材料期刊网

EVOLUTION OF CREEP-FATIGUE DAMAGE IN TYPE 304 STAINLESS STEEL AND ITS DETECTION BY ELECTRICAL POTENTIAL METHOD

N. Tada , T. Kitamura , R. Ohtani and E. Nakayama (Department of Engineering Physics and Mechanics , Graduate School of Engineering , Kyoto University , Yoshida-hommachi , Sakyo-ku , Kyoto , 606-8501 , Japan)

金属学报(英文版)

Creep-fatigue test was carried out using smooth round bar specimens of Type 304 stainless steel. Cavities and small cracks on the cross-section of the specimen were carefully observed by a scanning laser microscope. Moreover, direct current electrical potential method (DC-EPM) was applied in order to evaluate non-destructively the distribution of internal cracks. The distribution evaluated by DC-EPM agreed well with the actual one.

关键词: creep-fatigue , null , null , null , null

Molten Salt Synthesis of Magnesium Aluminate (MgAl(2)O(4)) Spinel on Ti(3)AlC(2) Substrate

Journal of the American Ceramic Society

A MgAl(2)O(4) (MA) spinel layer was synthesized on Ti(3)AlC(2) substrate through the molten salt synthesis (MSS) method. The Ti(3)AlC(2) substrate was immersed in MgCl(2)center dot 6H(2)O powders and treated at 8001, 8501, and 900 degrees C for 4 h in air. A continuous and 10-mu m-thick MgAl(2)O(4) layer was obtained at 900 degrees C, by which the surface hardness of Ti(3)AlC(2) can be effectively improved. The combined scanning electron microscopy observations and crystal morphology simulation further revealed that the as-formed MgAl(2)O(4) presents tetragonal bipyramids morphology with (400)-orientation.

关键词: liquid reaction synthesis;oxide scale;ti3sic2;microstructure;precursors;resistance;diffusion;platelet;adhesion;behavior

橙红色荧光粉Ca10Li(PO4)7∶Sm3+的合成及其发光特性研究

滕晓云 , 白琼宇 , 边亚燕 , 杨保柱 , 段平光 , 李婷 , 徐书超 , 王志军 , 李盼来

人工晶体学报

采用固相法合成了Ca10Li(PO4)7∶xSm3+橙红色荧光粉,研究了材料的发光性质.结果表明,以404 nm近紫外光作为激发源时,Ca10Li(PO4)7∶xSm3+表现为多峰特征,主峰位于569 nm、606 nm、651 nm和713 nm,分别对应Sm3+的4G5/2→6H5/2、4G5/2→6H7/2,4 G5/2 →6H9/2 and 4 G5/2 →6H11/2跃迁发射,且606 nm发射峰最强,材料发射橙红光;监测606 nm发射峰,对应的激发光谱包含363 nm、376 nm、404 nm和478nm多个激发峰;改变Sm3+的掺杂量,发现Ca10 Li(PO4)7∶Sm3+的发射强度表现出先增大、后减小的变化趋势,x=0.05时发射强度最大,即存在浓度猝灭现象,造成浓度猝灭的机理为电多极相互作用,Ca10Li(PO4)7∶Sm3+的色坐标基本不变,位于橙红色区域.Ca10Li(PO4)7∶Sm3+具有较好的温度特性,激活能为0.188 eV.

关键词: 发光 , Ca10Li(PQ4)7∶Sm3+ , 固相法 , 荧光粉

纯铜表面等离子喷焊Ni60涂层组织及性能的研究

柯德庆 , 潘应君 , 童向阳

表面技术

采用等离子喷焊工艺在纯铜基体表面成功制备了Ni60焊层,并对其微观形貌、元素成分、显微硬度及耐磨性能进行分析.分析表明:焊层与基体呈现良好的冶金结合,稀释率仅为5％左右,且其显微组织呈细小枝晶状,硬质相呈弥散分布,焊层显微硬度高达606HV,耐磨性能较Cu-Ni合金焊层提高了1倍.

关键词: 等离子喷焊 , 纯铜 , 稀释率 , 耐磨性能

方块形Gd2O3∶Sm纳米发光粉体制备及发光性质研究

付晓燕 , 施刚 , 黄桂美 , 许龙山 , 张洪武

稀土

采用KOH-水热的方法制备出方块形纳米级Gd2O3∶Sm,并测定了它的光谱,研究了焙烧温度对发光强度的影响,结果表明,热处理对颗粒的形状影响较小,甚至800℃焙烧仍然能得到尺寸在50nm～100 nm的纳米方块.样品在569 nm、574 nm、584 nm,598 nm、606 nm、615 nm、621 nm,655 nm、668 nm处有发射峰,分别归属于4G5/2—6H5/2,4G5/2—6H7/2,4G5/2-6H9/2；其中,位于606 nm处4G5/2—6H7/2跃迁最强,样品发射出明亮的橙色光,400℃焙烧得到的样品其发光强度明显弱于800℃焙烧得到的样品.

