FUNDAMENTAL PROBLEMS IN PULSED-BIAS ARC DEPOSITION

Arc deposition, a widely used surface coating technique, has disadvantages such as large droplet size and high deposition temperature. Recent trend in its renovation is the introduction of pulsed bias at the. substrate. The present paper attempts to describe the deposition process of TiN films using this technique with emphasis laid on the understanding of the basic problems such as discharge plasma properties, temperature calculation, and droplet size reduction. We show that this technique improves the film micro structure and quality, lowers deposition temperature, and allows coatings on insulating substrates. After analyzing load current oscillation behaviors, we have determined that the plasma load is of capacitance nature due to plasma sheath and that it is equivalent to a circuit element consisting of parallel capacitance and resistance. At last, we point out the remaining problems and future development of the pulsed-bias arc deposition technique.     

MODELLING AND SIMULATION IN HEAT TREATMENT AND SURFACE ENGINEERING

下面刊发的一篇英文文稿是由国际材料热处理和表面工程联合会 (IFHTSE)秘书长RobertBWood先生亲自撰写的一篇会议述评 ,高度评价了在上海召开的首届国际热加工数学模型和计算机模拟国际会议 ( 2 0 0 0 .0 3.2 8 30 ,上海交大 ) ,对会议卓有成效的组织工作、与会代表相当广泛的覆盖面、会议论文的学术水平以及全部采用英语作为工作语言等方面具有真正国际性会议而备加称赞。     

ELIMINATION OF σ-PHASE IN SUPERALLOYS BY LASERGLAZE

用激光表面熔凝的方法研究激光快冷对改善部件表面状态的作用。结果表明,在激光熔区合金组织发生明显改变,成分均匀,粗大碳化物及共晶组织全部熔化,高温稳定性良好。预先激光处理能抑制σ相析出。已经析出的σ相,激光处理又可使其重熔,这对高温材料的安全使用是很有益的。是一种消除σ相等有害组织的新的技术途径。此外,还分析了快速熔凝的结晶特性及消除σ相的机理。     

INVESTIGATION ON THE INTERFACE PHASE BY TEM IN A NEWLY DEVELOPED NEAR α TITANIUM ALLOY

ＩＮＶＥＳＴＩＧＡＴＩＯＮＯＮＴＨＥＩＮＴＥＲＦＡＣＥＰＨＡＳＥＢＹＴＥＭＩＮＡＮＥＷＬＹＤＥＶＥＬＯＰＥＤＮＥＡＲαＴＩＴＡＮＩＵＭＡＬＬＯＹＭａｏＰｅｎｇｌｉｎｇ；ＸｕＪｉａｌｏｎｇ（ＳｈａｎｇｈａｉＩｒｏｎ＆ＳｔｅｅｌＲｅｓｅａｒｃｈＩｎｓｔｉ...     

BAINITE STRUCTURE IN Cu-Zn-Al ALLOY OBSERVED BY SCANNING TUNNELING MICROSCOPE

ＢＡＩＮＩＴＥＳＴＲＵＣＴＵＲＥＩＮＣｕ－Ｚｎ－ＡｌＡＬＬＯＹＯＢＳＥＲＶＥＤＢＹＳＣＡＮＮＩＮＧＴＵＮＮＥＬＩＮＧＭＩＣＲＯＳＣＯＰＥ￥ＬｉＣｈｕｎｍｉｎｇ；ＦａｎｇＨｏｎｇｓｈｅｎｇ；ＦｅｎｇＱｉｎｇｌｉｎｇ；ＺｈｅｎｇＹａｎｋａｎｇ（Ｄｅｐａｒ...     

EXTENSION OF SOLID SOLUBILITY BY MECHANICAL ALLOYING IN Fe-Cu SYSTEM

Mechanical alloying was employed to produce super—saturated solution of Fe_1-xCu_x ,whichis virtually immiscible under an equilibrium condition at ambient temperature.XRD resultsshow that the solutions formed in the concentration ranges of x≤O.15 and x≥0.40 are of beestructure of x-Fe and fee structure of Cu,respectively.For the region in between(0.15相似文献   

THE SEPARATION CRITERION OF IMPURITIES IN CRUDE METALS BY VACUUM DISTILLATION

ＴＨＥＳＥＰＡＲＡＴＩＯＮＣＲＩＴＥＲＩＯＮＯＦＩＭＰＵＲＩＴＩＥＳＩＮＣＲＵＤＥＭＥＴＡＬＳＢＹＶＡＣＵＵＭＤＩＳＴＩＬＬＡＴＩＯＮ￥Ｌｉｕ，Ｒｉｘｉｎ（ＩｎｓｔｉｔｕｔｅｏｆＣｈｅｍｉｃａｌＭｅｔａｌｌｕｒｇｙ，ＣｈｉｎｅｓｅＡｃａｄｅｍｙｏｆＳ...     

