Al/Cu微米级厚度薄膜扩散连接工艺及显微组织分析

采用真空扩散连接工艺法,对Al与Cu薄膜扩散连接接头的组织性能进行实验研究,利用扫描电子显微镜(SEM)、X射线衍射(XRD)仪等测试方法对连接接头过渡区及基体组织和性能进行了分析.实验结果表明采用真空扩散连接工艺,加热温度为250℃、保温时间为30 min、压力为5 MPa时,Al/Cu薄膜界面处形成明显的过渡区,扩散界面控制在150 nm以内.     

射流圆孔靶的制备和靶参数测量

介绍了X射线激光射流实验中Al和CH两种射流圆孔靶的制备方法。分别采用精密机械和皮秒激光加工工艺在Al和CH薄膜上制备精密、微小的圆孔,再通过精密装配的方法获得射流圆孔靶。使用白光干涉仪和小型量测仪对射流圆孔靶进行靶参数测量,测量图像和数据表明,Al和CH薄膜圆孔的孔径较圆且两面大小一致性较好,靶的两层薄膜分界面清晰且连接紧密。     

GH3535合金表面渗铝层原位氧化工艺研究

高温工况下钍基熔盐堆中存在氚泄漏的风险，建立氚渗透屏障涂层有助于应对这一问题。采用包埋渗铝和原位氧化工艺，在GH3535合金表面制备了Al2O3/Ni-Al复合阻氚涂层，重点分析了氧化温度和真空度对氧化铝薄膜微观结构的影响。利用掠入射X射线衍射、扫描电子显微镜、透射电子显微镜等手段对氧化铝薄膜表面及截面的微观形貌、相构成进行了实验分析。实验结果表明：低氧分压能降低氧化铝薄膜的形成速度，促进形成更致密、表面平整的薄膜；高的氧化温度有利于形成α相氧化铝及更厚的氧化铝薄膜，但会大大增加表面缺陷。1.2 Pa真空度气氛、850℃氧化温度、72 h氧化时间是较优的原位氧化工艺参数，可以在GH3535合金基体表面获得性能较好的氧化铝薄膜，其相结构为γ和α相，厚度约为0.8μm，且表面致密无缺陷。     

2219铝合金搅拌摩擦焊和钨极保护焊残余应力的中子衍射和有限元方法研究

正利用中子衍射法对2219铝合金搅拌摩擦焊(FSW)和非熔化极惰性气体钨极保护焊(TIG)焊接件开展了三维残余应力测量,并对残余应力分布规律进行了分析,结果示于图1。结果表明:焊接件的纵向残余应力数值较大;FSW焊接残余应力整体小于TIG焊;FSW焊接和TIG焊接残余     

AlNi纳米合金薄膜低温电阻率的特性研究

通过磁控溅射制备了AlNi纳米合金薄膜,并利用自制的直排四探针低温测量系统测量了薄膜电阻率随温度(8~300K)的变化规律。结果表明:由于电子-声子和电子-磁子相互作用,纯Al和Ni纳米晶薄膜的电阻率分别呈现出正的电阻率温度系数,且电子-磁子散射对电阻率的贡献主要体现在高温区(80~300K),在低温区(40K)电子-晶界/表面散射对电阻率的贡献占主导地位。Ni原子掺入量的增加,诱导了纳米晶薄膜无序程度的增强,从而使Al1-xNix纳米合金薄膜逐渐由晶体的金属特性过渡到半导体特性,导致其呈现出负的电阻率温度系数。由于增强的电子极化效应,Al1-xNix纳米合金薄膜电阻率与温度的关系并不完全遵循半导体的热激发导电模型。     

适合核能可持续发展的焊接技术——印度的展望

在印度乃至全世界,核反应堆材料焊接技术的发展是经济的、安全的、环保的核能可持续发展的关键。新的、改进的、不同的核反应堆材料需要与最前端的焊接技术相适应,以确保核能的成本竞争力。现今成熟的焊接科学已经用于开发适合高级的／改进的材料的焊接产品,同时在现有的核电厂中发展适合的焊接修复技术。一些新型焊接技术,如钨极隋性气体（TIG）活化焊、搅拌摩擦焊和混合焊已经在核反应堆构件的制造中实现了工业应用。在确保高质量焊接过程中,将会增加人工神经网络等工具的应用。从长远看,聚变技术的发展在很大程度上将依赖合适的材料焊接技术的发展,如低活性铁素体-马氏体双相钢和氧化物弥散强化合金。     

某核电厂混凝土底板模块化吊装设计及应用

针对某核电厂混凝土底板模块重心偏离几何中心的情况,在充分利用预设吊点基础上,设计采用焊接H型钢构架进行吊装的专用连接系统。应用Ansys软件建立数学模型,对吊装构架、吊耳及销轴滚轮等进行应力及应变分析和评价。结果表明焊接H型钢吊装构架结构安全可靠、吊装参数设计合理。利用移动式起重机,架设液压顶升塔和吊装梁、连接吊装构架以及劳辛格调平等复杂工艺过程,完成整体吊装。     

