ZrN/WN纳米多层膜的结构与性能研究

选择锆和钨的氮化物作为个体层材料,利用超高真空射频磁控溅射系统制备ZrN、WN及一系列的ZrN/WN多层薄膜.通过XRD,SEM和纳米力学测试系统分析了该体系合成中调制周期与ZrN、WN单层厚度比例(tZrN/tWN)对多层膜结构与机械性能的影响.结果表明:大部分多层膜的纳米硬度与弹性模量值都高于两种个体材料硬度的平均值;当调制周期Λ=30nm,tZrN:tWN=2:3时,结晶出现多元化,多层膜体系的硬度、应力以及弹性模量均达到最佳效果.多层膜的机械性能改善明显与其多层结构和多晶结构有直接的联系.     

Ar/N2气体比例对ZrN/WN纳米多层膜的结构和性能的影响

选择Zr和W的氮化物作为个体层材料,利用FJL560CI2型超高真空射频磁控与离子束联合溅射系统制备ZrN,WN及一系列的ZrN/WN多层薄膜.通过X射线衍射仪,俄歇电子能谱和纳米力学测试系统分析了该体系合成中Ar/N2气体比例对多层膜结构与机械性能的影响.结果表明多层膜的纳米硬度值普遍高于两种个体材料混合相的硬度值;当流量比FArFN2=5时W2N的(111)峰加强并出现(200)峰,结晶出现多元化,多层膜体系的硬度、应力、弹性模量以及膜基结合性能均达到最佳效果.     

ZrN/TiAlN纳米多层膜的制备及其结构与性能的研究

利用高真空离子束辅助沉积系统在室温下制备了ZrN,TiAlN和一系列ZrN/TiAlN纳米多层膜,利用X射线衍射仪、纳米力学测试系统和多功能材料表面性能实验仪表征了薄膜的微结构和机械性能,分析了调制周期对薄膜结构与机械性能的影响.结果表明大部分多层膜的纳米硬度与弹性模量值都高于两种个体材料硬度的平均值,当调制周期为6.5 nm时,多层膜硬度达到最高(30.1 GPa),弹性模量、粗糙度、摩擦以及划痕测试均达到最佳效果.     

Zr基氮化物／金属Cu纳米多层膜的强韧化研究

多层结构可以提高材料的强度、弹性模量和韧性。当尺寸减小到纳米量级时,性能将产生飞跃变化。首先探讨了多层结构提高强度、弹性模量和韧性等性能的基本原理,然后阐明了纳米尺度效应及理论,重点以过渡族金属氮化物ZrN纳米多层膜为例,研究了氮化物／金属（ZrN／Cu）纳米多层膜、ZrAIN纳米复合膜以及ZrAIN／Cu纳米多层膜的强韧化性能。结果表明,ZrN／Cu纳米多层膜的断裂韧性约是二元ZrN薄膜的2倍。当纳米多层膜的Cu单层厚度为2013131时,多层膜的K1C值最高。ZrAIN复合膜的断裂韧性与Al含量密切相关,当Al原子分数为23％时,薄膜的KIc值达3．17MPa·m^1/2,其硬度〉40Gpa,Al原子分数为47％的薄膜的K1C值则降低到1．13MPa·m…。,其硬度降低至17．1GPa。与z州／cu纳米多层膜和ZrAlN复合膜相比,以ZrAIN层和cu层为调制结构制备的ZrAlN／Cu纳米多层膜具有最高的硬度和最好的韧性。     

用IBAD方法合成ZrN/W纳米多层膜

本文利用高真空离子束辅助沉积系统（IBAD）在室温下制备具有纳米尺寸的ZrN／W多层膜，通过改变双靶的沉积时间，合成一系列的具有不同调制周期（3nm～10nm）的纳米多层膜。利用AES，XRD和纳米力学测试系统，表面形貌仪表征了薄膜的成分、结构和机械性能，分析了不同调制周期对薄膜结构与机械性能的影响。结果表明：多层膜的机械性能普遍优于两种个体材料的混合相；在调制周期为8．6nm时，显示出强的ZrN（111），W（110）织构和较弱的ZrN（220）峰，与其他条件下制备的样品比较，它具有较高的硬度（～26GPa），较高的弹性模量（-310GPa）和较强的膜基结合力（～80mN）。低角度XRD分析证明了薄膜的多层结构。     

