Single-crystal laser deposition of superalloys-processing–microstructure maps
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光电技术专业英语词汇
《光电技术》专业英语词汇1.Absorption coefficient 吸收系数2.Acceptance angle 接收角3.fibers 光纤4.Acceptors in semiconductors 半导体接收器5.Acousto-optic modulator 声光调制6.Bragg diffraction 布拉格衍射7.Air disk 艾里斑8.angular radius 角半径9.Airy rings 艾里环10.anisotropy 各向异性11.optical 光学的12.refractive index 各向异性13.Antireflection coating 抗反膜14.Argon-ion laser 氩离子激光器15.Attenuation coefficient 衰减系数16.Avalanche 雪崩17.breakdown voltage 击穿电压18.multiplication factor 倍增因子19.noise 燥声20.Avalanche photodiode(APD) 雪崩二极管21.absorption region in APD APD 吸收区域22.characteristics-table 特性表格23.guard ring 保护环24.internal gain 内增益25.noise 噪声26.photogeneration 光子再生27.primary photocurrent 起始光电流28.principle 原理29.responsivity of InGaAs InGaAs 响应度30.separate absorption and multiplication(SAM) 分离吸收和倍增31.separate absorption grading and multiplication(SAGM) 分离吸收等级和倍增32.silicon 硅33.Average irradiance 平均照度34.Bandgap 带隙35.energy gap 能级带隙36.bandgap diagram 带隙图37.Bandwidth 带宽38.Beam 光束39.Beam splitter cube立方分束器40.Biaxial crystals 双轴晶体41.Birefringent 双折射42.Bit rate 位率43.Black body radiation law 黑体辐射法则44.Bloch wave in a crystal 晶体中布洛赫波45.Boundary conditions 边界条件46.Bragg angle 布拉格角度47.Bragg diffraction condition 布拉格衍射条件48.Bragg wavelength 布拉格波长49.Brewster angle 布鲁斯特角50.Brewster window 布鲁斯特窗51.Calcite霰石52.Carrier confinement 载流子限制53.Centrosymmetric crystals 中心对称晶体54.Chirping 啁啾55.Cladding覆层56.Coefficient of index grating 指数光栅系数57.Coherence 连贯性pensation doping 掺杂补偿59.Conduction band 导带60.Conductivity 导电性61.Confining layers 限制层62.Conjugate image 共轭像63.Cut-off wavelength 截止波长64.Degenerate semiconductor简并半导体65.Density of states 态密度66.Depletion layer 耗尽层67.Detectivity 探测率68.Dielectric mirrors 介电质镜像69.Diffraction 衍射70.Diffraction grating 衍射光栅71.Diffraction grating equation 衍射光栅等式72.Diffusion current 扩散电流73.Diffusion flux 扩散流量74.Diffusion Length 扩散长度75.Diode equation 二极管公式76.Diode ideality factor 二极管理想因子77.Direct recombination 直接复合78.Dispersion 散射79.Dispersive medium 散射介质80.Distributed Bragg reflector 分布布拉格反射器81.Donors in semiconductors 施主离子82.Doppler broadened linewidth 多普勒扩展线宽83.Doppler effect 多普勒效应84.Doppler shift 多普勒位移85.Doppler-heterostructure 多普勒同质结构86.Drift mobility漂移迁移率87.Drift Velocity 漂移速度88.Effective density of states 有效态密度89.Effective mass 有效质量90.Efficiency 效率91.Einstein coefficients 爱因斯坦系数92.Electrical bandwidth of fibers 光纤电子带宽93.Electromagnetic wave 电磁波94.Electron affinity 电子亲和势95.Electron potential energy in a crystal 晶体电子阱能量96.Electro-optic effects 光电子效应97.Energy band 能量带宽98.Energy band diagram 能量带宽图99.Energy level 能级100.Epitaxial growth外延生长101.Erbium doped fiber amplifier 掺饵光纤放大器102.Excess carrier distribution 过剩载流子扩散103.External photocurrent 外部光电流104.Extrinsic semiconductors 本征半导体105.Fabry-Perot laser amplifier 法布里-珀罗激光放大器106.Fabry-Perot optical resonator 法布里-珀罗光谐振器107.Faraday effect 法拉第效应108.Fermi-Dirac function 费米狄拉克结109.Fermi energy 费米能级110.Fill factor 填充因子111.Free spectral range 自由谱范围112.Fresnel’s equations菲涅耳方程113.Fresnel’s optical indicatrix 菲涅耳椭圆球114.Full width at half maximum半峰宽115.Full width at half power半功率带宽116.Gaussian beam 高斯光束117.Gaussian dispersion 高斯散射118.Gaussian pulse 高斯脉冲119.Glass perform玻璃预制棒120.Goos Haenchen phase shift Goos Haenchen相位移121.Graded index rod lens 梯度折射率棒透镜122.Group delay 群延迟123.Group velocity 群参数124.Half-wave plate retarder 半波延迟器125.Helium-Neon laser氦氖激光器126.Heterojunction 异质结127.Heterostructure 异质结构128.Hole 空穴129.Hologram 全息图130.Holography 全息照相131.Homojunction 同质结132.Huygens-Fresnel principle惠更斯-菲涅耳原理133.Impact-ionization 碰撞电离134.Index matching 指数匹配135.Injection 注射136.Instantaneous irradiance 自发辐射137.Integrated optics 集成光路138.Intensity of light 光强139.Intersymbol interference 符号间干扰140.Intrinsic concentration本征浓度141.Intrinsic semiconductors 本征半导体142.Irradiance 辐射SER 激光144.active medium 活动介质145.active region 活动区域146.amplifiers 放大器147.cleaved-coupled-cavity解理耦合腔148.distributed Bragg reflection 分布布拉格反射149.distributed feedback 分布反馈150.efficiency of the He-Ne 氦氖效率151.multiple quantum well 多量子阱152.oscillation condition 振荡条件ser diode 激光二极管sing emission 激光发射155.LED 发光二极管156.Lineshape function 线形结157.Linewidth 线宽158.Lithium niobate铌酸锂159.Load line 负载线160.Loss coefficient 损耗系数161.Mazh-Zehnder modulator Mazh-Zehnder型调制器162.Macrobending loss 宏弯损耗163.Magneto-optic effects 磁光效应164.Magneto-optic isolator 磁光隔离165.Magneto-optic modulator 磁光调制166.Majority carriers 多数载流子167.Matrix emitter 矩阵发射168.Maximum acceptance angle 最优接收角169.Maxwell’s wave equation 麦克斯维方程170.Microbending loss 微弯损耗171.Microlaser 微型激光172.Minority carriers 少数载流子173.Modulated directional coupler 调制定向偶合器174.Modulation of light 光调制175.Monochromatic wave 单色光176.Multiplication region 倍增区177.Negative absolute temperature 负温度系数 round-trip optical gain 环路净光增益179.Noise 噪声180.Noncentrosymmetric crystals 非中心对称晶体181.Nondegenerate semiconductors 非简并半异体182.Non-linear optic 非线性光学183.Non-thermal equilibrium 非热平衡184.Normalized frequency 归一化频率185.Normalized index difference 归一化指数差异186.Normalized propagation constant 归一化传播常数187.Normalized thickness 归一化厚度188.Numerical aperture 孔径189.Optic axis 光轴190.Optical activity 光活性191.Optical anisotropy 光各向异性192.Optical bandwidth 光带宽193.Optical cavity 光腔194.Optical divergence 光发散195.Optic fibers 光纤196.Optical fiber amplifier 光纤放大器197.Optical field 光场198.Optical gain 光增益199.Optical indicatrix 光随圆球200.Optical isolater 光隔离器201.Optical Laser amplifiers 激光放大器202.Optical modulators 光调制器203.Optical pumping 光泵浦204.Optical resonator 光谐振器205.Optical tunneling光学通道206.Optical isotropic光学各向同性的207.Outside vapor deposition管外气相淀积208.Penetration depth 渗透深度209.Phase change 相位改变210.Phase condition in lasers 激光相条件211.Phase matching 相位匹配212.Phase matching angle 相位匹配角213.Phase mismatch 相位失配214.Phase modulation 相位调制215.Phase modulator 相位调制器216.Phase of a wave 波相217.Phase velocity 相速218.Phonon 光子219.Photoconductive detector 光导探测器220.Photoconductive gain 光导增益221.Photoconductivity 光导性222.Photocurrent 光电流223.Photodetector 光探测器224.Photodiode 光电二极管225.Photoelastic effect 光弹效应226.Photogeneration 光子再生227.Photon amplification 光子放大228.Photon confinement 光子限制229.Photortansistor 光电三极管230.Photovoltaic devices 光伏器件231.Piezoelectric effect 压电效应232.Planck’s radiation distribution law 普朗克辐射法则233.Pockels cell modulator 普克尔斯调制器234.Pockel coefficients 普克尔斯系数235.Pockels phase modulator 普克尔斯相位调制器236.Polarization 极化237.Polarization transmission matrix 极化传输矩阵238.Population inversion 粒子数反转239.Poynting vector能流密度向量240.Preform 预制棒241.Propagation constant 传播常数242.Pumping 泵浦243.Pyroelectric detectors 热释电探测器244.Quantum efficiency 量子效应245.Quantum noise 量子噪声246.Quantum well 量子阱247.Quarter-wave plate retarder 四分之一波长延迟248.Radiant sensitivity 辐射敏感性249.Ramo’s theorem拉莫定理250.Rate equations速率方程251.Rayleigh criterion 瑞利条件252.Rayleigh scattering limit 瑞利散射极限253.Real image 实像254.Recombination 复合255.Recombination lifetime 复合寿命256.Reflectance 反射257.Reflection 反射258.Refracted light 折射光259.Refractive index 折射系数260.Resolving power分辩力261.Response time 响应时间262.Return-to-zero data rate 归零码263.Rise time 上升时间264.Saturation drift velocity 饱和漂移速度265.Scattering 散射266.Second harmonic generation 二阶谐波267.Self-phase modulation 自相位调制268.Sellmeier dispersion equation色列米尔波散方程式269.Shockley equation肖克利公式270.Shot noise肖特基噪声271.Signal to noise ratio 信噪比272.Single frequency lasers 单波长噪声273.Single quantum well 单量子阱274.Snell’s law斯涅尔定律275.Solar cell 光电池276.Solid state photomultiplier 固态光复用器277.Spectral intensity 谱强度278.Spectral responsivity 光谱响应279.Spontaneous emission 自发辐射280.stimulated emission 受激辐射281.Terrestrial light 陆地光282.Theraml equilibrium热平衡283.Thermal generation 热再生284.Thermal velocity 热速度285.Thershold concentration 光强阈值286.Threshold current 阈值电流287.Threshold wavelength 阈值波长288.Total acceptance angle 全接受角289.Totla internal reflection 全反射290.Transfer distance 转移距离291.Transit time 渡越时间292.Transmission coefficient 传输系数293.Tramsmittance 传输294.Transverse electric field 电横波场295.Tranverse magnetic field 磁横波场296.Traveling vave lase 行波激光器297.Uniaxial crystals 单轴晶体298.UnPolarized light 非极化光299.Wave 波300.Wave equation 