氦离子注入对Ti6Al4V合金组织和力学性能的影响

在室温和400～700℃条件下,采用 1×1017ions/cm2注入剂量和200keV加速电压对 Ti6Al4V合金进行了氦离子注入.分别采用纳米硬度仪和X射线衍射方法对Ti6Al4V合金的氦离子注入表面层(≤700nm)进行了纳米硬度、弹性模量测试和物相分析.结果表明:在室温至600℃范围内,氦离子注入温度越高,Ti6Al4V合金注入层的硬度也越高,而其弹性模量则变小.氦离子注入温度为700℃时,Ti6Al4V合金发生了软化,其弹性模量也有所提高.氦离子注入引起的硬化现象与点缺陷和Ti6Al4V合金中β相的析出有关,而软化现象则与β相的粗化和γ-TiH相的形成有关.     

热处理对Al-Cu合金电导率的影响

通过电导率测量、硬度分析和金相组织观察,研究了不同热处理工艺对Al-4.0%Cu(质量分数,下同)合金电导率的影响,分析了析出相、合金硬度和电导率之间的关系。实验结果表明,Al-4.0%Cu合金的电导率主要受基体中Cu固溶度和析出相状态的影响;双级时效处理对电导率和硬度的决定因素主要为二级时效的温度与时间,一级时效后合金的电导率和硬度会随着二级时效发生改变;退火后的Al-4.0%Cu合金于350℃保温24h后,可获得较高的电导率,此时基体中的析出相为细小、弥散的θ相。     

Ar和Xe在Al(Cr)薄层中的扩散和释放

采用2MeV ~4He~+离子的卢瑟福(Rutherford)背散射技术详细地研究了Ar和Xe在Al(Cr)薄层中的扩散和释放行为。Al(Cr)层中的Ar和Xe是由离子注入引入的,注入的能量为30KeV,Ar的注入剂量为4.3×10~16at./cm~2;Xe的注入剂量为5.2×10~15at·/cm~2恒时退火累积分数释放额的测量表明,Ar和Xe在Al(Cr)层中有着十分不同的释放行为,Ar的迁移和释放较快,而Xe没有观察到明显的释放。气体原子尺寸的不同使得它们与晶格缺陷有着十分不同的束缚能。     

铝合金等离子体淹没离子注入氮层组织及其耐磨性

用等离子体淹没离子注入技术向硬铝ＬＹ１２和锻铝ＬＤ１０注入氮离子，剂量范围为２×１０＾１７～１×１０＾１８Ｎ＾＋－ｃｍ＾－２，并用Ａｕｇｅｒｙ谱（ＡＥＳ）及透射电镜（ＴＥＭ）分析注入层的浓度分析及组织结构，利用机械性能显微探针测量注入层的纳米硬度，进行了磨损试验，氮离子注入到铝合金中能形成细小弥散的ＡｌＮ析出相，显著提高合金表层纳米硬度，耐磨随着注入剂量的增加而提高。     

锆、钒离子注入铝形成金属间化合物

利用金属蒸气真空弧离子源,将大束流Zr和V离子注入到Al中,在离子注入过程中直接形成了金属间化合物Al3Zr,Al10V和Al3V.当Zr离子束流密度为64μA/cm2,剂量为5×1017ions/cm2时,在Al表面形成了稳定相DO23-Al3Zr和亚稳相L12-Al3Zr.当V离子束流密度为51μA/cm2,剂量为3×1017ions/cm2时,在Al表面形成了Al10V和Al3V.Zr和V离子注入到Al中使Al表面的硬度和弹性模量明显提高.     

Ti膜的离子注入表面强化效应研究

本文研究了Ar~++N~+注入铍表面Ti膜后,表面层的强化效应。实验先以Ar~+注入(剂量为4.5×10~(16)/cm~2),再注入N~+(剂量分别为1.6×10~(17)/cm~2、3.3×10~(17)/cm~2、5.5×10~(17)/cm~2),研究表面硬度及磨损速率随N~+注入剂量的变化关系,结果表明,N~+注入对表面硬度及耐磨性能有很大改进,并有一最佳剂量。X射线衍射分析得到,N离子注入后表面生成了TiN硬质相,并用RBS观察了膜与基体间的界面情况。     

Fe_2Al基金属间化合物合金的焊接研究进展

Fe_3Al基合金成本低廉、密度较低、抗氧化及抗硫蚀性优异,是最接近应用的结构材料之一。“九五”期间的研究,通过合金化及B2热机械处理,室温塑性得到明显改善,达10％～15％以上。 本工作在解决Fe_3Al基金属间化合物合金大体积材料的熔炼、锻造、热轧工艺问题,获得180～200mm宽薄板的基础上,研究了Fe-28Al-5Cr与Fe-28Al-5Cr-0.5Nb-0.1C合金的高温变形行为,发现在850℃左右,应变速率为8.33×10~(-4)s~(-1)时,呈现出大晶粒的超塑性变形行为,延伸率分别达到145％和254％。这意味着不需要获得细晶的特别工艺处理就可以直接进行超塑     

强束流Ta离子注入铝的研究

利用从金属蒸汽真空弧离子源引出的强束流Ta离子 ,进行了Ta离子注入铝的研究。研究结果表明 ,在离子注入剂量为 5× 10 17cm- 2 ,平均束流密度为 4 0 μA·cm- 2 ,加速电压为 4 2kV下 ,Ta离子注入能在铝表面形成相应的合金层。借助卢瑟福背散射 (RBS)和X射线衍射 (XRD)分析 ,我们发现表面合金层中形成了Al3Ta相 ,Ta在铝中能产生 10 %以上的原子百分浓度 ,其深度高达 2 0 0nm。     

高弹性软磁合金CD-1的特性及其应用

本合金为中镍型Fe-Ni合金,并含有W、Ti、Al等组元。合金兼备高弹性、高硬度、高饱和磁感和高导磁性能。合金采用沉淀析出方法使之强化。经热处理后合金性能(1.5mm厚冷轧带):μ_0=5.15×10~(-3)H/m,μ_m=7.15×10~(-2)H/m,B_s=1.31,H_c=4.77A/m,σ_b=800MPa, σ_s=390MPa,Hv=230。该合金性能与软磁合金1J50相比,软磁性能两者相近,而弹性和硬度提高一倍。合金用作磁回路弹性结构件或受力导磁体,获得了满意的使用效果。     

均匀化退火等温冷却对Mg-10Al-1Zn镁合金组织性能的影响

对Mg-10Al-1Zn镁合金进行均匀化退火等温冷却处理,探讨等温温度和时间对β-Mg17Al12相析出形貌和合金力学性能的影响。研究结果表明:在420℃保温24h再经200~300℃保温1~6h后,β-Mg17Al12相均以层片状形态均匀析出。β-Mg17Al12相析出量随时间延长而增加,平均层片间距随等温温度升高而增大。合金在420℃保温24h再经250℃保温2h后,布氏硬度达到最高值80.1HB。     

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.     

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...     

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.     

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.     

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 ...