IN-SITU ELECTRON MICROSCOPY STUDY ON PRECIPITATION OF ZIRCONIUM HYDRIDES INDUCED BY STRESS AND STRAIN IN ZIRCALOY-2

The precipitation process of zirconium hydrides induced by stress and strain was investigatedby means of electron microscopy in-situ.The precipitating hydrides induced by stress werefound to be γ phase with orientation relationship of (110)_γ‖(110)_(αZr),(001)_γ‖(0001)_(αZr) between γ-hydrides and surrounding matrix.The growth rate of γ-hydrides whichwas much faster along [110] direction brought them in taper shape.After fracture ofy-hydrides,a new one will precipitate at the tip of cracks.This is the essential process ofhydrogen-induced delayed cracking in Zircaloy.The precipitating hydrides induced by strainwere found to be δ phase with both orientation relationships of(111)_δ‖(0001)_(αZr),(110)_δ‖(110)_(αZr) or (010)_δ‖(0001)_(αZr),(001)_δ‖(110)_(αZr)between δ-hydride and surroundingmatrix.The δ-hydrides become much finer as the strain rate increased.     

STUDIES ON PRIMARY CRYSTALLIZATION OF RAPIDLY QUENCHED Al-Ni-Cu-Nd METALLIC GLASS BY USING HIGH RESOLUTION TRASMISSION ELECTRON MICROSCOPY

Rapidly solidified Al87Ni7Cu3Nd3 metallic glasses, prepared by using melt spinning, were treated under both isothermal and non-isothermal regime. The amorphous ribbon and the annealed samples were closely examined by means of differential scanning calorimetric, conventional X-ray diffraction and high resolution transmission electron microscopy with selected-area electron diffraction, with special interest in primary crystallization into α-Al nanocrystalline particles, in order to understand structural characteristics of Al-based amorphous/nanocrystalline alloys, and nucleation and grain growth mechanism on the nanometer scale during primary crystallization. The results show that, the as-prepared ribbons are fully amorphous and homogeneous in the micron scale, but contain high density of quenched-in clusters or crystallite embryos. Primary crystallization mainly leads to formation of two-phase mixture of a-Al crystal and residual amorphous phase. The annealed ribbons exposed isother-mally at HOP C for 5     

MEASUREMENT OF VACANCY MIGRATION ENERGY BY ELECTRON IRRADIATION

A method together with a new formula were developed for measuring the vacancy migrationenergy on HVEM considering the effect of surface sink of specimen on point defects.The va-cancy migration energy may be calculated through the loop growth rate under electronirradiation at various temperatures.     

TEXTURE DETERMINATION OF THIN FILM ZrO_2 BY ELECTRON DIFFRACTION

A method for semi-quantitative determination of thin film texture using electron diffrac-tion is described.The texture state of a zirconia thin film with a cubic structure hasbeen determined in this way and is presented as an example.     

THE INFLUENCE OF ISLAND-INDUCED STRAIN ON THE Si SURFACE MORPHOLOGY IN Ge-Si MULTILAYERS： A TRANSMISSION ELECTRON MICROSCOPY STUDY

1.IntroductionA n active field ofresearch concernsthe fabrication and investigation ofquantum dotand quantumw ire structuresw hich could becom e the basisforfuture nanoelectronics.W ith deposition by low-pres-sure chem icalvapourdeposition(LPCV D)techniqu…     

CHARACTERIZATION OF VELOCITY SINGULARITY AND SUPPRESSION OF NOISE

ＣＨＡＲＡＣＴＥＲＩＺＡＴＩＯＮＯＦＶＥＬＯＣＩＴＹＳＩＮＧＵＬＡＲＩＴＹＡＮＤＳＵＰＰＲＥＳＳＩＯＮＯＦＮＯＩＳＥ￥Ｓｏｎｇ，ＳｈｏｕｇｅｎＴａｎｇ，Ｊｉｎｔｉａｎ（ＤｅｐａｒｔｍｅｎｔｏｆＧｅｏｌｏｇｙ，ＣｅｎｔｒａｌＳｏｕｔｈＵｎｉｖｅｒｓｉｔ...     