波公式301.Wavefront 波前302.Waveguide 波导303.Wave number 波数304.Wave packet 波包络305.Wavevector 波矢量306.Dark current 暗电流307.Saturation signal 饱和信号量308.Fringing field drift 边缘电场漂移plementary color 补色310.Image lag 残像311.Charge handling capability 操作电荷量312.Luminous quantity 测光量313.Pixel signal interpolating 插值处理314.Field integration 场读出方式315.Vertical CCD 垂直CCD316.Vertical overflow drain 垂直溢出漏极317.Conduction band 导带318.Charge coupled device 电荷耦合组件319.Electronic shutter 电子快门320.Dynamic range 动态范围321.Temporal resolution 动态分辨率322.Majority carrier 多数载流子323.Amorphous silicon photoconversion layer 非晶硅存储型324.Floating diffusion amplifier 浮置扩散放大器325.Floating gate amplifier 浮置栅极放大器326.Radiant quantity 辐射剂量327.Blooming 高光溢出328.High frame rate readout mode 高速读出模式329.Interlace scan 隔行扫描330.Fixed pattern noise 固定图形噪声331.Photodiode 光电二极管332.Iconoscope 光电摄像管333.Photolelctric effect 光电效应334.Spectral response 光谱响应335.Interline transfer CCD 行间转移型CCD336.Depletion layer 耗尽层plementary metal oxide semi-conductor 互补金属氧化物半导体338.Fundamental absorption edge 基本吸收带339.Valence band 价带340.Transistor 晶体管341.Visible light 可见光342.Spatial filter 空间滤波器343.Block access 块存取344.Pupil compensation 快门校正345.Diffusion current 扩散电流346.Discrete cosine transform 离散余弦变换347.Luminance signal 高度信号348.Quantum efficiency 量子效率349.Smear 漏光350.Edge enhancement 轮廓校正351.Nyquist frequency 奈奎斯特频率352.Energy band 能带353.Bias 偏压354.Drift current 漂移电流355.Clamp 钳位356.Global exposure 全面曝光357.Progressive scan 全像素读出方式358.Full frame CCD 全帧CCD359.Defect correction 缺陷补偿360.Thermal noise 热噪声361.Weak inversion 弱反转362.Shot noise 散粒噪声363.Chrominance difference signal 色差信号364.Color temperature 色温365.Minority carrier 少数载流子366.Image stabilizer 手振校正367.Horizontal CCD 水平CCD368.Random noise 随机噪声369.Tunneling effect 隧道效应370.Image sensor 图像传感器371.Aliasing 伪信号372.Passive 无源373.Passive pixel sensor 无源像素传感器374.Line transfer 线转移375.Correlated double sampling 相关双采样376.Pinned photodiode 掩埋型光电二极管377.Overflow 溢出378.Effective pixel 有效像素379.Active pixel sensor 有源像素传感器380.Threshold voltage 阈值电压381.Source follower 源极跟随器382.Illuminance 照度383.Refraction index 折射率384.Frame integration 帧读出方式385.Frame interline transfer CCD 帧行间转移CCD 386.Frame transfer 帧转移387.Frame transfer CCD 帧转移CCD388.Non interlace 逐行扫描389.Conversion efficiency 转换效率390.Automatic gain control 自动增益控制391.Self-induced drift 自激漂移392.Minimum illumination 最低照度393.CMOS image sensor COMS图像传感器394.MOS diode MOS二极管395.MOS image sensor MOS型图像传感器396.ISO sensitivity ISO感光度。
助熔剂法生长二钛酸钡单晶
第 ６期
徐 军 ，等 ：助 熔 剂 法 生 长 二 钛 酸 钡 单 晶
５５
（１ ２２０～ｌ ２３０℃ ）Ｌ ｓＩ，因此 其 单 晶 的助 熔 剂 法 制 备 比较 困难 ．在 实验 中若 仅用 ＢａＢ ０ 做 助 熔 剂 则 只能 得 到 ＢａＴｉＯ３晶 体 ，无 ＢａＴｉ Ｏ 生 成 ．可 以 推 测 ，在 助熔 剂 法生 长 ＢａＴｉ Ｏ 晶体过 程 中添加 一 种 能 够 扩 大 ＢａＴｉ Ｏ 相 稳 定 区 的 Ｂａ Ｏ 相 稳 定 剂 将 有助 于助 熔 剂法 制备 ＢａＴｉ Ｏ 晶体 的成 功 ．最 近 有 文 献 报 道 Ｂ Ｏ，具 有 稳 定 Ｂ ｉ Ｏ 相 ，扩 大 ＢａＴｉ：Ｏ 热 力 学 稳 定 区 的作 用 Ｊ．在 本 实 验 中 ，通 过 添加 少量 Ｂ Ｏ，，以 ＢａＢ：０ 为 助熔 剂 ，成 功 地 制 备 了 ＢａＴｉ，Ｏ 单 晶 ．
采用 转靶 ｘ射 线 衍射 （ＸＲＤ）分 析 仪 （日本理 学 Ｄ／Ｍａｘ—ＲＢ）分 析 晶体 的物 相 ，利 用 双 目体 视 显微 镜 （ＪＳＺ６连 续 变倍 体 视 显 微 镜 ）观 察 晶体 的
收 稿 日期 ：２０１２—０５—１２ 基金项 目：教育 部留学 回国人员科研启动基金 ，湖北省教育厅科学研究重 点项 目（Ｄ２０１０１５０４） 作者简介 ：徐 军（１９７０一），男 ，湖北武汉人 ，教授 ，博 士．研究方 向 ：电子功能材料．
３ 结 语
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氧化锡纳米结构的制备及光致发光性能
氧化锡纳米结构的制备及光致发光性能李立珺【摘要】利用热蒸发法成功制备出了两种氧化锡纳米结构.利用X射线衍射法、拉曼光谱、扫描电子显微镜和透射电子显微镜对两种纳米结构的晶格结构和表面形貌做了详细分析,结果表明所制纳米结构为金红石型氧化锡晶体结构,氧化锡纳米结构的形貌与实验中所用的源材料有着很大的关系.以氧化锡和碳粉的混合物为源,制备出的纳米线长且直,直径在50～200nm之间,以氧化亚锡和碳粉为源,制备出的纳米结构短且多弯折,直径在150nm左右.研究了所制氧化锡纳米材料的室温光致发光性能,发光峰位于590、630和677nm处.【期刊名称】《功能材料》【年(卷),期】2013(044)009【总页数】4页(P1269-1271,1276)【关键词】氧化锡;纳米结构;热蒸发法;X射线衍射;光致发光【作者】李立珺【作者单位】西安邮电大学电子工程学院,陕西西安710121【正文语种】中文【中图分类】TB334;O782+.91 引言SnO2作为一种重要的宽禁带半导体功能材料，由于具有优异的光学、电学特性，在气敏传感器［1］、透明导电材料［2］、紫外探测器［3］、场发射器件［4］等众多领域具有广阔的潜在应用前景，引起了人们的广泛关注。
由于特殊的物理属性和在纳米级器件上的应用，近年来一维纳米结构已经引起了人们强烈的兴趣。
SnO2纳米结构的研究也取得了重大的进展。
通常制备SnO2纳米结构的方法有水热合成法［5］、化学气相沉积法［6］，激光脉冲沉积法［7］和热蒸发法［8-12］。
其中热蒸发法最为常用，该方法制备的产品纯度高，均一性好，可通过改变反应条件实现可控制性生长。
目前，已通过控制实验温度、气压、气流量、催化剂等工艺条件制备出了不同形貌的纳米结构，如纳米片［8］、纳米线［9］、纳米带［10］、之字状结构［11］及鱼骨状结构［12］等。
通过改变源材料配比，也能影响到纳米结构形貌的变化，而目前相关报道较少。
本文通过改变源材料配比，利用热蒸发法成功制备出了两种不同形貌的氧化锡纳米结构，进行了形貌和结构表征，并初步研究了所制两种氧化锡纳米结构的室温光致发光性能。
Sb2Te3基热电薄膜的研究进展
第49卷第6期2021年6月硅酸盐学报Vol. 49，No. 6June，2021 JOURNAL OF THE CHINESE CERAMIC SOCIETY DOI：10.14062/j.issn.0454-5648.20200617Sb2Te3基热电薄膜的研究进展易文1,2，赵永杰1，王伯宇1，周志方2，李亮亮2，李静波1(1. 北京理工大学材料学院, 北京 100081；2. 清华大学材料学院，北京 100084)摘要：基于热电薄膜的微型热电器件在微区制冷、温差发电等领域具有广阔应用前景。
具有高功率因子、ZT值的热电薄膜对微型热电器件的性能至关重要。
Sb2Te3基材料是室温下性能优异的p型热电材料。
然而，目前Sb2Te3基薄膜的热电性能仍然不能满足实际应用的需求。
简述了热电材料研究的相关背景，介绍了Sb2Te3的晶体结构，概述了Sb2Te3基薄膜的常用制备技术，从提高功率因子和降低热导率2方面综述了提高Sb2Te3基薄膜热电性能的方法。
重点介绍了材料组织、微观结构与热电性能的关系，即缺陷、择优取向、纳米颗粒、超晶格、有机无机杂化等对Sb2Te3基薄膜热电性能的影响。
此外，对Sb2Te3基热电薄膜的发展方向予以展望。
关键词：热电薄膜；碲化锑；热电性能；功率因子；热导率中图分类号：TB34 文献标志码：A 文章编号：0454–5648(2021)06–1111–14网络出版时间：2021-04-06Research Progress on Antimony Telluride Based Thermoelectric Thin FilmsYI Wen1,2, ZHAO Yongjie1, WANG Boyu1, ZHOU Zhifang2, Li Liangliang2, Li Jingbo1(1. School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China;2. School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China)Abstract: Micro thermoelectric devices based on thermoelectric films have promising applications in various fields such as micro-zone refrigeration and power generation. Thermoelectric films with high power factor and large ZT values are critical materials in these devices. Sb2Te3-based materials are outstanding p-type thermoelectric materials at room temperature. However, the thermoelectric properties of Sb2Te3-based thin films cannot meet the requirement of practical applications. The research background of thermoelectric materials is briefly introduced, the crystal structure of Sb2Te3 is discussed, the preparation techniques of Sb2Te3-based thin films are outlined, and the methods of improving the power factor and reducing the thermal conductivity of Sb2Te3-based thin films are summarized. In particular, the effects of microstructure on thermoelectric properties are focused on to elucidate the mechanism of improving thermoelectric properties of the films, which includes defects, preferential orientation, nanoparticles, superlattice, organic-inorganic hybridization, and so on. In addition, the future research directions for Sb2Te3-based thermoelectric thin films are discussed.Keywords:thermoelectric thin film; antimony telluride; thermoelectric property; power factor; thermal conductivity当前，能源危机、全球变暖、环境污染等问题日益严重，因此，寻找资源丰富、环境友好的新能源材料，并实现能源的高效利用至关重要[1-3]。
纳米第07讲-物理气相沉积法
纳米材料和纳米结构P hysical V apor D eposition物理气相沉积第七讲Physical Vapor Deposition (PVD)物理气相沉积一、Definition定义Film deposition by condensation(凝结) from vapor phase(气相)从气相凝结的薄膜沉积二、Three Steps of PVD：(PVD的三个步骤：)1、Generating a vapor phase by evaporation or sublimation(用蒸发或升华生成一个气相)1、Electron-beam evaporation(电子束蒸发)2、Molecular-beam epitaxy(分子束外延)3、Thermal evaporation(热蒸发)4、Sputtering (溅射)5、Cathodic arc plasma deposition(阴极电弧等离子沉积)6、Pulsed laser deposition(脉冲激光沉积)2、Transporting the material from the source to the substrate(把原材料导入基底；)3、Formation of film by nucleation and diffusion(集结和扩散作用形成薄膜；)三、Application(应用)1、Coatings of electronic materials(电子材料的镀膜)Insulator绝缘体Semiconductor半导体Conductor导体Superconductor(超导体)2、Nanometer scale multilayer structures（纳米尺寸的层结构）Advanced electronic devices先进电子设备Abrasion resistant coatings耐磨涂料四、Concerned Problems(关注问题)*Contamination at the interfaces or intermixing(在物质界面和混合下的污染情况) * Multi-material systems involved(相关的复合材质系统；)* Cost of equipment and maintenance(器材和维护费用)* Complexion of operation(运算情况)五、Systems Described in This Section(此节中描述的系统)Sputtering(溅射法)Pulsed laser deposition(脉冲激光沉积法)1 Sputtering（溅射）1-1 Principle of Sputtering(溅射原理)1-2 Sputtering System(溅射系统)1-3 Preparing Multilayer Structures by Sputtering(溅射法备制多分子层结构) 1-4 Current Status of Sputtering(溅射法的近况)1-11-1 Principle of Sputtering(溅射原理)1、Ejection of Atoms from the Target（靶物质原子的喷溅）* Accomplished by an energetic particle bombarding a target surface with sufficient energy (50 eV – 1 000 eV)（在足够电压下（大概50---1000eV）,高能量粒子撞击靶物质表面来完成喷溅。
纳米结构与纳米材料基础词汇
