材料期刊网

STUDY ON CONSTITUTIVE RELATIONSHIP OF Ti-5Al-2Sn-2Zr-4Cr-4Mo ALLOY AND SIMULATION OF HOT FORMING PROCESSES

X. Q. Zhang , Y. H. Peng , M. Q. Li and X. Y. Ruan( 1)Department of Plasticity Technology , Shanghai Jiao TOng University , Shanghai 200030 2)School of Material Science and Engineering , Northwestern Polytechnical University , Xi' an 710072 , China)

金属学报(英文版)

In the present research, artificial artificial networks hare be applied to establish the constitutive rela- tionship model of Ti - 5Al - 2Sn - 2Zr - 4Mo - 4Cr (wt - % ) alloy. In the first stage of the re- search, an isothermal compressive experiment using Thermecmastor - Z hot simulator is studied to ac- quire the flow stress at different deformation temperature,equivalent strain and equivalent strain rate. Then,a feed - forward neural network is trained by using the experimental data.After the training process is finished, the neural networks become a knowledge-based constitutive relationship system. Comparison of the predicted and experimental results results shows that the neural network model has good le- arning precision and good generalization.The neural neural network methods are found to show much better agreement than existing methods with the experiment data, and have the advantage of being able to deal with noisy for or data with strong non - linear reationships. At last, this model can be aused to simulate the flow behavior of Ti - 5Al - 2Sn - 2Zr - 4Mo - 4Ca alloy.

关键词: titanium alloy , null , null , null

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

Li1+x(Fey/2Niy/2Mn1-y)1-xO2正极材料的合成及电化学性能

王秋艳 , 徐连义 , 付煜 , 张艳丽 , 谢嫚

稀有金属材料与工程

采用低温共沉淀-水热-煅烧法合成了锂离子电池Fe-Ni-Mn体系正极材料Li1+x(Fey/2Niy/2Mn1-y)1-xO2,并用XRD、SEM、ICP光谱和电化学性能测试对材料进行了表征.XRD测试和ICP分析表明,Fe、Ni取代Li2MnO3中的部分Mn,形成很好的固溶结构yLiFe1/2Ni1/2O2-(1-y)Li2MnO3 (y=0.l,0.2,0.3,0.4,0.5).SEM测试表明,取代量y不同,材料的表观形貌有所不同,y=0.4时材料的颗粒粒径均匀、较小,呈类球形结构.电化学性能测试表明,当y=0.4时,循环稳定性最好,充放电50次后放电比容量仍可维持在195.0 mAh/g,放电中值电压为3.5 V,y=0.4时样品在大倍率放电下的电化学性能表现良好.

关键词: 锂离子电池 , 正极材料 , Li1+x(Fey/2Niy/2Mn1-y)1-xO2 , 离子掺杂

Li1+xV3-yMyO8(M=Mo,P)高温阴极放电性能的研究

曹笃盟 , 李志友 , 周科朝

稀有金属材料与工程

采用固相反应法制备了Li1+xV3-yMyO8(M=Mo,P;0≤y≤0.4),研究了不同Mo和P含量对Li1+xV3O8相的影响,并首次对其进行了高温阴极放电性能的研究.结果表明:Mo和P掺杂量分别为y≤0.2和y＜0.2时可获得纯Li1+xV3O8相;Mo掺杂使Li1+xV3O8峰值电压提高0.3 V,比容量提高25%,嵌入的Li+量最高可达x=3.8;P掺杂(y≤0.20)对Li1+xV3O8的峰值电压和比容量影响较小.化学嵌锂实验也证实掺杂后的材料具有更快的Li+嵌入速度.

关键词: Li1+xV3O8 , 热电池 , 掺杂 , 比容量

Improving plasticity and toughness of Cu-Zr-Y-Al bulk metallic glasses via compositional tuning towards the CuZr

Journal of Materials Research

In this work, we propose a simple approach for designing plastic bulk metallic glasses (BMGs) by exploiting the ductility of intermetallic compounds involved in the BMG-forming system. Its validity was examined by investigating a series of quaternary CuZr-Y-Al alloys along the composition tie-line between Cu(42)Zr(44.4)Y(3.6)Al(10) (Y1) and the B2 CuZr phase, expressed as (Cu(0.5)Zr(0.5))(x)(M)(100-x) (M = Zr(0.15)Y(0.225)Al(0.625), 84 <= x <= 93). When tuning the composition towards the CuZr, the glass-forming ability of alloys is dramatically degraded, showing a reduction of critical diameter D(c) for BMG formation from 16 mm at x = 84 (Y1) to 2 mm at x = 93. As the composition of BMGs shifts to the CuZr terminal, the shear modulus mu of the BMGs decreases, whereas the Poisson's ratio nu increases. With respect to the Y1 BMG, compressive plasticity and toughness of the Y2 BMG (x = 92, D(c) = 4 mm) with a higher concentration of the CuZr are improved, which is consistent with its lower mu and higher nu values.