VALENCE ELECTRON STRUCTURE ANALYSIS OF ε-Fe_3C IN BAINITE FORMED BY AUSTENITE LOWTEMPERATURE DECOMPOSITION

利用最近发表的固体与分子经验电子理论,根据已有的晶体结构资料,对ε-Fe_3C的价电子结构进行了分析。通过键距差分析和原子磁距等两方面的论证得出 结论:1.在ε-Fe_3C中,碳原子处于第6杂阶,Fe原子处于甲种杂化的第11阶; 2.它具有n_4(Fe-c)键,且有n_A=0.8440;3.n_A键在空间分布极为规则,形成三维的规则的网状结构,预期该结构应有大的机械强度和低温稳定性;4.就机械强度和硬度来说ε-Fe_3C可能比渗碳体Fe_3C小些,但由于前者的n_A键比后者在空间分布更为均衡,故ε-Fe_3C可能不像渗碳体Fe_3C那样脆。     

PREPARATION AND SURFACE CHARACTERIZATION OF TiO_2 THIN FILMS ON GLASS BY MAGNETRON SPUTTERING METHOD

1. IntroductionTiOz thin films have excellent properties sucl1 as l1igh ref1actitre il1dex, outstal1diugoptical tra11sl11ittallce, high dielectric constant and physical chemical stabilityll'2]. Recently',the TiO2 thi1l films have drawn more attel1tions oll photocatalysis, optical coating, al1dsolar cell fab.ication[3'4l. In this work we deposited Ti thin film on glass substrate b}-nlagl1etroll sputterillg lllethod and allllealing Ti tl1in fi1l11 to fOrlll TiO2 tl1ill fi1m.2. ExperimelltalT…     

ANALYSIS OF DRAWING UNDER LUBRICATION OF NON-NEWTONIAN LUBRICATING MATERIALS

ＡＮＡＬＹＳＩＳＯＦＤＲＡＷＩＮＧＵＮＤＥＲＬＵＢＲＩＣＡＴＩＯＮＯＦＮＯＮ－ＮＥＷＴＯＮＩＡＮＬＵＢＲＩＣＡＴＩＮＧＭＡＴＥＲＩＡＬＳＬｅｉＺｈａｎｂｏ；ＷａｎｇＺｈａｎｘｕｅ；ＧａｏＹｏｕｚｈｉ（ＤｅｐａｒｔｍｅｎｔｏｆＭｅｃｈａｎｉｃａｌＥｎｇ...     

ANALYSIS OF VALENCE ELECTRON STRUCTURE OF Fe-Cr σ-PHASE

本文用经验电子论的键距差分析法计算了Fe-Cr“σ”相的价电子结构,结果表明σ相中存在原子间共价电子数的明显不均匀性.可以认定,这种不均匀性是σ相脆性的原因之一.     

电流体动力学技术制备纳米超微粉的研究

应用电流体动力学技术，采用石英毛细管喷嘴，制备了Sn-Bi纳米超微粉，研究了工艺参数对纳米超微粉尺寸的影响,实验结果表明：随着直流高压的增加和毛细管直径的减小,Sn-Bi纳米超微粉的尺寸减小，输送熔体的压力对控制纳米超微粉的尺寸也是一个重要影响因素。     

惰性气体凝聚法制备纳米NiAl合金的结构及磁特性

用Ｘ射线衍射及透射电镜研究用惰性气体凝聚法制备纳米ＮｉＡｌ合金固体的结构。结果表明，纳米ＮｉＡｌ合金晶体结构与常规ＮｉＡｌ结构一致，平均粒度为８．６ｎｍ，，具有较大的晶格畸变，长程有序度有所降低。退火实验显示，当温度低于８００Ｋ时晶粒不明显长大，具有较好的抗晶粒生长能力。     

