材料期刊网

STUDY ON STRENGTHENING AVIATION ALUMINIUM ALLOY BY LASER SHOCK PROCESSING

Q.L.Deng1) , W.D.Huang1) , Y.H.Zhou1) , C.Y.Yu2) , Y.K.Zhang2) , Y.X.Tang2) and H.Zhang2) 1) State Key Lab .of Solidification Processing , Northwestern Polytechnical University , Xi’an 710072 , China 2) Mechanical Department , Nanjing University of Aeronautics & Astronautics , Nanjing 210016 , China

金属学报(英文版)

The mechanism oflasershock processing wasanalyzedinthispaper. Westudyexperimentallythelasershock processingon 2024 T62 aviation aluminium alloys. Theexperimental results show thefatiguelife of 2024 T62 aviation aluminium alloysshocked by a laserisimprovedgreatly.

关键词: lasershock processing , null , null

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

La2O3-B4C系反应合成LaB6粉末

郑树起 , 闵光辉 , 邹增大 , 王效志 , 韩建德

金属学报

系统研究了利用La2O3和B4C粉制备LaB6粉末的反应合成工艺.La2O3-B4C系反应热力学分析表明反应产物的气体分压对LaB6的形成有重要影响,减小气体分压可以明显降低LaB6的合成温度,结合DTA测定结果,确定了LaB6粉末的合成温度.利用X射线衍射分析了不同温度和保温时间条件下所生成粉末的相组成,并分别用扫描电镜和化学分析方法分析了所生成LaB6粉末的颗粒尺寸、形貌及纯度.实验结果表明,La2O3-B4C系制备LaB6粉末的优化工艺是真空度133 Pa,1673 K保温2.5 h,所合成的LaB6粉末颗粒比较规整,大多呈近似圆球形,平均直径3μm,纯度达98.2%.

关键词: La2O3 , null , null , null , null

La2O3-B4C系反应合成LaB6粉末

郑树起 , 闵光辉 , 邹增大 , 王效志 , 韩建德

金属学报 doi:10.3321/j.issn:0412-1961.2001.04.018

系统研究了利用La2O3和B4C粉制备LaB6粉末的反应合成工艺.La2O3-B4C系反应热力学分析表明反应产物的气体分压对LaB6的形成有重要影响,减小气体分压可以明显降低LaB6的合成温度,结合DTA测定结果,确定了LaB6粉末的合成温度.利用X射线衍射分析了不同温度和保温时间条件下所生成粉末的相组成,并分别用扫描电镜和化学分析方法分析了所生成LaB6粉末的颗粒尺寸、形貌及纯度.实验结果表明,La2O3-B4C系制备LaB6粉末的优化工艺是真空度133 Pa,1673 K保温2.5 h,所合成的LaB6粉末颗粒比较规整,大多呈近似圆球形,平均直径3μm,纯度达98.2%.

关键词: La2O3 , B4C , 反应 , 合成 , LaB6

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

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

Mg-2Y-xZn(x=1,2,3at％)合金的显微组织与力学性能

刘欢 , 薛烽 , 白晶 , 周健 , 孙扬善

稀有金属材料与工程

研究了Mg-2Y-xZn(x=1,2,3 at％)合金在铸态、退火态和挤压态的显微组织与力学性能.结果表明:随着合金中Zn含量的增加,合金显微组织中第二相依次为18R-LPSO相、(LPSO+ W)混合物和W相.在退火过程中,层片状的14H-LPSO结构析出并沿块状18R-LPSO结构向基体中生长,W相由铸态时弯曲的条纹状转变为颗粒状.经过挤压变形后,LPSO结构和W相均沿挤压方向排列,合金性能得到大幅度提高,其中Mg-2Y-1Zn合金具有最好的室温力学性能,抗拉强度为320 MPa,延伸率达到11.2％.

关键词: 镁合金 , 钇 , 长周期堆垛有序结构 , 挤压 , 拉伸性能

Solidification of nitrogen-atomized Al(86)Ni(6)Y(4.5)Co(2)La(1.5) metallic glass

Journal of Materials Research

A comprehensive investigation has been made of the solidification of nitrogen-atomized Al(86)Ni(6)Y(4.5)Co(2)La(1.5), using focused ion beam, transmission electron microscopy, and other analytical means. Face-centered cubic Al(2)Y was identified to be the leading crystalline phase rather than crystalline Al. A new orthorhombic-structured phase was identified in partially or fully crystallized powder particles. Apart from oxygen, nitrogen was also found to be associated with the leading crystalline phase Al(2)Y in which nitrogen exists as substitutional N(x-). These findings facilitate the basis for understanding the unique aspects of the Al(86)Ni(6)Y(4.5)Co(2)La(1.5) bulk metallic glass, including its powder preparation by gas atomization.

关键词: forming ability;gas-atomization;homogeneous structures;alloys;nucleation;yttrium;systems;powders;ti;microstructure

间隙碳原子对(Er_(1-x)Sm_x)_2Fe_(17)C_y化合物形成、结构与磁性的影响

沈保根 , 孔麟书 , 曹蕾 , 王芳卫 , 詹文山 , 郭慧群 , 赵见高

金属学报

用快淬方法制备了单相(Er_(1-x)Sm_x)_2Fe_(17)C_y(x=0.2,<3.0;x=0.5,y<2.0)化合物,研究了它们的形成、结构、稳定性及内禀磁性结果表明,它们在高温是稳定的,随碳含量的增加,晶体结构由六角的Th_2Ni_(17)型向菱方的Th_2Zn_(17)型转变间隙碳原子的引入导致了单胞体积的膨胀、室温饱和磁化强度和Curie温度的增加当y>1.0时,(Er_(1-x)Sm_x)_2Fe_(17)C_y样品在室温均显示出单轴各向异性

关键词: (Er(1-x)Sm_x)_2Fe_(17)C_y间隙碳化物 , interstitial carbides , magnetic properties