纳米结构与纳米材料基础词汇纳米科学技术Nano-ST自上而下top down自下而上bottom up纳米物质Nanostructured materials国家纳米技术推进计划National Nanotechnology Initiative--NNI纳米科学nanoscience纳米技术狭义的nanotechnology纳米工程nanoengineering超薄膜ultrathin films体材料bulk materials纳米技术nano scale technology纳米科学nano scale science纳米材料nanostructure materials或nanomaterials纳米结构nanostructure1.纳米材料nanomaterial2. 纳米晶或纳米相nanocrystalline or nanophase3.纳米非晶态材料nano amorphous materials4. 纳米半导体材料nano semiconductors5.纳米陶瓷材料nano ceramic materials6.纳米复相材料nanomultiphase materials7.纳米结构nanostructural8. 纳米技术nanotechnology9.纳米组装体系nanostructured assembling system10. 胶体化学colloid chemistry11.人造超原子artificial superatoms12. 原子簇cluster13.超微粒子ultra-fine particle14. 人造原子artificial atoms15.扫描隧道显微镜scanning tunneling microscope, STM 16.化学气相沉积chemical vapor deposition CVD17.激光诱导化学气相沉积laser induced chemical vapor deposition LICVD18.性质property19. 力学性质mechanical property20.光学性质optics property21. 电学性质electronics property22.磁学性质magnetic property22. 纳米结构块体nanaostructureed bulk23.纳米复合材料nano-composite materials24. 纳米簿膜材料nanofllm materials25.溶胶—凝胶法Sol-Gel26. 碳纳米管carbon nano-tube27.同轴纳米电缆coaxial nanocable28. 抗折强度flexural strength29.微观形貌microstructure30. 透射电镜TEM tunneling electric microscope31.介观固体mesoscopy solid32.气体蒸发法gas evaporation method33.气体冷凝法gas-condensatin method34. 蓝移blue shift35.红移red shift36.磁性液体magnetic fluid37.纳米生物材料nano-biomaterials38.单晶single crystal39.多晶polycrystal40. 粘度viscosity41.抗拉强度tensile strength42.抗压强度compressive strength43.晶界crystal boundary44.纳米超导体nanosuperconductor45.半导体semiconductor46.介电性能dielectric performance47.纳米器件nano-device48.纳米机器人nanorobert49.微机电系统MEMS microelectric mechanics system50.化合物compound51.电子特性electronic character52.量子点quantum dot53纳米阵列nanoarray54.表面效应surface effect55.量子尺寸效应quantum size effect56.散射dispersion57.吸收absorb58.量子理论quantum theory59.能带理论energy bind theory60.催化catalysis61.纳米结构陶瓷nano-structural ceramics62.界面boundary63. 制备方法produced method64.液相法liquid-phase method65. 固相法solid-phase method66.共沉淀法co-precipitate method67. 纤维fiber68.超细粉末ultra-fine powder69. 团聚agglomerate70.量子芯片quantum chip77. 一维one dimension78.二维two dimension79. 三维three dimension80.强度strength81. 结构陶瓷structural ceramics 82.塑性形变plastic deformation83.脆性断裂brittle fracture84.量子quantum85.机理mechanism86.功能陶瓷functional ceramics87.功能玻璃functional glass88.金属Metal89.合金Alloy90.硬度hardness91分散disperse92.表面活性剂surface activity reagent93.表面修饰surface modify94. 纳米线nano-line95. 纳米丝nano-thread96.纳米棒nano-rod97. 氢键hydrogen valent98.纳米自组装nano-self- assembling99. 结构与性能composition structure performance100.多量子阱自组装self- assembling multi-quantum-well structure纳米尺度nanoscale纳米基元nano-unit纳米结构单元nanostructure unit纳米材料nanomaterial纳米技术nanotechnology纳米结构体系nanostructure system纳米组装体nanostructure assembling system 纳米器件nanodevice碳纳米管carbon nanotubes，CNTs原子团簇atom cluster单分散颗粒[系] monodispersed particle纳米颗粒nanoparticle团粒aggregate纳米粉体nano-powder纳米纤维nano-fibre纳米薄膜nano-film纳米块体nano-bulk纳米孔nano-pore纳米晶体材料nanocrystalline material 纳米非晶材料amorphous nanomaterial纳米准晶材料quasi-crystal nanomaterial金属纳米材料metallic nanomaterial无机非金属纳米材料inorganic non-metallic nanomaterial高分子纳米材料polymer nanomaterial纳米复合材料nanocomposites结构纳米材料structured nanomaterial功能纳米材料functional nanomaterial生物医用纳米材料biomedical nanomaterial 小尺寸效应small-size effect表面效应surface effect量子尺寸效应quantum size effect宏观量子隧道效应macroscopic quantum tunneling effect，MQT惰性气体沉积法inert gas deposition物理粉碎法physics grinding高能球磨法high energy ball mill溅射法sputtering物理粉碎法physics grinding 爆炸法explosion 喷雾法spraying冷冻干燥法freeze drying化学气相沉积法chemical vapor deposition，CVD沉淀法precipitation水热合成法hydrothermal synthesis溶胶-凝胶法sol－gel辐射化学合成法radiation chemical synthesis快速凝固法rapidly quenching强烈塑性变形法severe(intense) plastic deformation非晶晶化法amorphous solid crystallization 溅射法sputtering非晶晶化法crystallization of amorphous solid原位复合法in-situ composite插层复合法intercalation hybrids微乳液法micro emulsion模板合成法template synthesis自组装法self-assembly石墨电弧放电法graphite arc discharge快速凝固法rapidly quenching表面处理surface treatment表面修饰surface decoration稳定化处理passivating treatmentX射线衍射法X-ray diffractometry ，XRD扫描探针显微镜scanning probe microscopy, SPM扫描隧道显微镜scanning tunneling microscopy, STM扫描近场光学显微镜scanning near-field optical microscopy, SNOM原子力显微镜atomic force microscopy, AFM 扫描电容显微镜scanning capacitance microscopy, SCM磁力显微镜magnetic force microscopy, MFM扫描热显微镜scanning thermal microscopy, STHMX射线衍射法X-ray diffractometry ，XRDX射线衍射线宽化法X-ray diffractometry line broadening, XRD-LBX射线小角度散射法small angle X-ray scattering, SAXS透射电子显微镜法transmission electron microscopy ,TEM 透射电镜法TEM method扫描电子显微镜法scanning electron microscopy , SEM扫描电镜法SEM method拉曼光谱法raman spectrometry红外吸收光谱法infrared absorption spectroscopy穆斯堡尔谱法mossbauer spectrometry光子相关谱法photon correlation spectroscopyBET法BET压汞仪法mercury porosimetry纳米压痕仪nano impress,NI4.6.16扫描探针显微法scanning probe microscopy, SPM扫描隧道电子显微法scanning tunneling electron microscopy,STM扫描近场光学显微法scanning near-field optical microscopy，SNOM原子力显微法atomic force microscopy，AFM扫描电容显微法scanning capacitance microscopy, SCM扫描热显微法scanning thermal microscopy, STHM场离子显微法field ion microscopy, FIM磁力显微法magnetic force microscopy, MFM激光干涉仪laser interferometer激光衍射/散射法laser diffraction and scattering离心沉降法centrifugal sedimentation。
庞磁电阻效应和强关联电子
（计算另讲）
Mn3+和Mn4＋ 1，电荷棋盘 2，自旋zigzag 3，轨道转向，
38
电荷、自旋、轨道有序（6）
小结：形成电荷、自旋和轨道有序的原因？ 1，电荷有序： 势能大于动能 U 》t ， 例如，一个格点只能有一个 eg 电子。 2，轨道有序：畸变能大于动能 g 》t。 例如，eg、 t2g 电子的轨道要对于 J－T 晶格畸变 方向取向。 3，自旋有序 （接下一页）
2
对CMR的兴趣何在？
强关联电子理论 超越“传统的能带理论” 课题：Mott绝缘体、 Wigner 电子晶体、高温超导、庞磁电阻、 重费米子、巡游电子等 注意，各种磁电阻（MR）现象受到关注，但物理机制不同： AMR,GMR,TMR －－－能带论框架内“自旋极化电子散射过程” CMR －－－非能带理论的“强关联电子跃迁过程”
为甚麽同时有序？
超交换作用： 轨道排布不同 ， → 波函数重叠不同 → 自旋排列也不同
34
*电荷、自旋、轨道有序（2）
LaMnO3 的反铁磁？
Mn3＋离子自旋排列为AFM。 原因：同一格座上 eg与t2g的洪德FM耦合。 相邻格座超交换AFM作用
实际的轨道波函数的情况稍微复杂， Jahn－Teller 效应（电声子作用）
La1 x Srx MnO3
当x＝0 和1， 为 反铁磁性、绝缘体 当0。2 < x < 0。4， 为 铁磁性、金属
8
三种反铁磁氧化物的“掺杂”
原型化合物电价和轨道L源自2CuO4Cu2＋， 3d9
LaMnO3
Mn3＋， 3d4
LaTiO3
Ti3＋，3d1
“单”电子态 1个空穴
磁性 掺杂化合物 磁性 电性 电子有序 AFM High Tc 非磁 超导 电子条纹相
光电子单词表 中英对照
1. semiconductor: 半导体，常温下导电性能介于导体(conductor)与绝缘体(insulator)之间的材料。
2. light-emitting diode (LED): 发光二极管3. laser diode (LD): 半导体激光器4. photodiode: 光电二极管5. electrons: 电子6. holes: 空穴7. energy gap: 能隙8. photon: 光子9. insulator: 绝缘体10. transistor: 晶体管11. solar cell: 太阳能电池12. quantum dot: 量子点13. doping: 掺杂。
14. Pauli exclusion principle: 泡利不相容原理。
15. Fermi level: 费米能级16. valence band: 价带17. conduction band: 导带18. optical fiber: 光纤19. energy level: 能级。
20. electron–hole pair: 电子-空穴对。
21. impurity: 杂质。
22. dopant: 掺杂剂。
23. intrinsic (pure) semiconductor: 纯半导体。
24. p-type semiconductor: P 型半导体25. n-type semiconductor: N 型半导体。
26. p–n junction: PN 结27. space charge region(depletion layer): 空间电荷区(耗尽层)。
28. forward-bias voltage: 正向偏置电压29. ground state: 基态30. upper level: 上能级31. lower level: 下能级33. electromagnetic radiation:电磁辐射。
材料类专业词汇
专业词汇A奥氏体austenite 奥氏体本质晶粒度austenite inhorent grain size 奥氏体化austenitization, austenitii zingB白口铸铁white cast iron白铜white brass, copper-nickel alloy板条马氏体lath martensite棒材bar包晶反应peritectic reaction薄板thin sheet薄膜技术thin film technique贝氏体bainite本质晶粒度inherent grain size比强度strength-to-weight ratic变质处理inoculation, modification变质剂modifying agent,modificator表面处理surface treatment表面粗糙度surface roughness表面淬火surface quenching表面腐蚀surface corrosion表面硬化surface hardening玻璃glass玻璃态vitreous state, glass state玻璃钢glass fiber reinforced plastics玻璃纤维glass fiber不可热处理的non-heat-treatable不锈钢stainless steel布氏硬度Brinell hardnessC材料强度strength ofmaterial残余奥氏体residual austenite残余变形residual deformation残余应力residual stress层状珠光体lamellar pearlite超导金属superconducting metal成核nucleate, nucleation成形forming, shaping成长growth, growing磁材料magnetic materials冲击韧性impact toughness纯铁pure iron粗晶粒coarse grain脆性brittleness脆性断裂brittle fracture淬火quenching, quench淬透性hardenability淬硬性hardenabilityD带材baud, strip单晶single crystal, unit crystal单体monomer, element氮化层nitration case氮化物nitride刀具cutting tool导磁性magnetic conductivity导电性electric conductivity导热性heat conductivity, thermal conductivity导体conductor等离子堆焊plasma surfacing等离子弧喷涂plasma spraying等离子增强化学气相沉积Plasma chemical vapour deposition (PCVD) 等温转变曲线isothermal transformation curve低合金钢low alloy steel低碳钢low carbon steel低碳马氏体low carbon?martensite低温回火low tempering点阵常数grating constant, lattice constant电镀electroplating, galvanize电弧喷涂electric arc spraying电子显微镜electron microscope定向结晶directional solidification