M.D. Starostenkov
,
E. V.Kozlov
,
O. V. Andruhova
,
N. V. Lomskikh
,
N.M. Gurova and A. V. Borissov 1) General Physics Department
,
ASTU
,
Lenin St. 46
,
Barnaul
,
656099
,
Russia 2) Physics Department
,
TSABU
,
Solyanaya Sq.
,
2
,
Tomsk
,
634003
,
Russia
金属学报(英文版)
The kinetics of internal boundaries relaxation: antiphase domain boundaries and interphase boundaries-in the conditions of high-temperature annealing and the structure transformations are investigated in homophase and heterophase systems. Homophase systems look like ordered binary alloy and include antiphase domain boundaries of various orientation. Clear components border on ordered alloy in heterophase systems and two processes take place simultaneously here-disordering of binary alloy and solution in ordered phase of clear component. Computer experiment is realized in the sphere of temperatures close to the temperature of order-disorder phase transition in the limits of two-dimensional model of atom diffusion at the vacant knots of crystal lattics.
关键词:
computer simulation
,
null
,
null
,
null
,
null
Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing
Low-cycle fatigue (LCF) behavior of nickel-based precipitation-strengthened superalloy GH4145/SQ was investigated systematically under fully reversed total strain amplitude control conditions at 538degreesC in laboratory air. It was shown that the alloy exhibited a pronounced initial fatigue hardening followed by continuous fatigue softening to failure at high strain amplitudes, while at low strain amplitudes the initial hardening was followed by a well-defined saturation stage. Microstructure observations using optical and transmission-electron microscopy revealed that slip band density increased with increasing total strain amplitudes and the size of the y' precipitates tended to reduction due to repeated shearing by the dislocations with continuous cyclic straining. The above changes in microstructures during cycling were essentially responsible for the fatigue hardening-softening behavior of the alloy. Both optical and SEM micrographs indicated that at low strain amplitudes crack propagation was basically transgranular, while at high strain amplitudes crack propagation was essentially intergranular. Bilinear behavior with a change of slope at a plastic strain amplitude of about 0.2 pct was observed in cyclic stress-strain (CSS), Coffin-Manson (C-M) and plastic strain energy-life plots. A change in the number of operating slip systems and the fracture modes with the strain amplitude employed was used to explain this two-slope characteristic. In both the companion specimens test (CST) and the incremental step test (IST) methods the alloy exhibited non-masing type behavior. It was suggested that, for the first approximation, the half-life plastic strain energy could be calculated directly according to the equation without reckoning in the non-masing behavior. (C) 2004 Elsevier B.V. All rights reserved.
关键词:
low-cycle fatigue (LCF);bilinear behavior;slip band;fracture mode;nickel-based superalloy;nimonic 80a;deformation;mechanisms
张楠
,
董现春
,
张熹
,
陈延清
,
章军
机械工程材料
利用热模拟试验研究了钛微合金化SQ700MCD高强钢母材及热模拟粗晶热影响区（CGHAZ）的组织与第二相粒子的溶解及析出行为,对CGHAZ软化的原因进行了分析。结果表明：随着冷却时间（t8/5）的增加,CGHAZ的显微组织由板条状马氏体逐渐向粒状贝氏体转变,这是软化的原因之一;母材中的第二相粒子为碳氮化物,平均尺寸在10nm以下且弥散分布,而CGHAZ中绝大部分碳氮化合物粒子发生了回溶现象,弥散析出强化效果消失是软化的另一原因;未完全回溶粒子的尺寸随着t8/5的延长而增大,软化程度也逐渐增大。
关键词:
微合金化
,
第二相粒子
,
焊接
,
粗晶热影响区
,
软化
Hongchuan Jiang Chaojie Wang Wanli Zhang Xu Si Yanrong Li
材料科学技术（英文）
TaNx thin films were deposited on commercial polished Al2O3 ceramic substrates by reactive dc magnetron sputtering. The influences of the film thickness on the electrical properties of the samples were examined in detail. It is found that the film thickness does not influence the phase structures of the TaNx thin films. The sheet resistances of the samples shift from 173 Ω/sq. to 7.5 Ω/sq. with the film thickness shifting from 30 nm to 280 nm. With the increase of the film thickness from 30 nm to 280 nm, the temperature coefficient of resistance (TCR) of the samples shifts from negative value to positive value. When the film thickness is about 100 nm, TaNx thin films exhibits a near-zero TCR value (approximately -15×10-6/°C). This fact implies that TaNx thin films with a null TCR can be obtained by adjusting the film thickness. The variation in the electrical properties of the TaNx thin films with the film thickness can be qualitatively explained by the parallel connection of surface layer with high resistivity and negative TCR and TaNx layer with low resistivity and positive TCR.
