形变原位铜基复合材料的研究进展

综述了形变原位铜基复合材料的制备方法、组织演变及综合性能特点,介绍了该类材料的强化和导电机理.分析指出:形变原位铜基复合材料兼顾了高强度和高导电性,已成为高强高导铜基导电材料研发领域的热点之一,降低生产成本、研究产业化制备工艺、深入完善基础理论是该类材料的发展趋势.最后探讨了该类材料的应用前景.     

弥散强化铜基复合材料的研究现状与展望

弥散强化铜(DSC)合金因为有一系列优良的性能而逐渐成为很多领域中不可替代的结构功能材料,常用的增强相一般有Al2O3,WC和TiB2,最近,又有一种新的Ti3SiC2陶瓷被用来作为增强相.本文对几种复合材料分别做了介绍,分析了研制弥散强化铜基复合材料中的一些问题,还对该材料的应用进行了展望.     

铜基复合材料的研究新进展

主要从增强体材料、增强机理、制备方法等方面简述了铜基复合材料的研究进展情况,总结了铜基复合材料的增强体材料的选用原则、种类和特点,并根据增强体材料的形态重点阐述了4种增强机理,介绍了7种制备铜基复合材料方法的工艺机理、特点,最后指出了铜基复合材料的应用领域,并展望了该类材料的发展方向.     

高强度高导电性形变铜基原位复合材料的研究进展

形变铜基原位复合材料是高强度高导电性铜合金的研究热点和发展方向之一,其突出的特点是具有超高的强度和良好的电导率。综述了铜基原位复合材料的研究现状,介绍了该类材料的制备工艺、组织演变、强化导电机理和性能特点,重点对其强化机理作了论述,并对该类材料的发展方向作了展望。     

Al2O3弥散强化铜基复合材料的研究现状与进展

综述了Al2O3弥散强化铜基复合材料的各种制备工艺及研究进展,对内氧化法制备Al2O3弥散强化铜基复合材料进行了详细的阐述。着重分析了Al2O3弥散强化铜基复合材料发展过程中遇到的问题,并对其今后的研制方向作了进一步的展望。     

非连续增强铜基复合材料的研究现状

非连续增强铜基复合材料具有很高的导电、导热性能,以及优异的摩擦磨损特性和较高的高温力学性能,是导电、导热、耐磨、减摩等领域的理想材料。本文综述了非连续增强铜基复合材料的研究现状,介绍了该类材料的设计原理以及力学、摩擦磨损、导电导热等性能,回顾了材料的制备工艺,指出了各种工艺的优缺点,最后阐述了非连续增强铜基复合材料的发展方向。     

铜粉对铜基摩擦材料性能的影响

分别以电解铜粉、氧化铝弥散强化铜粉和铁钴铜预合金化铜粉为基体,用粉末冶金工艺制备铜基摩擦材料,研究了铜粉对材料摩擦磨损性能的影响。结果表明,氧化物弥散相和合金元素的存在,影响摩擦膜的成分、厚度和硬度,进而影响摩擦系数。在铜基体中弥散分布的氧化铝陶瓷粒子起稳定摩擦过程、增大摩擦系数的作用,使材料表现岀良好的摩擦系数稳定性;但是,脱落的硬质磨粒使材料的磨损量较大。铁钴复合强化的材料摩擦后没有明显的机械复合形变层,而形成了稳定的氧化膜,摩擦过程始终发生在对偶件与表面氧化膜之间,因此材料的磨耗量低而稳定。     

铍青铜和不含铍的铜基弥散强化弹性合金

一、前言在种类繁多的仪表弹性合金中铜基合金占有重要位置。铍青铜和其它铜基弹性合金传统地被用来制造诸如膜片,弹簧管,波纹管,各类弹簧、簧片等弹性敏感元件。随着信息时代的到来,电子计算机和大规模集成电路迅猛发展,铜基弹性合金作为金属电子材料广泛用于制造各种导电接点载体弹簧,接插元件,引线框架等重要元器件和零部件。本文叙述了铍青铜强化过程的新发展和不含铍的铜基弥散强化弹性合金的特性及其应用前景。     

高强度导电铜基材料的研究现状与发展前景

简述了高强度导电铜基材料的设计思路,分析了时效强化、颗粒强化以及形变复合等3类铜基材料的制备方法和特点,综述了高强度导电铜基材料的研究现状,并展望了其进一步发展的趋势.     

弥散强化铂基材料的研究现状

弥散强化铂基材料是一种先进的结构型与高温型贵金属复合材料,并且是玻璃纤维漏板材料发展的主要方向.综述了弥散强化铂基材料的制备方法及其优缺点,总结了目前弥散强化铂基材料中存在的固溶强化、晶界强化及弥散强化的强化机理及其研究进展,介绍了弥散强化铂基材料的组织结构特点及其蠕变特征、常温高温下的主要性能、应用以及新的发展动向,为弥散强化铂基材料的选择、研究以及工业化应用提供了参考依据.     

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.     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

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.……     

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.     

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.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.