S端淬试验end quenching test断口分析fracture analysis断裂强度breaking strength, fracture strength断裂韧性fracture toughness断面收缩率contraction of cross sectional area,锻造forge, forging, smithing多晶体polycrystalE二次硬化secondaryhardening二元合金binary alloy, two-component alloyF防锈的rust-proot, rust resistant非金属non-metal, nonmetal非晶态amorphous stats分子键molecular bond分子结构molecular structure分子量molecular weight酚醛树脂bakelite, phenolic resin粉末治金powder metallurgy粉末复合材料particulate composite腐蚀corrosion, corrode, etch, etching腐蚀剂corrodent, corrosive, etchant复合材料composite materialG感应淬火inductionquenching刚度rigidity, stiffness钢steel钢板steel plate钢棒steel bar钢锭steel ingot钢管steel tube, steel pipe钢丝steel wire钢球steel ball杠杆定理lever rule, lever principle高分子聚合物high polymer, superpolymer 高合金钢high alloy steel高锰钢high manganess steel高频淬火high frequency quenching高速钢high speed steel ,quick-cutting steel 高碳钢high-carbon steel高碳马氏体high carbon martensite高弹态elastomer高温回火high tempering各向同性isotropy各向异性anisotropy, anisotropism工程材料engineering material工具钢tool steel工业纯铁industrial pure iron工艺technology共价键covalent bond共晶体eutectic共晶反应eutectic reaction共析体eutectoid共析钢eatectoid steel功能材料functional materials固溶处理solid solution treatment固溶强化solution strengthening固溶体solid solution固相solid phase光亮热处理bright heat treatment滚珠轴承钢ball bearing steel过饱和固溶体supersaturated solid solution过共晶合金hypereutectic alloy过共析钢hypereutectoid steel过冷over-cooling, supercooling过冷奥氏体supercooled austenite过冷度degree of supercooling过热overheat, superheatH焊接welding, weld航空材料aerial material合成纤维synthetic fiber合金钢alloy steel合金化alloying合金结构钢structural alloy steel黑色金属ferrous metal红硬性red hardness滑移slip, glide滑移方向glide direction, slip direction滑移面glide plane, slip plane滑移系slip system化合物compound化学气相沉积chemical vapour eposition (CVD) 化学热处理chemical heat treatmentJ基体matrix机械混合物mechanical mixture机械性能mechanical property激光热处理heat treatment with a laser beam 激光laser激光熔凝laser melting and consolidation激光表面硬化surface hardening by laser beam 加工硬化work hardening加热heating胶粘剂adhesive结构材料structural material结晶crystallize, crystallization结晶度crystallinity金属材料metal material金属化合物metallic compound金属键metallic bond金属组织metal structure金属结构metallic framework金属塑料复合材料plastimets金属塑性加工metal plastic?working金属陶瓷metal ceramic金相显微镜metallographic microscope, metalloscope金相照片metallograph晶胞cell晶格crystal lattice晶格常数lattice constant晶格空位lattice vacancy晶粒crystal grain晶粒度grain size晶粒细化grain refining晶体结构crystal structure聚四氟乙烯polytetrafluoroethy lene (PTFE)聚合度degree of polymerization聚合反应polymerization绝热材料heat-insulating material绝缘材料insulating materialK抗拉强度tensile strength抗压强度compression strength颗粒复合材料particle composite扩散diffusion, diffuseL老化aging莱氏体ledeburite冷变形cold deformation冷加工cold work, cold working冷却cool, cooling冷作硬化cold hardening离子ion粒状珠光体granular pearlite连续转变曲线continuous cooling transformation(CCT) curve 孪晶twin crystal孪生twinning, twin螺旋位错helical dislocation洛氏硬度Rockwell hardnessM马氏体martensite (M)密排六方晶格close-packed xagonal lattice (C.P.H.)面心立方晶格face-centred cubic lattice (F.C.C.)摩擦friction磨损wear, abrade, abrasion模具钢die steelMf 点martensite finishing pointMs点martensite starting pointN纳米材料nanostructuredmaterials耐磨钢wear-resisting steel耐磨性wearability, wear resistance耐热钢heat resistant steel , high temperature steel内耗internal friction内应力internal stress尼龙nylon粘弹性viscoelasticity凝固solidify, solidification扭转强度torsional strength扭转疲劳强度torsional fatigue strengthP泡沫塑料foamplastics, expanded plastics配位数coordination number喷丸硬化shot-peening疲劳强度fatigue strength疲劳寿命fatigue life片状马氏体lamellar martensite, plate type martensite普通碳钢ordinary steel, plain carbon steelQ气体渗碳gas carburizing切变shear切削cut, cutting切应力shearing stress球化退火spheroidizing annealing球墨铸铁nodular graphite cast iron, spheroidal graphitecast iron 球状珠光体globular pearlite屈服强度yielding strength, yield strength屈强比yielding-to-tensile ratio屈氏体troolstite (T)去应力退火relief annealingR热处理heat treatment热加工hot work, hot working热喷涂thermal spraying热固性thermosetting热塑性hot plasticity热硬性thermohardening柔顺性flexibility人工时效artificial ageing刃具cutting tool刃型位错edge dislacation, blade dislocation韧性toughness溶质solute溶剂solvent蠕变creep蠕墨铸铁quasiflake graphite cast iron软氮化soft nitridingS扫描电镜scanning electronmicroscope (SEM)上贝氏体upper bainite渗氮nitriding渗硫sulfurizing渗碳carburizing, carburization渗碳体cementite (Cm)失效failure石墨graphite (G)时间-温度转变曲线time temperature transformation (TTT) curve 时效硬化age-hardening实际晶粒度actual grain size使用寿命service life使用性能usability树枝状晶dendrite树脂resin双金属bimetal, duplex metal水淬water quenching, water hardening, water quench松弛relax , relaxation塑料plastics塑性plasticity, ductility塑性变形plastic deformation索氏体sorbite (S)T弹簧钢spring steel弹性elasticity, spring弹性变形elastic deformation弹性极限elastic limit弹性模量elastic modulus碳素钢carbon steel碳含量carbon content碳化物carbide碳素工具钢carbon tool steel陶瓷ceramic陶瓷材料ceramic material体心立方晶格body-centered cubic lattice (B.C. C.)体型聚合物three-dimensional polymer调质处理quenching and tempering调质钢quenched and tempered steel铁碳平衡图iron-carbon equilibrium diagram透明(结晶)陶瓷crystalline ceramics同素异构转变allotropic transformation涂层coat, coating退火anneal, annealing托氏体troostite (T)W弯曲bend, bending完全退火full annealing微观组织microstructure维氏硬度Vickers hardness未经变质处理的uninoculated温度temperature无定形的amorphous物理气相沉积physical vapour deposition (PVD)X下贝氏体lower bainite线型聚合物linear polymer纤维fibre, fiber纤维增强复合材料filament reinforced composite显微照片metallograph,microphotograph, micrograph 显微组织microscopic structure, microstructure橡胶rubber相phase相变phase transition相图phase diagram消除应力退火stress relief annealing形状记忆合金Shape memory alloys形变deformation性能performance, propertyX射线结构分析X-ray structural analysisY压力加工press work亚共晶铸铁hypoeutectic cast iron亚共析钢hypoeutectoid steel氧化物陶瓷oxide ceramics延伸率elongation percentage盐溶淬火salt both quenching液相liquid phase应变strain应力stress应力场强度因子stress intensity factror应力松弛relaxation of stress硬质合金carbide alloy, hard alloy油淬oil quenching, oil hardening有机玻璃methyl-methacrylate, plexiglass 有色金属nonferrous metal匀晶uniform grain孕育处理inoculation, modificationZ再结晶退火recrystallization annealing载荷load增强塑料reinforced plastics针状马氏体acicular martensite正火normalize, normalization致密度tightness支化型聚合物branched polymer智能材料intelligent materials中合金钢medium alloy steel轴承钢bearing steel轴承合金bearing alloy珠光体pearlite (P)柱状晶体columnar crystal铸造cast , foundry自然时效natural ageing自由能free energy组元component, constituent组织structureα钛合金αtitanium alloy。
张利强 - 中国石油大学
张利强中国石油大学（北京），理学院材料科学与工程系，助理研究员张利强，男，助理研究员。
2012年6月入选中国石油大学（北京）青年拔尖人才，并于2012年7月入职中国石油大学（北京）。
在2009年底，申请人得到国家留学基金委全额资助到美国进行为期两年的联合培养，师从世界著名材料学家匹兹堡大学Scott X Mao教授与美国桑迪亚国家实验室黄建宇研究员。
研究课题为新型能源材料的设计与改性。
在美国桑迪亚国家实验室期间，在黄建宇研究员的指导下使用透射电镜在2010年底合作制备出迄今为止世界上最小的电池，其成果发表在世界顶级杂志《Science》上，受到世界同行的关注，并被美国多家电视台报道，并被百度、新浪等门户网站评选为2010年世界七大科技之最之一。
近三年来，申请人在Science(IF=31.201)，Nano.Lett.(IF=13.19)，ACS nano(IF=10.77)等杂志，以合作作者和第一作者共发表论文23篇，他引200余次，累计影响因子111，并申请8项发明专利。
受教育经历（从大学本科开始，按时间倒排序）2010/01 – 2011/12，美国Sandia国家实验室，联合培养2009/12 – 2011/12，美国匹兹堡大学，材料系，联合培养2007/09 – 2012/06，浙江大学，材料系，博士2003/09 – 2007/06，东北大学，理学院材料物理系，学士研究工作经历（按时间倒排序）2012/07 – 至今，中国石油大学（北京），理学院材料系，助理研究员主要论著（近3年来已发表的与本项目有关的主要论著目录和获得学术奖励情况）1、期刊论文：[1]L.Q. Zhang, Z.Z. Ye, B. Lu, J.G. Lu, J.Y. Huang, Y.Z. Zhang, and Z Xie, Defect-inducedferromagnetism in insulating Mn–P codoped ZnO grown in oxygen-rich environment Thin Solid Films, 155 (2013) 16.[2]L.Q. Zhang, B. Lu, Y. H. Lu, Z. Z. Ye, J. G. Lu, X. H. Pan, and J. Y. Huang, Non-polarp-type Zn0.94Mn0.05Na0.01O texture: growth mechanism and codoping effect, J. Appl. Phys., 113 (2013) 083513.[3]L.Q. Zhang, X.H. Liu, Y.-C. Perng, J. Cho, J.P. Chang, S.X. Mao, Z.Z. Ye, and J.Y. Huang,Direct observation of Sn crystal growth during the lithiation and delithiation processes of SnO2 nanowires,Micron, 43 (2012) 1127.[4]L.Q. Zhang, Y.Z. Zhang, Z.Z. Ye, J.G. Lu, B. Lu, B. He, The effects of group-I elementsco-doping with Mn in ZnO dilute magnetic semiconductor, J. Appl. Phys.,111 (2012) 123524.[5]L.Q. Zhang, X.H. Liu, Y. Liu, S. Huang, T. Zhu, L.J. Gui, S.X. Mao, Z.Z. Ye, C. M. Wang, J.P. Sullivan, J.Y. Huang, Controlling the Lithiation-Induced Strain and Charging Rate in Nanowire Electrodes by Coating, ACS Nano, 5 (2011) 4800-4809.