TiAl-W-Si合金中的偏析与析出相的分析电子显微术研究

用高空间分辨分析电子显微术研究了TiAl-W-Si合金中B2相的析出行为和元素W的分布.结果表明,α2/γ相界面台阶由于W的富集而成为B2析出相的择尤形核位置.B2相中,高达三分之一的Al原子被W原子置换,而在γ相中只固溶了很有限的W.另外,W也偏析在α2/γ和B2/γ相界面上.这些结果合理地解释了W对提高TiAl合金蠕变性能的显著作用.     

CONTAMINATION LINE METHOD AND COMPARISON OF FOIL THICKNESS MEASUREMENT METHODS IN TRANSMISSION ELECTRON MICROSCOPY

The paper brieflv introduces the Contamination Line Method for foil thicknessmeasurement in transmission electron microscopy and compares it with four conventionalmethods:the convergent beam diffraction method,thecontamination spor method,themethods based on characteristic X-rav emission and cominuous X-rav emission on the epplication,operation and accuracvetc.     

静压下扩散反应形成块状Al-Fe(Mo,Si,B)纳米合金

在静压３ＧＰａ，５７０－８５０℃下、对熔融Ａｌ与固态非晶（Ｆｅ０．９９，Ｍｏ０．０１）７８Ｓｉ９Ｂ１３进行界面扩散反应，于８００－８３０℃：加热２０ｍｉｎ。制备出单相Ａｌ－Ｆｅ（Ｍｏ，Ｓｉ，Ｂ）纳米合金块，其晶体结构属正交晶系，平均晶粒度为２２ｎｍ。具有较好的热稳定性，ＨＶ为６．９ＧＰａ．     

简谈电子材料的腐蚀

简单论述了因空气污染,塑料和有机物分解气体等导致电子材料的腐蚀原理及原因。     

TRANSMISSION ELECTRON MICROSCOPY INVESTIGATIONS OF LOW-PRESSURE CVD GROWTH AND STRAIN RELAXATION OF Ge ISLANDS ON Si(110)

1. IntroductionSelf-assem bled grow th ofsem iconductorislandshasbecom e an im portanttopic ofcurrentresearchboth experim entally[1,2] and theoretically[3] due to the observed low -dim ensionalcarrierconfinem entef-fects[4].M aterialssystem sw ith a high …     

电子束蒸发沉积Al-Cr合金涂层研究

研究了电子束蒸发镀沉积Al-Cr合金涂层的工艺，探讨了铬含量对涂层耐蚀性的影响。对涂层的物相、形貌以及热处理对涂层和基体之间热扩散的影响进行了分析．结果表明：涂层中铬含量与膜料中铬含量有较大差异；在温度为283K，30g／L NaCl溶液中含1.5％Cr、2.5％Cr、5％Cr的Al-Cr合金涂层的自腐蚀电位均比普通钢基材的电位负，因此它们作为阳极性涂层对普通钢基材能起到较好的电化学保护；涂层为晶态组织，其物相为Al和少量的Cr9Al17。随膜料中Cr含量的增加，其生成的Cr9Al17的量也随之增多；在真空蒸镀时涂层沉积有方向性；对涂层进行600℃，lh热处理后，涂层与基体间元素产生了互扩散．     

电子束辐照诱导Al2Ni3相的析出

用４００ｋＶ透射电镜观察由Ｎ９Ｒ及２Ｈ马氏体组成的淬火Ｃｕ－１１．２Ａｌ－２．９Ｎｉ合金样品时，发现大量弥散相因电子束辐照而析出。电子衍射分析证实析出相为Ａｌ２Ｎｉ３。暗场像体视测量与高分辨显微术研究表明，辐照诱导析出不仅是表面反应。Ａｌ２Ｎｉ３粒子择优在晶体缺陷及马氏体界面处析出。延长辐照时间，析出相长大并粗化。