ON DEGRADATION OF DUCTILITY INDUCED BY HYDROGEN IN MEDIUM CARBON STEELS

Optical microscope,SEM and IMMA investigation show that a strong interaction betweenhydrogen and calcium aluminate inclusions containing MgO may occur in medium carbonsteels.This causes the hydrogen accumulating around the inclusions and reducing the ductilityof the steel.     

PRECIPITATION IN A Cu-BASED SMA

ＰＲＥＣＩＰＩＴＡＴＩＯＮＩＮＡＣｕ－ＢＡＳＥＤＳＭＡＣｈａｎｇ；ＦｅｎｇｌｉａｎＷａｎｇ；ＳｈｉｄｏｎｇＷａｎｇ；ＹｕｒｕｉＺｈａｏ；Ｌｉａｎｃｈｅｎｇ（ＡｎａｌｙｔｉｃａｌａｎｄＴｅｓｔｉｎｇＣｅｎｔｅｒ，ＳｏｕｔｈｅａｓｔＵｎｉｖｅｒｓｉｔｙ，...     

STUDIES OF β-PHASE IN Co-Ga BINARY SYSTEM BY POSITRON ANNIHILATION

<正> 在Co-Ga二元系中,β相的理想成分CoGa在室温的单相均匀范围为36.3—59.8at.-％Ga,它属于立方晶系的CsCl型结构,其点阵常数随Ga成分而变化,在接近理想成分的48at.-％Ga处有一最大值。在富Co端,为替代式固溶体。因为Co原子半径比Ga小,所以可以用原子半径大小来解释其实验现象。但在理想成分的富Ga一端,如果也属于替代式固溶体,则随着Ga含量的增加,点阵常数应增加,但实验的结果与此相反,因此文     

GRAIN BOUNDARY EMBRITTLEMENT BY μ AND σ PHASES IN IRON-BASE SUPERALLOYS

本文研究了15Cr-25Ni和15Cr-40Ni型铁基高温合金中μ和σ相引起的晶界脆化。在铁基高温合金中当晶界存在少量的μ和σ相时(甚至其含量在0.01—1％间),就会引起合金脆化,其脆化程度与晶界存在的μ和σ相的密集系数成正比关系。冲击试验时的脆化导致沿晶断裂,μ和σ相所引起的断裂机构是完全不同的。减小晶粒尺寸或控制合金化学成分使晶界上的μ和σ相减少或根本不生成,则可以控制或消除合金的脆化效应。     

IN SITU GRADIENT DOUBLE-LAYER COMPOSITES OF Al-Fe ALLOY BY CENTRIFUGAL CASTING

ＩＮＳＩＴＵＧＲＡＤＩＥＮＴＤＯＵＢＬＥＬＡＹＥＲＣＯＭＰＯＳＩＴＥＳＯＦＡｌＦｅＡＬＬＯＹＢＹＣＥＮＴＲＩＦＵＧＡＬＣＡＳＴＩＮＧ①ＷａｎｇＱｕｄｏｎｇ，ＪｉｎＪｕｎｚｅＲｅｓｅａｒｃｈＣｅｎｔｅｒｏｆＦｏｕｎｄｒｙＥｎｇｉｎｅｒｉｎｇ，Ｄａｌ...     

Ti_3Al PHASE PRECIPITATION DURING VIBRATION FATIGUING FOR A TITANIUM ALLOY

Ｔｉ_３ＡｌＰＨＡＳＥＰＲＥＣＩＰＩＴＡＴＩＯＮＤＵＲＩＮＧＶＩＢＲＡＴＩＯＮＦＡＴＩＧＵＩＮＧＦＯＲＡＴＩＴＡＮＩＵＭＡＬＬＯＹ￥ＴａｏＣｈｕｎｈｕ；ＺｈａｎｇＳｈａｏｑｉｎｇ；ＹａｎＭｉｎｇｇａｏ（ＩｎｓｔｉｔｕｔｅｏｆＡｅｒｏｎａｕｔｉｃａｌＭ?..     

MEASUREMENT OF ANODIC OVERVOLTAGE BY AMODIFIED CURRENT INTERRUPTION METHOD IN CRYOLITE-ALUMINA MELTS

１ＩＮＴＲＯＤＵＣＴＩＯＮＩｎｔｈｅｅｌｅｃｔｒｏｌｙｔｉｃｐｒｏｄｕｃｔｉｏｎｏｆａｌｕｍｉｎｉｕｍ，ｔｈｅｃｅｌｃｏｎｓｉｓｔｓｏｆａｃａｒｂｏｎａｎｏｄｅａｎｄａｎａｌｕｍｉｎｉｕｍｍｅｔａｌｃａｔｈｏｄｅ．Ｔｈｅｄｏｍｉｎａｎｔｐｏｔｅｎｔ...     