关键词: intermetallic compounds;forming ability;alloys;compression;brittleness;ductility;density;system;range;flow

Multiferroic phase diagram of Y partially substituted Dy(1-x)Y(x)MnO(3)

Applied Physics Letters

The effect of nonmagnetic Y partial substitution at the Dy site in Dy(1-x)Y(x)MnO(3) up to x=0.2 on magnetism, specific heat, and ferroelectricity is investigated, which resulted in a preliminary multiferroic phase diagram. It is revealed that the Y partial substitution suppresses the Dy-spin ordering point (T(Dy)) and ferroelectric ordering point (T(FE)) but enhances the Mn-spin ordering point (T(N)). The interaction between the spins of Dy and Mn is remarkably affected by Y substitution. The measured electrical polarization depends on the Y substitution in a complex way because the ferroelectricity is sensitive to the interaction between the spins of Dy and Mn. (c) 2011 American Institute of Physics. [doi: 10.1063/1.3536506]

关键词: ferroelectricity;polarization

锂快离子导体Li1+2x+2yAlxMgyTi2-x-ySixP3-xO12系统的研究

张玉荣 , 王文继

功能材料

以LiTi2(PO4)3为基以天然高岭石为起始原料,经高温固相反应(～900℃)制得了一系列新的锂快离子导体材料Li1+2x+ 2yAlxMgyTi2-x-ySixP3-xO1 2(以下简称Ti-Mg-Lisicon).系统的合成温度随x和y值的增大而降低.应用交流阻抗技术测定的电导率数据结果表明x=0.1,y=0.1的合成物的室温电导率最好为1.01×10-4S/cm,而400℃时x=0.1,y=0.3的合成物的电导率最大,为2.53×10-2S/cm.XRD分析结果表明在x=0.1,y≤0.8;x=0.2,y≤0.6的组成范围内均能得到空间群为R3c的合成物.

关键词: 锂快离子导体 , Ti-Mg-Lisicon , 高岭石

Tunable magnetocaloric effect around hydrogen liquefaction temperature in Tb(1-x)Y(x)CoC(2) compounds

Physica B-Condensed Matter

The magnetic properties and magnetocaloric effect of Tb(1-x)Y(x)CoC(2) (x = 0, 0.1, 0.2, 0.3, 0.4) compounds have been investigated systematically. All the compounds undergo second-order transitions from paramagnetic to ferromagnetic states without thermal and magnetic hysteresis. With increasing Y content from 0 to 0.4, the Curie temperatures decrease nearly linearly from 28 to 18 K. The nature of the second-order phase transitions can be confirmed by Arrott plots. For Tb(0.6)Y(0.4)CoC(2) compound, the maximum value of the magnetic entropy change -Delta S(M) at 20 K is 9.35 J kg(-1) K(-1) for an external field change of 5T (5.14 J kg(-1) K(-1) for 2T). The large reversible magnetic entropy change makes Tb(0.6)Y(04)CoC(2) compound an attractive candidate for the application at hydrogen liquefaction temperature. (C) 2010 Elsevier B.V. All rights reserved.

关键词: Curie temperature;Magnetocaloric effect;Magnetic properties;ac susceptibility

INTERNAL OXIDATION BEHAVIOR OF Pd-40Ag-1M(M=Zr,Y)ALLOYS

NING Yuantao LI Yongnian Kunming Institute of Precious Metals , Kunmmg , China Professor , Kunming Institute of Precious Metals , Kunming , Yunnan , China

金属学报(英文版)

The internal oxidation behavior of Pd-40Ag-1M(M=Zr,Y)alloy wires has been studied in air at 800—1200℃.The relationship between the internal oxidation depth ξ and the reaction time t can be expressed as ξ= Kt~n,where n=0.5—0.75.The higher the temperature,the larger the value of n is.The active elements Zr and Y show different internal oxidation characters.For the alloys eontaining Zr,the oxidation rate along the grain boundaries is about twice as high as that in grains,and“lateral oxidation”exists along the grain boundaries.For the alloys containing Y,the oxidation rates in grains and along the grain boundaries are roughly the same,and there is no“lateral oxidation”along the grain bounda- ries.The activation energies of both alloys are in the range of 120—150kJ/mol.Some prop- erties for oxidized alloys were studied.The mechanisms of the internal oxidation were dis- cussed.

关键词: Pd-40Ag alloy , null , null , null , null