ALCHEMI法测定有序合金的马氏体和贝氏体相的原子组态

虽然Ｃｕ－Ｚｎ－Ａｌ和Ｃｕ－Ａｕ－Ｚｎ合金中的母相已知为ＤＯ３或Ｌ２１结构，但通过通道增强微分析原子定位法（ＡＬＣＨＥＭＩ），可以检测Ｃｕ－Ｚｎ－Ａｌ合金的母相，马氏体相和Ｃｕ－Ａｕ－Ｚｎ合金的母相、马氏体、贝氏体相中的原子配置，结果表明，马氏体相中原子配置与母相是完全一样的，但Ｃｕ－Ｚｎ－Ａｌ合金听时效马氏体的Ｃｕ－Ａｕ－Ｚｎ合金中贝氏体与母相不同。本文叙述ＡＬＣＨＥＭＩ测定的结果。     

BCu50ZnMnNiSi多元铜基钎料的研究

提出了一种含Ｎｉ、Ｓｉ的适合钎焊合金白口铸铁的Ｃｕ基ＣｕＺｎＭｎ多元钎料,并对ＢＣｕ５０ＺｎＭｎＮｉＳｉ钎料的熔化特性、钎焊工艺性能、钎料组织以及力学性能进行了研究。研究结果表明,与普通ＣｕＺｎ合金钎料比较,ＢＣｕ５０ＺｎＭｎＮｉＳｉ钎料钎焊冶金特性优异,界面冶金结合致密,尽管钎料中含有多元合金元素,钎焊后钎缝仍有较好的塑必     

β‘Cu—Zn合金中温区等温转变的研究

利用光学显微镜及透射电镜考察了β＇Ｃｕ－Ｚｎ合金中温区等温转变，发现其转变产物平衡相α１在ＴＴＴ图中具有各自独立的Ｃ曲线，在两Ｃ曲线交叉点温度以下的转变初期，可得到单相的亚稳贝氏体α１，而延长等温时间，α１将部分甚至完全退化为α，初期形成的α１内部具有完整的层错亚结构，其体转变激活能仅约为Ｚｎ扩散激活能的１／２。     

国外文摘

国外文摘９６０７００１Ａｌ－Ｚｎ合金层的研究—ＳｉｎｇｈＩ．ＩＥＥＥＴｒａｎｓＣｏｍ０６１７３０８６．（１９９４．６．２１）ｐｏｎ，１９９４，１７（４）：ｌ（英文）在实验室中成功地用热浸镀方法在低碳钢上制备锌和５５％ＡＩ－－Ｚｎ合金层，从空载电位、失...     

CuZn钎料钎焊白口铸铁润湿性及力学性能

研究了ＣｕＺｎ 系钎料钎焊白口铸铁润湿性及力学性能。结果表明, 含Ｚｎ３８％ ＣｕＺｎ 钎料润湿性和剪切强度最高。ＣｕＺｎ 系钎料在白口铸铁表面的润湿性和钎缝剪切强度低于在 ３５＃ 钢表面的润湿性和钎缝剪切强度。白口铸铁向钎料过度溶解所造成的溶蚀, 是钎料润湿性差和接头强度低的主要原因。     

Zn—5Al合金铸态共晶结构的研究

利用光学显微镜、扫描电镜、透射电镜研究了Ｚｎ－５Ａｌ合金的铸态共晶结构。结果表明，Ｚｎ－５Ａｌ合金的铸态组织为典型的片层状共晶共析结构，其特征可表示为β（α│β│α）β，其中β为Ｚｎ基固溶体，α为Ａｌ基固溶体；括号外的β表示共晶结构中的较宽片层，直接来源于共晶反应，括号内的部分表示共晶结构中的较窄片层，是由α和β两相组成的共析产物，是由α和β两相组成的共析产物，其中α相包裹着β相。     

CuZn钎料钎焊白口铸铁润湿性及动力性能

研究了ＣｕＺｎ系钎料钎焊白口铸铁润湿性及力学性能。结果表明,含Ｚｎ３８％ＣｕＺｎ钎料润湿性和剪切强度最高。ＣｕＺｎ系钎料在白口铸铁表面的润湿性和钎缝剪切强度低于在３５＃钢表面的润湿性和钎缝剪切强度。白口铸铁向钎料过度溶解所造成的溶蚀,是钎料润湿性差和接头强度低的主要原因。     

SiCw＋B4Cp／MB15镁基复合材料力学性能与微观结构

对真空反压浸渍方法制备的挤压态ＳｉＣＷ＋Ｂ４ＣＰ／ＭＢ１５镁基复合材料及基体合金进行了一系列的力学性能测试，并用ＳＥＭ观察增强剂分布与断口形貌，用ＴＥＭ和ＥＤＳ方法对复合材料的界面结构进行分析。研究结果表明，上述复合材料同基体相比有更高的强度、弹性模量和比强度、比弹性模量。深浸蚀ＳＥＭ相分析表明均匀排布的晶须、颗粒起到很好的增强效果。复合材料的断口有晶须露头与韧窝存在，该复合材料具有一定的韧性；并在ＳｉＣ／ＭＢ１５界面上发现Ｚｎ析出相。     

时效过程Cu－Zn－Al合金阻尼特性的研究

本文研究了热处理工艺对Ｃｕ－１４．１４Ｚｎ７．９７Ａｌ（ｗｔ％）合金自然时效阻尼特性的影响。合金的阻尼性能依赖于分级淬火参数Ｔ＿ｂ及ｔ＿ｂ且随时效时间的延长存在“峰效应”。Ｔ＿ｂ＝２００℃的分级淬火减少了时效过程中阻尼的损失，使合金处于稳定的高阻尼状态。Ｘ－ｒａｙ衍射分析表明，合金在自然时效时其结构有序度发生改变且有α相析出。合金阻尼特性的波动与空位等点缺陷和界面的相互作用及α相的析出有关。     

Zn－Al共析合金室温超塑性变形机理

本文用电镜等对室温下超塑性变形中的Ｚｎ－２２％Ａｌ共析合金的组织变化进行了观察，发现在该合金中α相（富Ａｌ相）＋β相（富Ｚｎ相）两相组织中，在三叉晶界存在亚微观破坏区和显微孔洞，在α、β晶界的某些区域存在条纹带，某些晶粒内部存在大量位错及其缠结。据此得出超塑性变形的主要机制是晶界滑动、孔洞和位错运动松弛晶界引起应力集中，协调了晶界滑动的连续进行。条纹带是晶界迁移的结果。     

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.……     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

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.……     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

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 ...