关键词:
TaNx thin films
,
Film thickness
,
TCR
,
Sheet resistance
艾娇艳
,
何元锦
,
肖舜通
玻璃钢/复合材料
doi:10.3969/j.issn.1003-0999.2010.02.011
本文制备了碳纤维增强聚碳酸酯(PC)复合材料并研究了其性能,相比玻璃纤维增强PC,碳纤维增强PC在机械性能、电性能和加工性等方面有明显的提高.随着碳纤维含量的增加,拉伸强度、弯曲强度、弯曲模量明显呈上升趋势.而伸长率和冲击强度在碳纤维含量为6%时达最大值,分别为10.4%kJ/m~2和8.7kJ/m~2.加工流动性有了明显的提高,且随碳纤维含量的增加而逐渐降低.碳纤维的加入,也改善了PC的导电性,当碳纤维含量为10%时,导电电阻率已达到9.0×10~6Ω/sq.
关键词:
碳纤维
,
聚碳酸酯
,
复合材料
,
增强
缪灿锋
,
翟荣安
,
储成智
,
汝长海
电镀与涂饰
介绍了一种基于超声喷涂的电路印刷方法,适用于各种柔性材质的基体,可以更高效、更环保地完成柔性印刷电路(FPC)的制造.其主要思想是:纳米银导电油墨通过超声喷头雾化,进而喷涂在覆盖有金属掩膜版的聚酰亚胺(PI)膜基体上,低温烧结(125℃×20 min)之后就得到柔性电路.测试结果表明,图案化的导电线路(宽度为500 μm)经过多次弯曲后仍能保持良好的导电性,其表面方阻随喷涂层数的增多而稳定地减小,8层涂覆所得线路的方阻为(2l±2)mΩ/sq.扫描电镜观察表明,导电线路平整光滑,毛边误差在50 μm以内.
关键词:
电路
,
柔性印刷
,
聚酰亚胺薄膜
,
纳米银
,
导电油墨
,
超声喷涂
,
方阻
岳立福
,
孙晓刚
,
庞志鹏
,
吴小勇
,
聂艳艳
,
刘珍红
人工晶体学报
以碳纳米管醇分散剂TNADIS(粉末状聚合物分散剂)作为分散剂,同时应用超声振荡和高速剪切相互配合的工艺制成多壁碳纳米管(MWCNT)乙醇导电液.通过拉曼光谱,TEM和SEM表征MWCNTs的微观形态,通过离心,静置以及丁达尔效应的检测分析MWCNTs导电液的分散情况和稳定性.结果显示,添加0.05wt％分散剂时碳纳米管分散效果最佳,未石墨化MWCNTs的分散效果优于石墨化后的MWCNTs,且静置五个月后导电液依然保持良好的稳定性.应用此导电液通过旋涂工艺制得的涂覆均匀的MWCNTs透明导电薄膜,旋涂3min的透明导电薄膜方块电阻为0.34 kΩ/sq.
关键词:
多壁碳纳米管
,
石墨化
,
位阻排斥
,
分散
,
导电薄膜
孙洪涛
,
王小平
,
王丽军
,
王金烨
,
孙义清
,
李剑
,
文俊伟
,
刘凌鸿
,
于颖
材料科学与工程学报
采用电子束蒸发法成功制备了透明导电的ZnO/Mo/ZnO(ZMZ)复合薄膜,研究了不同的退火温度对其电学和光学性质的影响规律.利用X射线衍射仪、扫描电子显微镜、X射线能谱仪、紫外可见分光光度计和四探针测试仪等检测手段对样品的性能进行了分析.实验结果表明:随着退火温度的升高,薄膜的结晶程度提高,晶粒尺寸增大;薄膜的电阻率先降低后升高;薄膜的光学透过率先升高后降低.当退火温度为250℃时,ZnO/Mo/ZnO薄膜具有最佳的综合光电性能,在400nm～900nm波长范围内最高透过率为81.4％,平均透过率高于80％,最低电阻率为1.71×10-4Ω·cm,表面电阻为15.5Ω/sq.研究表明所制备的ZMZ复合透明导电薄膜可应用于太阳能电池、液晶显示器等领域.
关键词:
氧化锌
,
透明导电薄膜
,
多层膜
,
光电性能
Applied Physics Letters
We developed an ambient pressure chemical vapor deposition (CVD) for rapid growth of high-quality graphene films on Cu foils. The quality and growth rate of graphene films are dramatically increased with decreasing H(2) concentration. Without the presence of H(2), continuous graphene films are obtained with a mean sheet resistance of < 350 Omega/sq and light transmittance of 96.3% at 550 nm. Because of the ambient pressure, rapid growth rate, absence of H(2) and readily available Cu foils, this CVD process enables inexpensive and high-throughput growth of high-quality graphene films. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3512865]
关键词:
Xuyan XUE
,
Chunlei WANG
,
Weilie ZHONG
材料科学技术（英文）
The crystal and electronic structure of antiferroelectric squaric acid is studied using density functional theory method, and the exchange correlation effects are treated by the generalized approximation. In order to understand the ferroelectricity of H2SQ in the molecular plane and the antiferroelectricity in whole crystal, the density of states, charge density distribution and band structure are calculated. The result showed that O2p and C2p play important roles in the interactions between layers. The hybridizations of O2s-H1s and O2p-H1s are responsible for the tendency to ferroelectricity within each layer.
关键词:
Antiferroelectricity
,
null
,
null