关键词: 稀土发光材料 , 纳米方块 , Gd2O3∶ Sm

纳米金属陶瓷Ni-AIN复合层的超声-电沉积制备

吴蒙华 , 李智 , 夏法锋 , 傅欣欣

材料科学与工艺 doi:10.3969/j.issn.1005-0299.2005.05.028

采用超声-电沉积方法制备纳米金属陶瓷Ni-AlN复合层.研究了超声波机械扰动效用对电解液传质过程的作用,超声波空化效应对纳米粒子团聚的抑制作用,脉冲电参数对控制晶粒成核及生长的作用.采用优选工艺参数,在常用金属表面获得了由镍晶(20～60nm)和纳米粒子AlN构成的纳米级Ni-AlN复合镀层.镀层与基体结合比较牢固,结合力达到89 N,厚度11～12μm,平均表面硬度达到HV606.

关键词: 纳米金属陶瓷 , Ni-AlN复合层 , 超声波 , 脉冲电沉积 , 复合作用

DYNAMIC TENSILE BEHAVIOR OF 5CrMnMo AT ELEVATED TEMPERATURES

W.Huang , X.Nie , X.Zan , Y.M.Xia

金属学报(英文版)

A new experimental technique has been developed for the performance of high temperature, high-strain rate tensile experiments in the self-designed tensile impact apparatus. This technique uses rapid contact heating method to heat the specimen to the desired temperature, thus avoids a significant temperature rise in incident and transmitted bars, and at the same time it is capable of retaining a nearly homogeneous temperature field within the specimen. As an illustration of its application, the hightemperature response of the forging die steel 5CrMnMo at high strain rates has been examined. Stress-strain curves are obtained for this material at strain rates ranging from 230s^-1 to 1200s^-1 and at temperature ranging from 25 to 606PC, respectively. For comparison, quasi-static experiments are performed over a slightly smaller range of temperatures.

关键词: elevated temperature , null , null

(La1-xREx)0.9Sb0.1MnO3(RE=Nd,Ce,Pr,Tb)的磁性质研究

张丽 , 刘建 , 张桂荣

稀土

实验采用固相反应法制备了一系列钙钛矿锰氧化物(La1-xREx)0.9Sb0.1MnO3(RE=Nd,Ce,Pr,Tb).通过X射线衍射(XRD)分析,样品形成单相,为正交结构,空间群为Pbnm.样品的红外吸收光谱在599 cm-1～606cm-1范围内.M-T曲线结果表明,随着A位掺杂的稀土离子半径的逐渐减小,样品的居里温度逐渐降低.对样品的MR-H曲线结果分析,在室温300K、1.5T磁场下,RE离子半径及磁矩对样品的磁性质都有影响.

关键词: 磁性质 , 晶体结构 , 稀土 , 掺杂

ALTERNATIVE DESCRIPTION OF THE SHEAR PLANE OF THE R-PHASE

Q.B. Yang and J.A. Wert (Dept. of Physics , Xiangtan University , Xiangtan 411105 , China)(Dept. of Materials Science & Engineering , University of Virginia , Charlottesville , VA 22903-4402 , USA)

金属学报(英文版)

A high density of {110} shear planes has been observed in the R-phase (Al5CuLi3)following phase transformation from the AlCuLi icosahedral Phase. The Present paper shows that the atomic arrangement in the vicinity of the shear planes can be described as a two-dimensional periodic array of atom clusters with 5-fold symmetry. This result is obtained by projecting along the [1. 618...01] direction of the atomic positions from four adjacent lattice planes that cross the shear plane. The projection reveals that the shear plane consists of pentagonal arrangements of double triacontahedra,each pentagon incorporating 606 atoms. The calculated diffraction pattern from the pentagon has approximate 10-fold symmetry characteristic of a quasicrystal.

关键词: : shear plane , null , null

含有柠檬酸配体的钼硫配合物的合成、光谱及电子结构

邢永恒 , 徐吉庆 , 郭纯孝 , 白凤英 , 杨光第 , 邢艳 , 林永华 , 贾恒庆

应用化学 doi:10.3969/j.issn.1000-0518.2004.12.024

报道了Mo/S柠檬酸配合物的合成及结构,并用元素分析、红外光谱、紫外可见光谱、顺磁共振、核磁、热重-差热分析等手段进行了表征,用EHMO方法研究了配合物的电子结构. 将羧基的键序与该配合物的羧基红外振动峰相关联,即羧基的键序(0.914、0.869和0.809)对应该配合物羧基 CO 的振动峰劈裂为三重峰(1 606、1 587和1 550 cm-1);解释了该配合物的羧基红外振动峰是一宽峰且有劈裂的特点.

关键词: 钼硫化合物 , 柠檬酸 , 性质 , 电子结构