[6]L.Q. Zhang, Z.Z. Ye, J.Y. Huang, B. Lu, H.P. He, J.G. Lu, Y.Z. Zhang, J. Jiang, J. Zhang,K.W. Wu, W.G. Zhang, Fabrication and properties of p-type K doped Zn1-x Mg x O thin film, J.Alloys Compd.,509 (2011) 7405-7409.[7]L.Q. Zhang, Z.Z. Ye, B. Lu, J.G. Lu, Y.Z. Zhang, L.P. Zhu, J.Y. Huang, W.G. Zhang, J.Huang, J. Zhang, J. Jiang, K.W. Wu, Z. Xie, Ferromagnetism induced by donor-related defects in Co-doped ZnO thin films, J. Alloys Compd.,509 (2011) 2149-2153[8]L.Q. Zhang, Z.Z. Ye, B. Lu, J.G. Lu, Y.Z. Zhang, L.P. Zhu, J. Zhang, J. Jiang, K.W. Wu, B.He, Fabrication and properties of Li-doped ZnCoO diluted magnetic semiconductor thin films. Superlattices Microstruct.,50 (2011) 261-268[9]L.Q. Zhang, Z.Z. Ye, S.S. Lin, Y.Z. Zhang, B. Lu, H. P. He, L. X. Chen, J. G. Lu, J. Jiang,K.W. Wu, J.Y. Huang, L. P. Zhu, The fabrication of Na doped p-type Zn1−x Mg x O films by pulsed laser deposition, Appl. Phys. A, 106 (2011) 191-196[10]L.Q. Zhang, Z.Z. Ye, J.G. Lu, B. Lu, Y.Z. Zhang, L.P. Zhu, J. Zhang, D. Yang, K.W. Wu, J.Huang, Z. Xie, Influence of p-type and n-type dopants on the magnetic properties of ZnCuO based diluted magnetic semiconductor thin films,J. Phys. D: Appl. Phys.,43 (2010) 015001.[11]H.W. Huang, L.Q. Zhang, W.K. Wu, Q. Yu, R. Chen, H.S. Yang, X.S. Peng, Z.Z. Ye,Hetero-metal cation control of CuO nanostructures and their high catalytic performance for CO oxidation Nanoscale, 24 (2012) 7832-7841[12]Lu B, L.Q. Zhang, Y.H. Lu, Z.Z. Ye, J.G. Lu, X.H. Pan, J.Y. Huang, Ferromagneticenhancement and magnetic anisotropy in nonpolar-oriented (Mn, Na)-codoped ZnO thin films. Appl. Phys. Lett.,101 (2012) 083513.[13]X.H. Liu, L.Q. Zhang, L. Zhong, Y. Liu, H. Zheng, J.W. Wang, J.-H. Cho, S.A. Dayeh, S.T.Picraux, J.P. Sullivan, S.X. Mao, Z.Z. Ye, J.Y. Huang, Ultrafast Electrochemical Lithiation of Individual Si Nanowire Anodes,Nano Lett., 11 (2011) 2251-2258[14]X.H. Liu, L. Zhong, L.Q. Zhang, A. Kushima, S. X. Mao, J. Li, Z.Z.Ye, J.P. Sullivan, J.Y.Huang, Lithium fiber growth on the anode in a nanowire lithium ion battery during charging, Appl. Phys. Lett., 98 (2011) 183107[15]X.T. Wang, L.P. Zhu, L.Q. Zhang, J. Jiang, Z.G. Yang, Z.Z. Ye, B. He, Properties of Nidoped and Ni–Ga co-doped ZnO thin films prepared by pulsed laser deposition J. Alloys Compd.,509 (2011) 3282 -3285.[16]W.G. Zhang, Bin Lu, L.Q. Zhang, J.G. Lu, M. Fang, K.W. Wu, B.H. Zhao, Z.Z. Ye, Influenceof preparation condition and doping concentration of Fe-doped ZnO thin films: Oxygen-vacancy related room temperature ferromagnetism, Thin Solid Films, 519 (2011) 6624-6628.[17]H.W. Huang, Q. Yu, Y.H. Ye, P. Wang, L.Q. Zhang, M.X. Gao, X.S. Peng, Z.Z. Ye, Thincopper oxide nanowires/carbon nanotubes interpenetrating networks for lithium ion batteries Crystengcomm, 14:21(2012) 7294-7300[18]J.Y. Huang, L. Zhong, C.M. Wang, J.P. Sullivan, W. Xu, L.Q. Zhang, S.X. Mao, N.S. Hudak,X.H. Liu, A. Subramanian, H.Y. Fan, L. Qi, A. Kushima, J. Li,In Situ Observation of theElectrochemical Lithiation of a Single SnO2Nanowire Electrode,Science, 330 (2010) 1515-1520[19]X.H. Liu, H. Zheng, L. Zhong, S. Huang, K. Karki, L.Q. Zhang, Y. Liu, A. Kushima, W.T.Liang, J.W. Wang, J.-H. Cho, E. Epstein, S.A. Dayeh, S.T. Picraux, T. Zhu, J. Li, J.P. Sullivan, J. Cumings, C. Wang, S.X. Mao, Z.Z. Ye, S. Zhang, J.Y. Huang, Anisotropic Swelling and Fracture of Silicon Nanowires during Lithiation, Nano Lett.,11 (2011) 3312-3318.[20]W.G. Zhang, Bin Lu, L.Q. Zhang, Y.H. Ye, and Z.Z. Ye, Growth Orientation and Propertiesof ZnCoO Thin Films,J. Mater. Sci. Eng.,29 (2011) 679-683.[21]H.P. He, S.S. Lin, G.D. Yuan, L.Q. Zhang, W.F. Zhang, L.B. Luo, Y.L. Cao, Zhizhen Ye, andS.-T. Lee, Single-Crystalline Sodium-Doped p-Type ZnO and ZnMgO Nanowires via Combination of Thin-Film and Nano Techniques, J. Phys. Chem. C, 115 (2011) 19018-19022.[22]J. Jiang, X.T. Wang, L.P. Zhu, L.Q. Zhang, Z.G. Yang, and Z.Z. Ye,Electrical and magneticproperties of ZnNiO thin films deposited by pulse laser deposition.J. Zhejiang Uni-Sci A (Appl Phys & Eng),12 (2011) 561-566.[23]J. Jiang, L.P. Zhu, H.P. He, Y. Li, Y.M. Guo, L. Cao, Y.G. Li, K.W. Wu, L.Q. Zhang, and Z.Z.Ye, Structural and optical properties of ZnCdO/ZnO multiple quantum wells grown on sapphire substrates using pulsed laser deposition, J. Appl. Phys.,112 (2012) 083513.2、会议论文：[1]L.Q. Zhang, X.H. Liu, Y. Liu, S. Huang, T. Zhu, L.J. Gui, S. X. Mao, Z. Z. Ye, C. M. Wang, J. P. Sullivan, J. Y. Huang, Controlling the Lithiation Induced Strain and Charging Rate in Nanowire Electrodes by Coating,2012 TMS symposium on Mechanical Behavior at Nanoscale. Orlando, FL, USA. 2012.03.15. Poster.3、专著：[1] 叶志镇,吕建国,张银珠,何海平,马全宝,张利强等,《氧化锌掺杂与制备方法》第六章ZnO基稀磁半导体, 浙江大学出版社, 25.7万字, 20094、专利：[1]叶志镇,张利强,张银珠,吕建国,何海平,朱丽萍,Co-Ga共掺的ZnO基稀磁半导体薄膜及其制备方法, 中国, 申请号: 200910095453.6[2]叶志镇,张利强,黄靖云,张银珠,朱丽萍,汪雷,蒋杰,薛雅,张俊,一种Mg-Na共掺的ZnO基发光二极管及其制备方法, 中国, 申请号: 200910100826.4[3]叶志镇,张利强,黄靖云,张银珠,一种垂直结构ZnO基多量子阱发光二极管及其制备方法, 中国, 申请号: 200910100985.4[4]叶志镇,张利强,蒋杰,黄靖云,张银珠,张维广,张俊,朱丽萍,一种Mg-K共掺的ZnO基发光二极管及其制备方法, 中国, 申请号: 201010220372.7[5]叶志镇,张利强,吕建国,何海平,朱丽萍,张银珠,一种非极性ZnO晶体薄膜的生长方法, 授权时间: 2010.8.25, 中国, 授权号: ZL200810164207.7[6]崔立山,张利强,邵阳,姜大强,杨峰,杜敏疏,郭云鹏,郭方敏,一种应用形状记忆合金赋予薄膜大弹性应变的方法, 中国, 申请号: 201310001136.X[7]张利强,崔立山,邵阳,姜大强,杨峰,杜敏疏,郭云鹏,郭方敏,利用形状记忆合金表面浮凸实现薄膜拉伸弹性应变的方法, 中国, 申请号: 201310000764.6[8]张利强,崔立山,张俊松,姜大强,邵阳,郭云鹏,一种形状记忆合金复合材料制成的锂离子电池及制备方法, 中国, 申请号: 201210448229.2。
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Acta mater.49(2001)1051–1062/locate/actamatSINGLE-CRYSTAL LASER DEPOSITION OF SUPERALLOYS:PROCESSING–MICROSTRUCTURE MAPSM.GA ¨UMANN§,C.BEZENC ¸ON,P.CANALIS and W.KURZ†Department of Materials,Swiss Federal Institute of Technology Lausanne,1015Lausanne EPFL,Switzerland(Received 29September 2000;accepted 27October 2000)Abstract —In order to extend the life cycle of modern single-crystal (SX)high-pressure high-temperature gas turbine blades,repair of cracked or worn parts is of great interest.The success of the repair technique depends critically on a close process control in order to ensure SX repair.Based on solidification theory a process called epitaxial laser metal forming (E-LMF)has been developed.This paper presents the important concepts necessary for any process control for SX repair based on processing maps which relate the expected solidification microstructures and growth morphologies to the processing conditions.These maps are obtained in two steps.Firstly,the relationships between local solidification conditions and the resulting solidification microstructures,i.e.columnar or equiaxed,are formulated.Secondly,the local solidification conditions as a function of the laser processing parameters are calculated with an analytical heat flux model.By a combination of both approaches,processing–microstructure maps are obtained which define processing windows for SX generation and repair by laser deposition.©2001Acta Materialia Inc.Published by Elsevier Science Ltd.All rights reserved.Re´sume ´—La re ´paration locale d’aubes monocristallines (SX)de turbines a `gaz,apportant la possibilite ´d’aug-menter le cycle de vie de ces e´le ´ments,est de grand inte ´re ˆt.Afin de garantir une re ´paration monocristalline des parties endommage ´es,un proce ´de ´permettant le contro ˆle des microstructures de solidification est ne ´ces-saire.Un tel proce´de ´,epitaxial laser metal forming (E-LMF),a e ´te ´de ´veloppe ´sur la base de the ´ories de solidification.Cet article pre´sente les concepts importants pour le contro ˆle de la microstructure lors de de ´po-sition par laser,et propose des cartes de proce´de ´,reliant la microstructure de solidification et la morphologie de croissance aux parame`tres du proce ´de ´.Ces cartes sont obtenues en deux e ´tapes.Premie `rement,la relation entre les conditions locales de solidification et la microstructure de solidification re´sultante,i.e.colonnaire ou e´quiaxe,est e ´tablie.Deuxie `mement,les conditions locales de solidification sont calcule ´es en fonction des parame`tres de proce ´de ´laser,par un mode `le analytique de flux de combinaison des deux approches donne des cartes de microstructure/proce´de ´,permettant l’e ´tablissement de fene ˆtres de proce ´de ´pour une re ´par-ation monocristalline,par rechargement laser.