TiO2薄膜的制备及光催化活性研究

采用溶胶-凝胶法以浸渍提拉方式在玻璃管上制备了TiO2薄膜，制得的TiO2薄膜均匀、结实，催化活性好。利用此薄膜对庚烷进行气相光催化降解，结果表明：TiO2薄膜的光催化活性随焙烧温度降低而升高，300℃制备的薄膜的光催化活性较好。在此温度下制备的薄膜，光催化活性随着负载层数的增加逐渐增加。薄膜稳定性好，长期放置和反复使用光催化活性基本不降低。利用该薄膜还对丙酮、苯、甲苯和1，2-二氯乙烷进行了气相光催化降解，结果表明：苯和甲苯降解比较缓慢，而丙酮和1，2-二氯乙烷则与庚烷相似，很快降解并生成近似化学计量比的二氧化碳。     

ICF靶用纳米厚金属薄膜中超声波的激光激励

简要介绍了激光超声和干涉仪检测原理,实现了一个激光超声实验。实验中,用调Q Nd:YAG固体激光器在超薄薄膜200 nm Al/Au/Ag中激励高频超声,用迈克尔逊干涉仪对超声进行了检测,对获得的信号进行傅里叶变换,获得了激励的振动频率。3种薄膜中产生的单一频率的超声振动分别为32.36、26.17和29.39 MHz。本工作对纳米薄膜的超声检测有一定的参考和借鉴作用。     

铍/铝镁合金YAG激光焊接工艺及微观组织分析

利用YAG激光焊接了铍/铝镁合金环,探索出合理的焊接工艺参数,采用扫描电镜及电子探针对铍/铝镁合金焊接接头的组织结构进行了研究。冷却速度对显微组织的形成影响明显,在靠母材的焊缝两侧,焊缝的显微组织为树枝晶,而焊缝的中心为等轴晶;在焊缝处主要存在焊接热裂纹及夹杂物,对夹杂物的能谱分析表明,其主要由C、O、Al、Mg、F、Cl等元素组成;对焊缝的面扫描结果表明,C、O等元素在焊缝的表面存在偏析,而Be与Mg分布较为均匀。     

POLYVINYLIDENE FLUORIDE TRACK MICROFILTER

By the etching of PVDF(polyvinylidene)foils perpendicularly bombarded to their surfaces in advance with heavy ions at UNILAC(GSI Darmstadt,Germany),PVDF track microfilters are successfully manufactured and mostly evaluated by means of an optical microscope.The recipes of the elaboration,the properties as well as etching and technical parameters of the microfilters are summarized.The possible applications are also discussed briefly.     

Stopping power measurements for O, F and Si ions in Mylar by a transmission technique

Electronic energy loss of charged particles in materials is a fundamental process responsible for the unique response of materials in applications of advanced nuclear power, radiation detectors and advanced processing of electronic devices. In this study, stopping powers of ¹⁶O, ¹⁹F and ²⁸Si heavy ions crossing thin Mylar foils have been determined in transmission geometry. The energy loss was measured over a continuous range of energies from 1.6 to 5.5 MeV/n (MeV per nucleon) using the data that was tagged by a surface barrier detector (SBD) with and without stopping foils. We have compared the obtained stopping values to those predicted by SRIM-2008 computer code, ICRU-73 stopping data tables and MSTAR calculations. The effective charge values of these heavy ions have been also deduced from the experimental set of data.     

炭/炭复合材料对活化片辐照的影响

根据钍基熔盐堆高温环境辐射测量需求,采用具有高温抗氧化Si C涂层的炭/炭复合材料作为待测活化片的载体材料,介绍了采用炭/炭复合材料作为辐照载体的优越性,对其进行了成分和热分析测试,并详细描述了带有炭/炭复合材料的一组活化片和不带有炭/炭复合材料的另一组活化片同时在铀氢锆脉冲堆的径向实验孔道中进行中子辐照的实验过程。通过比较两组活化片的单核反应率,详细分析了炭/炭复合材料对活化片辐照结果的影响。结果表明,载体采用涂层为Si C的炭/炭复合材料,并且壁厚为几个毫米时,对多种活化片的中子辐照结果影响很小,可以作为高温环境下辐照材料的载体。     

类金刚石碳剥离膜的制备及其性能研究

采用磁过滤阴极真空弧(FCVA)技术制备了质量厚度为5~7μg/cm2的类金刚石碳(DLC)剥离膜。用XP2U型精密电子天平测试分析了100mm范围内的DLC剥离膜均匀性,结果显示其最大不均匀性小于10%。通过扫描电子显微镜(SEM)、原子力显微镜(AFM)、万能摩擦磨损试验机和X光电子谱(XPS)测试分析了DLC剥离膜的表面形貌、耐磨损特性和结构,结果显示采用双90°FCVA技术沉积的DLC剥离膜表面光滑致密、耐磨,几乎没有大颗粒的污染,表征金刚石特性的sp3键含量超过70%。在北京HI-13串列加速器上使用107 Ag-、70 Ge-、48 Ti-、28Si-、197 Au-和127I-六种典型质量的离子束对质量厚度为5~7μg/cm2的DLC剥离膜和碳剥离膜寿命进行测试比较,结果显示DLC剥离膜寿命比碳剥离膜的高2.6~10倍。     

Study of individual atmospheric aerosol particles at the Debrecen ion microprobe

Aerosol samples collected in outside and indoor environments with a 9-stage PI cascade impactor were analysed using PIXE, STIM (on and off-axis) and RBS ion beam analytical techniques at the Debrecen ion microprobe. Elemental composition, size and morphology of single aerosol particles were determined.Since the quantitative determination of light element concentrations requires a support material with small or no light element content, impactor surfaces made of different materials were tested in order to optimize the sampling and analysis. Thin polymer and Al foils were found to be possibly adequate substrate materials.     

