd-Fe-B alloy , null , null

Nd_2(Fe_(1-x)M_x)_(14)B(M=C,Si)合金的磁性

邢峰 , 江潮 , 何文望

金属学报

本文研究了Nd_2(Fe_(1-x)M_x)_(14)B的磁性。少量类金属原子C和Si取代部分Fe,能形成四方结构,且具有单轴各向异性。碳取代Fe,使化合物的Curie温度降低,低温下粘结体样品的内禀矫顽力减少;而Si对Fe的取代可使Curie温度升高,并在x=0.15附近达到极大值。含Si样品在0≤x≤0.10范围内,矫顽力显著增加,室温下从x=0的62.7kA/m增加到x=0.06的138.7 kA/m,并且在x=0.06附近,剩磁有一个极值,饱和磁化强度减少不多。

关键词: Nd-Fe-B合金 , magnetic properties , Curie temperature

MnP_(1-x)M_x系列合金的磁热效应

门德 , 松林 , 伊博乐 , 刘璟芳 , 伊日勒图 , 特古斯

稀有金属 doi:10.3969/j.issn.0258-7076.2010.01.027

研究了1:1型MnP基系列合金MnP_(1-x)M_x(M=Si,Sb,Ge,Zn,Sn)(x=0,0.1)的结构及其磁热效应.室温X射线衍射表明该系列合金的主相结构均为正交MnP结构,空间群为Pnma.在用Ce,Sb,Zn,Sn作为替代元素的合金中存在少量第二相Mn_(5.64) P_3.磁性测量表明该系列合金MnP_(1-x)M_x(M=Si,Sb,Ge,Zn,Sn)(x=0,0.1)的存在由铁磁-顺磁的二级相变.其居里温度T_c分别为286,295,291,295,295 K.通过磁化曲线计算了MnP_(1-x)M_x(M=Si,Sb,Ge,Zn,Sn)(x=0,0.1)合金的最大等温磁熵变-△S_m,均在0.7-1.3 J·kg~(-1)·K~(-1)之间.

关键词: 合金 , 磁制冷 , 磁热效应 , 磁熵变

M_1-M_2-x-y系优势区相图的绘制及其应用

王龙章 , 黄克雄 , 骆如铁 , 姚渝 , 叶大陆 , 陈新民

金属学报

本文讨论了双金属共存体系M_1-M_2-x-y,当两种金属的化合物相互作用生成多金属化合物时,优势区相图的绘制原理、方法及计算机程序。通过绘制Zn-Fe-SO系的优势区相图,分析了ZnO·Fe_2O_3的生成及稳定条件,并说明了其在硫化锌矿焙烧中的指导作用。

关键词: M_1-M_2-x-y体系 , predominance diagram , roasting , zinc sulfide ore

DRAWING PREDOMINANCE DIAGRAM OF M_1—M_2—x—y SYSTEM AND ITS APPLICATION

WANG Longzhang HUANG Kexiong LUO Rutie YAO Yu YE Dalu CHEN Xinmin Central South University of Technology , Changsha , China

金属学报(英文版)

Discussions were made of the principle,method and computer program for drawing the pre- dominance diagrams of the bi-metal co-existed system M_1-M_2-x-y in which the multi-me- tallic compounds may be produced by interaction between compounds of both metals.The formation of zinc ferrite and its stable region have been analyzed through drawing Zn-Fe-S-O system predominance diagrams.The availability of the diagram is given the di- rection to roast the zinc sulfide ore as well.

关键词: system M_1-M_2-x-y , null , null , null

Ab initio elastic stiffness of nano-laminate (MxM '(2-x))AlC (M and M ' = Ti, V and Cr) solid solution

Journal of Physics-Condensed Matter

We have investigated the elastic stiffness and electronic band structure of nanolaminate (MxM2-x')AIC solid solutions, where M and M' = Ti, V and Cr by means of the ab initio pseudopotential total energy method. The second-order elastic constants, bulk moduli and anisotropic Young's moduli are computed for the solid solutions, in which x is changed from 0 to 2 in steps of 0.5. The bulk moduli of (MxM2-x')AIC is found to be approximately the average of the two end M(2)AIC and M-2'AIC phases as the substitution content x, as well as the valence electron concentration (VEC), varies in the compounds. On the other hand, the shear modulus c(44), which by itself represents a pure shear shape change and has a direct relationship with hardness, saturates to a maximum as VEC is in the range 8.4-8.6. It implies that solid solution hardening may be operative for alloys having VEC values in this range. Furthermore, trends in the elastic stiffness are interpreted in terms of the electronic band structure. We show that monotonically incrementing the bulk moduli is attributed to the occupying states involving transition-metal d-Al p covalent bonding and metal-to-metal dd bonding. The maximum in c44, on the other hand, originates from completely filling the shear resistive transition-metal d-Al p bonding states. Most importantly, we predict a method to optimize the desired elastic stiffness by properly tuning the valence electron concentration of (MxM2-x')AIC ceramics.

关键词: behavior;phases

152Eu20+与Au作用产生M-X射线的动能阈值

梁昌慧 , 张小安 , 李耀宗

原子核物理评论 doi:10.11804/NuclPhysRev.30.01.063

测量了动能为2.0 MeV的高电荷态离子152Eu20+入射Au表面产生的Au的M((),Mα和M6特征X射线和Eu的Mα-X射线.对X射线产生的微观机制进行了初步分析,并通过半经典两体碰撞近似,估算了Eu20+与Au作用产生的Au的M-X射线和Eu的M-X射线的动能阈值.此结果对高电荷态离子与固体表面相互作用的动力学过程的研究以及在辐射能量转换效率研究中如何选取合适的弹靶组合具有重要的参考价值.

关键词: 高电荷态离子 , X射线 , 动能阈值

TMCP工艺对X100管线钢M/A岛的影响

齐亮 , 彭凯 , 周军 , 杨泰胜 , 张迎晖 , 汪志刚

材料导报 doi:10.11896/j.issn.1005-023X.2016.02.022

M/A岛是X100管线钢典型组织,对钢的强韧性有着重要的影响.利用热模拟和显微分析技术研究了冷却速度、变形量和等温温度对X100管线钢中M/A岛的影响规律.结果表明:随着冷速增加,M/A岛体积分数和平均尺寸都减小,由在晶界处分布的较大块状向板条间隙弥散分布的细小片层状转变;随着变形量增加,M/A岛体积分数先增加,变形量为40％达到最大,变形量达到50％时,M/A岛体积分数降低;快冷后随着等温温度升高,M/A岛平均尺寸增大,等温温度为450℃时体积分数最大,温度继续升高体积分数减小.观察到M/A岛形貌多呈棱角状、链条状、片条状和针状,分布在晶界和基体内,岛内精细结构观察到微孪晶马氏体.

关键词: 管线钢 , 粒状贝氏体 , 马奥岛 , 显微结构 , 冷却速度