©2001Acta Materialia Inc.Published by Elsevier Science Ltd.All rights reserved.Zusammenfassung —Die Einkristallreparatur von defekten Einkristall-Turbinenschaufeln kann zu einer betra ¨chtlichen Erho ¨hung der Lebensdauer fu ¨hren.Der Erfolg der Reparatur ha¨ngt kritisch von der Prozesskon-trolle ab,durch die das Einkristallgefu ¨ge wiederhergestellt wird.Aufgrund von erstarrungstheoretischen U ¨ber-legungen wurde ein Prozess entwickelt,der Epitaxiales Laser Metall Formen (E-LMF)genannt wird.Fu ¨r dieses Verfahren werden Prozesskarten in zwei Stufen ermittelt:(1)Beziehung zwischen den lokalen Erstar-rungsbedingungen (G ,V )und den Gefu ¨gen (gerichtet/globulitisch);(2)Beziehung zwischen lokalen Erstar-rungsbedingungen und Laserprozessparametern.Durch Kombination beider Beziehungen konnten Prozess–Gefu ¨ge-Karten aufgestellt werden,die es erlauben,eine Einkristallreparatur hoher Qualita¨t zu realisieren.©2001Acta Materialia Inc.Published by Elsevier Science Ltd.All rights reserved.Keywords:Ni alloy;Single crystal;Solidification;Laser treatment1.INTRODUCTIONOne way to raise the overall efficiency of a gas-tur-bine is to increase the operating temperature.In mod-†To whom all correspondence should be addressed.Fax:ϩ41-21-693-5890.E-mail address:wilfried.kurz@epfl.ch (W.Kurz)§Presently with Calcom SA,1015Lausanne,Switzer-land.1359-6454/01/$20.00©2001Acta Materialia Inc.Published by Elsevier Science Ltd.All rights reserved.PII:S 1359-6454(00)00367-0ern aircraft engines and power generating systems this is obtained by the use of single-crystal (SX)high pressure–high temperature (HPT)turbine blades and vanes [1,2].The life of these high value components is limited by defects such as platform cracks or blade tip erosion.A repair/reshaping technique is therefore of great economic interest in order to extend the life cycle of these components.As the SX alloys do not contain grain boundary strengtheners,it is necessary1052GA¨UMANN et al .:SINGLE-CRYSTAL LASER DEPOSITION OF SUPERALLOYS that the reshaping technique also generates a singlecrystal and a deposit which is epitactic with the sub-strate.Laser metal forming (LMF),a rapid prototyping technique related to cladding,has been developed in recent years to produce shaped components [3].Simi-lar processes with various names have been developed by other groups (for example,[4–6]).In this process,metal powder is injected into a molten pool formed by controlled laser heating of the sub-strate [Fig.1(a)].By the superposition of laser traces,a three-dimensional object can be formed which has,under controlled conditions,a reasonably good sur-face quality.The local solidification conditions which are encountered during LMF and also in the related process of laser surface remelting [Fig.1(b)]lead generally to a dendritic microstructure with columnar or equiaxed growth morphology.Epitaxial laser metal forming (E-LMF)[7]is a LMF-type process where epitaxial growth of colum-nar dendrites is achieved during the solidificationofFig.1.Schematic representation of (a)the LMF process (first two deposits only are shown)and (b)the laser surface remelt-ing process.the melt pool by a careful selection of the processing parameters through (i)partial remelting of the sub-strate to ensure epitaxy between substrate and deposit [Fig.2(a)],and (ii)avoiding the CET (columnar to equiaxed transition),i.e.nucleation and growth of equiaxed grains [Fig.2(b)].A close process control based on recent solidification theory (e.g.[8])is a prerequisite for any successful SX repair.In this way the crystal orientation of the substrate is reproduced in the newly formed solid which shows,due to higher solidification rates,a finer columnar dendritic struc-ture.With this process,SX repair has been performed locally on damaged turbine blades [9].Single crystal-line solidification was also obtained in electron beam and pulsed laser welds of Fe–Cr–Ni alloys and Ni-base superalloys when the substrate was itself a single crystal [10–12].The aim of this paper is to present the basic con-cepts for the determination of relevant laser pro-cessing windows for a controlled SX repair of SX turbine components.After describing the experi-mental conditions,a microstructure selection criterion for the CET of complex alloys is developed and a microstructure selection map for the superalloy CMSX-4is established.The local solidification con-ditions (thermal gradient,G ,and solidification velo-city,V )during the laser process are calculated.The influence of the processing parameters such as laser power,P ,beam velocity,V b ,beam diameter,D b ,orFig.2.Schematic representation showing (a)fine epitaxial col-umnar dendritic growth on a SX substrate with coarse den-drites,(b)defects to be avoided in E-LMF:loss of epitaxy and columnar to equiaxed transition (CET).The lines represent aspecific crystal orientation such as [001].1053GA¨UMANN et al .:SINGLE-CRYSTAL LASER DEPOSITION OF SUPERALLOYS Table 1.Nominal composition,in wt%,of SX alloys,CMSX-4and PWA 1480[15]CoCr Al Ti W Ta Re Mo Hf Ni CMSX-49.0 6.5 5.6 1.0 6.0 6.5 3.00.60.1bal.PWA 14805105.01.5412–––bal.preheating temperature,T 0,on the solidification microstructures is shown in the form of processing–microstructure maps.Such maps are instrumental for the control and optimisation of the E-LMF process.2.EXPERIMENTALLaser metal forming and laser remelting (Fig.1)are related localised solidification processes.The lat-ter may be seen as LMF with a powder feed rate equal to zero [13].Laser remelting represents a simpler form of the more complex LMF process and allows rapid analytical calculation of the local solidification ser remelting is therefore used here for the modelling of the solidification phenomena of the E-LMF process and to connect the processing para-meters with the relevant parameters for microstruc-ture control.Substrates for laser remelting experiments were machined from single crystalline cast ingots,fully heat treated (solutionized and aged [14])with the Ͻ001>orientation normal to the surface.The alloy CMSX-4(Table 1),a typical commercial SX Ni-base superalloy,was selected for the experiments.For all experiments a 1.7kW cw CO 2laser was used.The beam intensity profile was a near top hat mode (TEM 00ϩTEM 01)with circular polarisation.Six surface remelting experiments of SX substrates were undertaken under different processing para-meters (Table 2).Three conditions (samples A–C)will be discussed in more detail.Preheating was done with an induction coil.In all experiments a laminar flow of Ar was applied for oxidation protection of the melt pool.The shape and microstructure of the laser trace was observed with optical and electronic micro-scopes.Sections were polished with diamond paste and an acidic alumina suspension was used for final polishing.The volume fraction f of equiaxed grains after laser resolidification is obtained by electron back scattering diffraction (EBSD)analysis of transverseTable 2.Processing parameters (preheating temperature,T 0,laser beam rate,V b ,nominal laser power,P )and volume fraction of equiaxed grains,f ,after laser remelting (laser beam diameter,D b ϭ0.75mm)Internal No.Sample T 0(°C)V b (mm/s)P (W)f (%)GA186A 2013405GA187B 20108209GA184C10001082080GA1831000134027GA1851000100150032GA1882010015003sections of the traces.