Fe_(75)Nb_8B_(15)Zr_2非晶合金的晶化过程研究

采用单辊快淬法制备Fe75Nb8B15Zr2非晶合金,对该非晶合金进行不同温度的等温退火,研究其晶化过程及结构变化.利用示差热分析仪(DTA)确定样品的退火温度,利用X射线衍射(XRD)测试其相结构.结果表明:Fe75Nb8B15Zr2合金在快淬速率为38m/s时呈完全非晶状态,随着退火温度的升高,α-Fe相逐渐析出,并伴随有硼化物(Fe3B和Fe2B)析出.Fe75Nb8B15Zr2非晶合金的晶化过程:非晶→非晶+α-Fe→α-Fe+Fe3B→α-Fe+Fe3B+Fe2B.     

Cr、V元素替代Nb元素对Fe40Co40Zr8Nb2B10非晶合金热性能及结构的影响

采用单辊快淬法制备Fe40Co40Zr8Nb2B10、Fe40Co40Zr8Cr2B10和Fe40Co40Zr8V2B10非晶合金薄带,并对三种合金在不同温度下进行热处理.利用X射线衍射仪(XRD)和差热分析仪(DTA)等测试手段对样品的结构及热性能进行研究.结果表明,Fe40Co40Zr8Nb2B10、Fe40Co40Zr8Cr2B10和Fe40Co40Zr8V2B10合金的晶化激活能分别为302.6、306.6和299.3 kJ/mol,Cr元素和V元素替代Nb元素对合金的热稳定性影响不大,但扩大了合金的晶化温区.三种合金晶化过程相似:非晶→非晶+α-FeCo→α-FeCo+ZrCo3B2+Fe(Co)3Zr.     

Cu,Zr对Al-Ni-Zr-Cu-Y非晶合金的形成和热稳定性的影响

采用单辊旋淬技术,在真空条件下制备了快速凝固Al85Ni10Zr3Y2四元合金条带和Al80Ni10Zr8-xCuxY2(x=1,2,3,5)五元合金条带.利用X射线衍射及差热分析对条带进行了研究.结果表明,w(Cu)和w(Zr)对该合金系的非晶形成能力及热稳定性有显著影响,并且非晶合金的形成对这两种元素的质量分数很敏感.当w(Cu)和w(Zr)其中一种达到一较大值时,可以形成非晶合金或是以非晶相为主的合金,否则将只能得到晶体相.另外,Al80Ni10Zr7Cu1Y2,Al80Ni10Zr3Cu5Y2合金系具有较强的非晶形成能力,可形成完全非晶或以非晶为主体和部分晶体的复相材料.     

Ni-Fe-Zr-Si-B非晶合金的形成和热稳定性研究

通过旋铸急冷工艺在真空中制备出了(Ni0.75Fe0.25)78-xZrxSi10B12(x=1、3、5、8、10)合金带材,获得了镍基非晶合金.采用XRD、DTA等测试手段分析了该工艺制备的合金非晶条带,研究了Zr对该合金体系的非晶形成能力和热稳定性的影响.X射线衍射分析表明,该合金体系皆为完全非晶.Diamond TG/DAT差热分析仪对非晶薄带的热稳定性及其相关参数Tg、Tx、Tm等的测量分析表明,该合金系中(Ni0.75Fe0.25)70Zr8Si10B12的过冷液相区温度范围ΔTx达58.62 K,约化玻璃转变温度trg约为0.666,表明该合金具有较高的非晶形成能力和热稳定性.当Zr原子分数较小(x≤8)时,Zr的添加提高Tg、Tx,并扩大过冷液相区ΔTx,使合金的非晶形成能力和热稳定性增加;Zr原子分数较大(x>8)时,Zr的添加诱导富Zr-Ni和Zr-Fe的原子团的形成,这些原子团会成为均质形核的核心,降低合金的非晶形成能力和热稳定性.     

Ni-Fe-(Zr)-Si-B非晶合金的等温晶化与结构转变

采用旋铸急冷工艺在大气环境中制备出了(Ni0.75Fe0.25)78-xZrxSi10B12(x=0、8)非晶合金带材.X射线衍射分析表明样品为完全非晶.采用Diamond TG/DTA差热分析仪测量非晶薄带的热稳定性及其相关参数Tg、Tx、Tm等.根据DTA结果分析,(Ni0.75Fe0.25)78Si10B12非晶合金退火温度为695、715、7457、65 K.在715 K和745 K退火时,非晶基体上析出单一的-γ(Fe,Ni)固溶体,平均晶粒尺寸分别约为10.3 nm和18.5 nm,在765 K退火后的结晶相为-γ(Fe,Ni)固溶体以及Fe2Si,Ni2Si和Fe3B.(Ni0.75Fe0.25)70Zr8Si10B12非晶合金退火温度为810、825、845、855、865、920 K,退火后不能在非晶基体上析出单一的晶化相,晶化析出相为-γ(Fe,Ni)固溶体以及Ni21Zr2B6,Fe5Si3,Ni3Zr和一些未知相.     