PHASE INTERFACE SEGREGATION OF Mg IN A Ni-BASE SUPERALLOY IN100

The segregation of Mg to phase interfaces in a nickel base superalloy IN 100 has been investi-gated using EPT(Electron Microprobe Technique).AES(Auger Electron Spectroscopy)and EDS analyses on thin TEM film.The results show that Mg segregates to the phase inter-faces of MC/γ and γ′/γ.The segregation concentration and layer thickness of Mg onMC/γ phase interface are larger than that on γ′/γ phase interface.Mg is not only a grainboundary segregation element,but also a phase interface segregation one.     

FORMATION OF Fe—N COMPOUNDS BY LASER NITRIDATION IN AN ATMOSPHERIC AMBIENT

The formation of Fe-N compounds by laser nitriding in an atmospheric ambient was reported. By CW-CO2 laser irradiation on pure ferrite iron in the atmospheric ambient, Fe-N compounds (including Fe2N, .Fe3AT and Fe4N) are formed as a result of a laser-enhanced and temperature-enhanced reactions. The samples were analyzed with X-ray diffraction. It is found that the laser power density, scanning speed and nitrogen temperature are the main factors influencing the formation of Fe-N compounds. Nitrogen can be activated by pre-heating at some temperature. Nitrogen activation and sample surface melting by CW-CO2 laser greatly enhance the reaction between the sample surface and nitrogen beam. After annealing at 500℃for 3h, some Fe2N and Fe3N converted into more stable Fe4N.     

STRESSES AND DISPLACEMENTS IN ORTHOTROPIC LONG STRIP LOADED BY SYMMETRIC LOCAL UNIFORM FORCES

ＳＴＲＥＳＳＥＳＡＮＤＤＩＳＰＬＡＣＥＭＥＮＴＳＩＮＯＲＴＨＯＴＲＯＰＩＣＬＯＮＧＳＴＲＩＰＬＯＡＤＥＤＢＹＳＹＭＭＥＴＲＩＣＬＯＣＡＬＵＮＩＦＯＲＭＦＯＲＣＥＳＳＴＲＥＳＳＥＳＡＮＤＤＩＳＰＬＡＣＥＭＥＮＴＳＩＮＯＲＴＨＯＴＲＯＰＩＣＬＯＮＧＳＴＲ...     

MAGNETORESISTANCE EFFECT OBSERVED IN Fe／Mo MULTILAYERS PREPARED BY ELECTRON BEAM EVAPORATION

The Fe/Mo multilayers were prepared by electron beam evaporation, the micro structure and magnetic properties of the multilayers were studied by X-ray diffraction, vibrating-sample magnetometer (VSM) et al. The experimental results revealed that the Fe/Mo multilayers in our experimental conditions behaved magnetoresistance effect with a sharp peak on magnetoresistance (MR) ratio curve, and magnetoresistance is easily saturated at low applied magnetic fields. For [Fe(1.5nm)/Mo(1.0nm)]4,2 multilayers, MR ratio could arrive to 0.1%. The antiferromagnetic interlayer coupling could be observed in some films at room temperature. The strength of the antiferromagnetic interlayer coupling J in the films is low because of the low saturation field Hs. The relationship between magnetic properties and micro structure was also discussed in this paper.     

INFLUENCE OF Al ON DUCTILITY IMPROVEMENT BY B IN Ni_3Al ALLOYS

The “order-disorder” model was adopted to calculate the lattice vacancies related to the com- position change in Ni_3Al alloys.A great deal of vacancies,i.e.,the non-stoichiometric vacan- cies,may exist in the Ni_3Al alloys containing Al over stoichiometry,i.e.25 at.-%.This was confirmed by the positron annihilation technique.Therefore,the influence of Al content on the enhancing behaviour of B towards the ductility of Ni_3Al alloys can be understood by the interaction of non-stoiehiometric vacancies and B atoms.     

CONTROLLING HIGHTEMPERATURE DEFORMATION BY VARYING MICROSTRUCTURE IN A Ti47Al2Cr2Nb ALLOY

１　ＩＮＴＲＯＤＵＣＴＩＯＮγＴｉＡｌａｌｌｏｙｓａｒｅａｔｔｒａｃｔｉｖｅｓｔｒｕｃｔｕｒａｌｍａｔｅｒｉａｌｓｂｅｃａｕｓｅｏｆｔｈｅｉｒｐｏｔｅｎｔｉａｌａｐｐｌｉｃａｔｉｏｎｓｉｎａｅｒｏｓｐａｃｅａｎｄａｕｔｏｍｏｂｉｌｅｉｎｄｕｓｔｒｉｅｓ［１］．ＣｕｒｒｅｎｔｒｅｓｅａｒｃｈｏｎγＴｉＡｌｉｓｐｒｉｍａｒｉｌｙｆｏｃｕｓｅｄｏｎｉｍｐｒｏｖｉｎｇｉｔｓｒｏｏｍｔｅｍｐｅｒａｔｕｒｅｄｕｃｔｉｌｉｔｙ,ｔｏｕｇｈｎｅｓｓａｎｄｈｉｇｈｔｅｍｐｅｒａｔｕｒｅｃｒｅｅｐｒｅ…