(EBSD is a technique for the analysis of the local crystal orientation and therefore the grain-structure of materials [16–18].)Cracked SX HPT blades removed from an aircraft engine were used to show the feasibility of a SX repair of real parts by laser generation.The cracked platform was cut,polished and repaired by E-LMF by eight successive laser traces with a laser beam rate,V b ϭ4mm/s.The powder and substrate materials consisted in this case of PWA 1480,a first generation Ni-base superalloy (Table 1).The feeding powder was produced by atomisation in a protective atmos-phere.3.MICROSTRUCTURE SELECTIONPrediction of solidification microstructures requires the modelling of the nucleation and growth of all possible phases.Nucleation will,in many cases,play a critical role in the phase selection process [19,20].In other cases,growth behaviour controls the selec-tion of the microstructure [21].In a more general approach,however,as is necessary for the columnar to equiaxed transition (CET),both nucleation and growth have to be considered simultaneously [22].During solidification of the melt pool obtained by laser treatment,the solid acts as a heat sink and solidi-fication is mostly directional,at least locally.The heat flux is opposite to the growth direction and the rate of advance of the isotherms constrains the solid–liquid interface to grow at an imposed velocity.If the feed-ing material is similar to the substrate,initial solidifi-cation will show an epitaxial growth when the sub-strate is slightly molten.If nucleation and growth of equiaxed grains in the liquid ahead of the columnar front are avoided,an epitaxial,columnar and SX structure is achieved throughout the deposit.A close control of the CET is therefore a necessary condition for successful processing.The CET occurs when nucleation of sufficiently numerous equiaxed grains takes place in the consti-1054GA¨UMANN et al.:SINGLE-CRYSTAL LASER DEPOSITION OFSUPERALLOYSFig.3.Microstructure selection map for superalloy CMSX-4 under the experimental conditions described in the text,show-ing the expected solidification morphology as a function of temperature gradient,G,and solidification velocity,V.The dot-ted line represents the critical condition for E-LMF given by equation(5),with Kϭ2.7ϫ1024(K3.4/m4.4s).The rectangular insert shows the range of conditions which is typical for the LMF process.The squares represent average G and V values for laser processing conditions A,B and C.⌬T nϭ2.5°C,N0ϭ2ϫ1015/m3,f cϭ0.0066.tutionally undercooled liquid adjacent to the columnar dendritic front.Once nucleated,a certain volume frac-tion of equiaxed grains,f,will form,depending on the temperature gradient in the liquid,G,on the sol-idification velocity of the columnar front,V,on the nuclei density of the alloy,N0,etc.This will eventu-ally lead to the CET.This phenomenon has been modelled in different ways[22–24],the most recent and complete of the analytical models being that of Ga¨umann et al.[25].Results of this model applied to superalloys trough a database for superalloys[26]is shown in Fig.3for a nuclei density,N0ϭ2ϫ1015/m3and a nucleation undercooling,⌬T nϭ2.5°C.This microstructure selection map shows the final solidification microstructure,i.e.columnar or equiaxed,for a range of G and V values.An increase in N0,or a decrease in⌬T n extends the equiaxed regime to higher G and lower V values,respectively. The model’s use for superalloys with10components such as CMSX-4is,however,limited by the avail-ability of the thermodynamic data and the long calcu-lation time required.Therefore another approach based on a modification of Hunt’s model[22]will be presented here.By assuming that all the grains nucleate at the same critical undercooling⌬T n,the radius of the equiaxed grains is given by integrating the growth velocity from the time that nucleation starts until the time that the columnar front reaches the grains.After substitut-ing(for steady state conditions)time by undercooling [(d(⌬T)/d tϭϪVG],a relationship can be derived between the temperature gradient,G,the volume frac-tion of equiaxed grains,f,the nucleation undercoo-ling,⌬T n,the number of nucleation sites,N0,an alloy parameter,n(see below),and the dendrite tip undercooling,⌬T.Gϭ1nϩ1·3ΊϪ4p3ln[1Ϫf]N1/30·⌬T·ͩ1Ϫ⌬T nϩ1n nϩ1ͪ(1)Calculation of the CET requires the determination of the dendrite tip undercooling⌬T,i.e.the difference between the equilibrium liquidus temperature of the alloy and the tip temperature.Under normal dendritic growth conditions,the total tip undercooling is the sum of three contributions:a constitutional,a curva-ture and a thermal undercooling.Since for solidifi-cation of metallic alloys,the tip curvature and the thermal contributions are much smaller than the con-stitutional undercooling[8],only the constitutional contribution will be taken into account in the calcu-lations.Moreover,by neglecting the thermal undercooling,a unique relationship can be used for columnar and equiaxed growth.In a multicomponent model considering an inde-pendent solutefield of each component(q elements) [27,28],the constitutional tip undercooling⌬T c is given by⌬T cϭq jϭ1m j(C0,jϪC∗l,j)(2)where,for each solute element j,m j are the slopes of the liquidus,C0,j the nominal concentrations of the alloys and C∗l,j the concentration at the tip in the liquid.The concentration C∗l,j is calculated by the IMS (Ivanstov–Marginal stability)dendrite growth model [29],by assuming a constant Gibbs–Thomson coef-ficient of1.8ϫ10Ϫ7(m K)and equal diffusion coef-ficients for the alloying elements of3ϫ10Ϫ9(m2/s). This calculation was coupled with a ThermoCalc dat-abase for superalloys developed by Thermotech[26], allowing an evaluation of the distribution coefficients, k j,and the liquidus slopes,m j,for each element as a function of the temperature for the alloy CMSX-4. In order to simplify the calculations,the consti-tutional tip undercooling,⌬T c,for columnar and equi-axed dendritic growth is given,approximately,by⌬Tϭ⌬T cϭ(a·V)1/n(3)where a and n are material dependant constants.In Hunt’s original work n was equal to2(linearised binary system,hemispherical dendrite tips,and low Peclet numbers).Here,a more realistic evaluation of the parameters a and n have been undertaken byfit-ting equation(3)to the dendrite tip undercooling cal-culated with the IMS dendrite growth model.A good correlation of⌬T c with equation(3)can only be obtained for a limited range of solidification velo-cities,and gives,for the window of conditions met1055 GA¨UMANN et al.:SINGLE-CRYSTAL LASER DEPOSITION OF SUPERALLOYSduring laser treatment(insert of Fig.3),nϭ3.4andaϭ1.25ϫ106(K3.4/m s].Substituting equation(3)into equation(1),Gϭ1nϩ1·3ΊϪ4p3ln[1Ϫf]·N1/30·(4)ͩ1Ϫ⌬T nϩ1n(a·V)(nϩ1)/nͪ·(a·V)1/nFor solidification under high temperature gradient G,the nuclei density,N0,plays the important role and the nucleation undercooling,⌬T n,can be safely neg-lected†[22,25].As in laser surface treatment con-ditions,the thermal gradient G is high(105–107K/m),⌬T n can be set to zero and the following relationship is obtainedG nVϭaͭ3ΊϪ4p N03ln[1Ϫf]·1nϩ1ͮn(5)This equation is useful for V of the order of cm/s and G of the order of106K/m.The number of nucleation sites N0of CMSX-4has been evaluated experimentally by laser remelting of SX samples,as described previously.Figure4shows EBSD patterns of samples with(a)high and(b)low G n/V ratios.Thefirst remelted trace(sample A)resol-idified with a mostly columnar dendritic morphology (fϭ0.05)while the second(sample C)showed a large fraction of equiaxed grains(fϭ0.8).ForN0ϭconstant,f depends on G n/V.The measured volume fractions f have been plotted as a function of the calculated G3.4/V ratios in Fig.5.A good corre-lation between equation(5)and the experimental measurements can be obtained when N0ϭ2ϫ1015/m3.Hunt proposed that fully equiaxed growth occurs if the volume fraction of equiaxed grains f>0.49, whereas the structure is assumed to be fully columnar if fϽ0.0066.By setting f to the latter lower critical value,f c,in equation(5),a criterion based on the G n/V ratio can be derived which states that the micro-structure is columnar when the following condition is satisfied everywhere in the melt pool:G nV>K(6)In the present case Kϭ2.7ϫ1024(K3.4/m4.4s)and nϭ3.4.This relationship is crucial for a successful E-LMF process.It is represented by the dotted line in the microstructure selection map of Fig.3.As can†Note that under solidification conditions of investment casting of SX blades the situation is opposite:the tempera-ture gradients are much lower and the principal alloy para-meter controlling the CET is⌬T n[30].be seen,this criterion is more restrictive than the tran-sition calculated with the