Enhanced beam quality for proton microprobes using ultrathin stripper foils in tandem accelerators

Ultrathin carbon foils (0.5 μ/cm².+) have been used as stripper foils in a tandem accelerator. The spread in the ion beam caused by scattering in ultrathin foils has been compared with the spread due to thicker carbon foils and a gas stripper. A proton beam was used at a terminal voltage of 1.3 MV. The results show a significantly smaller beam spread due to the thinnest foils, even compared with the gas stripping. The smaller beam spread and the more stable terminal voltage compared with gas stripping make the ultrathin carbon foil strippers preferable, especially for proton microprobe applications.     

Dislocation loop nucleation and growth in zirconium-2.5 wt% niobium alloy during 1 MeV electron irradiation

A high voltage electron microscope has been used to study loop formation in thin foils of Zr, Zircaloy and two Zr-Nb alloys. The effects of varying irradiation temperature and displacement dose were examined in the light of nucleation and growth theories. It was found that Nb solute enhanced loop densities by up to more than an order of magnitude but loop growth at 773 K was more than proportionately retarded so that total point defect precipitation is diminished. The temperature dependence of loop density corresponds to an activation energy 0.36 eV with <0.1 eV solute binding.     

Energy loss of 450–2400 kev protons in Havar,Kapton and aluminized Mylar foils

The energy loss of 450–2400 keV protons in common exit foils used in external beam setups has been determined. The measured foils consisted of 2.4 μm Havar, 9.9 μm Kapton and 3.5 μm and 6.6 μm aluminized (40 nm Al) Mylar. Good agreement with the calculations by using Bragg's rule and the Andersen and Ziegler parameters was found in the higher energy region. At energies ? 1000 keV, the results are higher ( ? 6%) than the calculated values. A rapid decrease of the energy loss in the Mylar foils under proton exposure was detected.     

Neutronics diagnostics for European ITER TBMs: Activation foil spectrometer for short measurement cycles

An important aim of neutronics Test Blanket Module (TBM) experiments in ITER will be to check the prediction accuracy of nuclear responses in an environment closer to a future fusion power reactor than so far provided by existing facilities. The development of measurement methods suitable for the harsh environment in an ITER TBM has been addressed in several recent R&D programs supported by Euratom. Within this framework, KIT is developing an activation foil spectrometer for the measurement of local neutron flux densities in the TBM. We intend to establish a measurement method which allows to record the induced activities in small packages of activation foils simultaneously and to calculate the corresponding spectral neutron flux densities with moderate time resolution of tens of seconds immediately after extraction from the TBM. In the present work we propose a candidate set of activation foil materials which cover the neutron energy range from thermal to 14 MeV. In order to assess their basic suitability for such measurements, we have computed induced gamma-ray activities in the foils using a calculated neutron spectrum in a representative position in the European HCPB TBM assuming a short irradiation time of 30 s. In a further step we have investigated pulse height spectra which would be obtained in a typical gamma-ray measurement arrangement in a HPGe detector and concluded that the proposed set of activation foils should be basically suitable for such a measurement system but require improvement of relevant cross sections uncertainties.     

Ion-luminescence properties of GaN films being developed for IPEM

Radiation effects microscopy (REM) for the next generation integrated circuits (ICs) will require GeV ions both to provide high ionization and to penetrate the thick overlayers in present day ICs. These ion beams can be provided by only a few cyclotrons in the world. Since it is extremely hard to focus these higher-energy ions, we have proposed the ion photon emission microscope (IPEM) that allows the determination of the ion hits by focusing the emitted photons to a position sensitive detector. The IPEM needs a thin luminescent foil that has high brightness, good spatial resolution and does not change the incident ion’s energy and direction significantly. Available organic-phosphor foils require a large thickness to produce enough photons, which results in poor spatial resolution. To solve this problem, we have developed thin, lightly doped n-type GaN films that are extremely bright. We have grown high quality GaN films on sapphire using metal organic chemical vapor deposition (MOCVD), detached the films from the substrate using laser ablation, and made them self-supporting. The smallest foils have 1 mm² area and 1 μm thickness. The optical properties, such as light yield, spectrum and decay times were measured and compared to those of conventional phosphors, by using both alpha particles from a radioactive source and 250 keV ions from an implanter. We found that the GaN performance strongly depends on composition and doping levels. The conclusion is that 1-2 μm GaN film of a 1 mm² area may become an ideal ion position detector.