调制结构对TiN/ZrN纳米多层膜的表面形貌、生长行为及力学性能的影响

利用射频反应磁控溅射方法,设计并制备了一系列不同调制周期的TiN/ZrN纳米多层膜.利用原子力显微镜、X射线衍射仪和纳米压痕仪对多层膜的表面形貌、微观结构和力学性能进行了系统表征.研究结果表明调制结构影响着薄膜的择优生长取向、沉积速率和表面形貌;在调制周期为7nm～26nm的范围内,随调制周期的增加,TiN/ZrN多层膜的织构取向有从(100)面向(111)面转变的趋势;TiN和ZrN层的沉积速率随调制周期的变化而变化.在调制周期为15nm左右时,表面粗糙度最小,减小和增加调制周期均导致粗糙度的增加.力学性能分析表明TiN/ZrN多层膜的硬度和弹性模量均高于单一TiN和ZrN的硬度和弹性模量,且随着调制周期的减小有逐渐增加的趋势.此外,根据调制结构和力学性能的分析结果,讨论了TiN/ZrN纳米多层膜的硬化机制.     

ZrN/TiSiN纳米多层膜的微观结构和力学性能研究

采用反应磁控溅射的方法,利用Zr靶与TiSi复合靶成功制备了不同TiSiN层厚度的ZrN/TiSiN纳米多层膜。利用X射线衍射(XRD)、高分辨透射电子显微镜(HRTEM)、扫描电子显微镜(SEM)和纳米压痕仪研究了不同TiSiN层厚度对ZrN/TiSiN纳米多层膜的微观结构和力学性能的影响。结果表明,ZrN/TiSiN纳米多层膜主要由面心立方的ZrN相组成,随着TiSiN层厚度的增加,纳米多层膜的结晶程度先增加后降低,其硬度和弹性模量也先升高后降低。当TiSiN层厚度为0.7nm时,纳米多层膜具有最高的硬度和弹性模量,分别为28.7和301.1GPa,远超过ZrN单层膜。ZrN/TiSiN纳米多层膜的强化效果可由交变应力场和模量差理论进行解释。     

c-AIN的生长对AIN/(Ti,Al)N纳米多层膜力学性能的影响

采用反应磁控溅射制备了具有不同调制周期的AIN/(Ti,Al)N纳米多层膜,研究了亚稳相立方氮化铝(c-AIN)在纳米多层膜中的生长条件及其对薄膜力学性能的影响。结果表明:在小调制周期下AIN以立方结构存在,并与(Ti,Al)N层形成同结构共格外延生长,使纳米多层膜产生较大的晶格畸变。与此相应,AIN/(Ti,Al)N纳米多层膜硬度和弹性模量随调制周期的减小呈单凋上升的趋势,当调制周期小于8～10 nm时其增速明显增大,并在调制周期为1.3 nm时达到最高硬度29.0GPa和最高弹性模量383 GPa.AIN/(Ti,Al)N纳米多层膜的硬度和弹性模量在小调制周期时的升高与亚稳相c-AIN的产生并和(Ti,Al)N形成共格结构有关。     

Ar/N2气体比例对TaN/NbN纳米多层膜机械性能的影响

采用射频磁控溅射系统,以TaN和NbN作为体材料,制备了一系列TaN/NbN纳米多层膜.通过XRD,纳米力学测试系统分析了该体系合成中Ar/N2气体比例对多层膜结构与机械性能的影响.结果表明,纳米多层膜的硬度值普遍高于两种个体材料混合相的值;当FArFN2=10时TaN的(110)峰加强,TaN的晶体结构以六方结构为主,NbN的晶体结构以面心立方结构为主,此时,多层膜体系的硬度、弹性模量以及膜基结合性能均达到最佳效果(最大硬度为30 GPa),摩擦磨损实验表明,Ar/N2比为101的TaN/NbN多层膜较其他Ar/N2比的多层膜耐磨性更好,不易发生破损,适合实际应用.     

离子轰击能量对ZrN/TiAlN纳米多层膜性能的影响

使用超高真空离子束辅助沉积系统(IBAD)制备一系列具有纳米调制周期的ZrN/TiAlN多层膜,研究了离子辅助轰击对薄膜性能的影响.结果表明:离子辅助轰击使大部分ZrN/TiAlN多层膜的纳米硬度和弹性模量值高于两种个体材料硬度的平均值;离子的轰击和薄膜表面原子与轰击离子之间的动量传输提高了薄膜的致密度;当轰击能量为200 eV时,多层膜的硬度最高(30.6 GPa),弹性模量、表面粗糙度和摩擦系数等也明显改善.     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.