more complete analytical model.The processing conditions for E-LMF must lie on the right-hand side of this limit.The avoidance of equiaxed growth is a necessary condition for successful SX deposition.Another necessary condition is sufficient remelting of the sub-strate to ensure epitaxy between substrate and deposit. This will be treated in the next section.4.PROCESSING PARAMETERSThe temperature gradient,G,and the solidification velocity,V,under laser processing conditions are the most important parameters which govern the solidifi-cation structure of a given alloy.For instance,the CET transition can be characterised by a critical G n/V ratio.However,in the practice of laser processing one controls the processing parameters P,V b,T0or D b, which show complex relationships with the local sol-idification conditions G and V.The thermal gradient is given by the temperaturefield generated by the laser source and the solidification velocity is related to beam velocity and the melt pool shape.Therefore, the heat transfer from the moving laser source into the material and the resulting melt pool geometry must be considered in more detail.LMF is a rather complex process which is con-trolled by mass transfer(powder)and heat andfluid flow in the melt pool.It will be simplified in order to obtain approximate values for G and V as a func-tion of the processing parameters.As stated before, only heat diffusion will be taken into account and the influence of the mass feeding and of convection will be neglected,leading to the simpler case of laser remelting.The mass feeding and the convection have clearly an influence on the melt pool shape[31,32] and consequently on G and V.Their effects will be discussed in Section6.The thermal gradient was calculated by solving the heat diffusion equation with a modified Rosenthal approach.Rosenthal proposed a solution for the tem-peraturefield in the metal for a moving point heat source[33],assuming a semi-infinite body with con-stant physical properties and no latent-heat release. This model was modified for a gaussian laser inten-sity profile[34,35]and was adapted for the top-hat mode of this laser(see Appendix A).The melt pool shape was assumed to be given by the liquidus isotherm.The position of the solid–liquid interface,as represented by the dendrite tips,deviates from that of the liquidus isotherm by the dendrite tip undercooling(which is a function of velocity).As the thermal gradients are high,the influence of⌬T on the exact position of the solid–liquid interface may be neglected.The velocity of the solid–liquid interface is therefore considered to be equal to the rate of advance of the isotherms V iso.The normal velocity of the liqui-dus isotherm is linked geometrically to the heat source velocity,V b,by the angle between the solidi-1056GA¨UMANN et al .:SINGLE-CRYSTAL LASER DEPOSITION OFSUPERALLOYS Fig.4.EBSD maps of the transverse section of two laser surface remelted samples showing (a)an epitaxialand mainly columnar structure (sample A)and (b)equiaxed grain structure (sample C).The colour scale shows the misorientation angle between the crystallite direction and the crystal coordinate system of a reference point(blackspot).Fig.5.Determination of the nuclei density N 0by correlationbetween the measured (Table 2)and the calculated [equation (5)]volume fractions of misoriented (equiaxed)grains as a function of the average G 3.4/V ratio [for a ϭ1.25ϫ106(K 3.4/m s)].fication front normal and the beam direction,q ,as shown by equation (7).|V iso |ϭ|V b |·cos q(7)V iso increases rapidly from zero at the bottom and at the side of the melt pool to a value close to V b at the rear of the melt pool surface [36].The orientation of the substrate will be taken into account in our cal-culations as the dendrites of cubic crystals grow gen-erally along the Ͻ001>direction which is closest to the heat flow direction.Therefore,the dendrite tip velocity V hkl ,where hkl represents the growth direc-tion,is given by the following relationship [10]:|V hkl ||V b |ϭcos qcos y(8)where y is the angle between normal to the solidifi-cation front and the dendrite trunk axis defined by [hkl ].These equations are solved numerically and enable the computation of the temperature gradient and the solidification velocity of the dendrites for laser remelting conditions.Figure 6(a)and (b)show the evolution of V and G at the solid–liquid interface,as a function of the melt pool depth z ,for processing condition C.These have been calculated in the median plan (plan of symmetry)of the melt pool,where y ϭ0(the physical parameters used for com-putation are reported in Table 3).The laser beam moves along a [100]direction with the [001]direction normal to the surface.The arrows in the figure show the time evolution of solidification:the beginning of1057GA¨UMANN et al .:SINGLE-CRYSTAL LASER DEPOSITION OFSUPERALLOYS Fig.6.Evolution of the local solidification variables,as a func-tion of depth z ,calculated in the plane of symmetry of the melt pool (y ϭ0);(a)velocity of the isotherm,V iso ,and dendritic velocity along the [001]and [100]directions for processing conditions C (if it would produce columnar grains);(b)tem-perature gradient,G ,for conditions C;(c)G 3.4/V calculated for conditions A,B and C.The arrows show the time evolution of the solidification conditions and the squares represent depthaveraged values.solidification occurs at the bottom of the melt pool and the solidification ends at the melt pool surface,i.e.z ϭ0.It may be seen that the dendritic velocity is greater than or equal to the isothermal velocity.The [001]dendritic velocity is zero at the bottom of the laser trace and rapidly increases until it reaches theTable 3.Values of the physical and thermal properties of CMSX-4used in the calculations of processing parameters and processing maps Melting temperature of Ni 1726(K)Specific heat C p690(J/K kg)Liquidus isotherm T l1660(K)Heat conductivity 22(W/m s)Absorption coefficient b 13(%)aThermal diffusivity a 3.66ϫ10Ϫ6(m 2/s)Alloy density r at 20°C8.7ϫ103(kg/m 3)aThe mean absorption coefficient b for CMSX-4melt and CO 2laser radiation was determined experimentally by a calorimetric technique [38].[100]dendritic velocity (in the direction of and equalto V b )where a 90°growth direction transition is observed.The growth orientation with the smallest velocity,i.e.lowest undercooling or highest tempera-ture is selected [10,37].Figure 6(c)shows the evolution of the G 3.4/V ratio with respect to melt depth for processing condition A,B and C.The maximum depth of the melt pool,z max ,is a function of the processing conditions,but the three ratios are highest at the bottom of the laser trace and decrease when z approaches zero (in the particular case of sample A,the ratio is not at its minimum at the top of the trace,due to the particular behaviour of the thermal gradient).In these diagrams only columnar dendritic growth is calculated as only this type of dendrite growth per-mits judging the possibility of a CET (even if the final result lies completely in the equiaxed range as is the case in example C in Fig.6).In order to facilitate the comparison of the influ-ence of various sets of laser processing parameters on the solidification morphology,characteristic valuesV¯z and G ¯z will systematically be calculated as an average over the depth z of the trace along the liqui-dus isotherm,in the median plan of the pool.For G this isG¯z ϭ1z max ͵z maxG ·d z (9)The mean value of the G n /V ratio can be calculatedcorrespondingly:ͩG nVͪzϭ1z max ͵z maxG nV·d z (10)These values are reported in Fig.6as squares,and are characteristic for a given set of processing con-ditions.For instance,it can be shown that the charac-teristic temperature gradient G¯z drops when the laser power P increases.Figure 7shows the evolution of the solidification conditions for processing conditions A,B and C (Table 2)superimposed on the microstructure selec-tion map for CMSX-4(inset of Fig.3).The arrows show the direction of the evolution from the begin-。