FeCoZrB合金的非晶形成能力及磁性能研究

采用单辊快淬法制备Fe81-xCoxZr9B10(x=0,2,4,6)系非晶合金,对该系非晶合金的非晶形成能力及磁性能进行研究.利用X射线衍射(XRD)和振动样品磁强计(VSM)测试合金的结构及磁性能.研究结果表明:Fe81-xCoxZr9B10(x=0,2,4,6)合金在快淬速率为30 m/s时完全形成非晶.随Co含量的增加比饱和磁化强度(Ms)先增加后减少.     

Fe74B20Ti6和Fe70B20Y4Ti6非晶合金的热性能及非晶形成能力

采用单辊快淬法制备出Fe74B20Ti6和Fe70B20Y4Ti6合金条带,通过X射线衍射仪(XRD)和差热分析仪(DTA)来研究Fe74B20Ti6和Fe70B20Y4Ti6合金的微观结构和热性能.实验结果表明,快淬速率为30 m/s时,Fe70B20Y4Ti6合金已完全形成非晶,而Fe74B20Ti6合金大部分形成非晶,有少量晶化相;其中Fe70B20Y4Ti6合金的过冷液相区宽度ΔTx高达66 K,说明Y元素的添加可以使合金具有较大的热稳定性,较强的玻璃形成能力.     

快速凝固Al85Ni8Zr3Cu2Y2非晶材料的形成及热稳定性分析

采用旋铸急冷工艺分别在大气和真空环境中获得了Al85Ni10Zr5和Al85Ni8Zr3Cu2Y2韧性非晶合金带材,利用X射线衍射和示差扫描量热仪(DSC)对条带的显微结构及热稳定性进行了分析.结果表明,无论在真空还是在大气条件下,Y,Cu元素的添加都提高了Al85Ni10Zr5合金的非晶形成能力及热稳定性.研究发现,合金成分及冷却速率对非晶的形成起了重要作用,而甩带环境对Al Ni Zr合金系的非晶形成影响不大.     

Al_(65)Fe_(10)Zr_(20)Gd_5非晶态合金的制备与晶化

研究Al65Fe10Zr20Gd5混合粉末的机械合金化引起的非晶态化过程,采用X射线衍射仪(XRD)和扫描电镜(SEM)分析混合粉末的结构演变和形貌,用差热分析仪(DTA)分析非晶态合金的热稳定性。结果表明,粉末在机械合金化过程中先细化,由初始粉末直接扩散固溶导致晶格崩溃形成非晶,球磨60h后Al65Fe10Zr20Gd5完全非晶化。DTA曲线显示非晶合金晶化呈现单一的放热峰。合金在923K等温退火1h后,完全晶化,析出复杂的中间相,表现出多晶型晶化的特点,晶化产物为Fe5Gd、Fe2Zr、Al2Gd3和α-(Al)固溶相。Al65Fe10Zr20Gd5非晶晶化激活能为259.64 kJ.mol-1,该非晶合金具有较高的热稳定性和较强的抗晶化能力。     

热处理对Fe_(40)Co_(40)Zr_7V_2B_9Ta_2合金微观结构及磁性能的影响

采用单辊快淬法制备Fe40Co40Zr7V2B9Ta2非晶合金薄带,并对该合金在不同温度下进行热处理.利用差热分析(DTA)、X射线衍射(XRD)、扫描电镜(SEM)和振动样品磁强计(VSM)测量合金的热性能、微观结构及磁性能.结果表明:Fe40Co40Zr7V2B9Ta2合金的初始晶化产物为α-FeCo相,高温时析出ZrCo3B2,Co23Zr6和ZrB2相;薄带横断面的形貌在快淬态和300℃退火后,合金的自由面呈网状结构,贴辊面呈枝状结构;高于550℃退火,横断面呈颗粒状;550℃退火后合金的矫顽力(Hc)最小,高于550℃退火,Hc随退火温度的升高而增大.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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