稀土化学热处理进展

综述了哈尔滨工业大学稀土化学热处理研究和应用成果。包括稀土渗碳及碳氮共渗、稀土渗氮及氮碳共渗、等离子体稀土渗氮、稀土渗硼及硼铝共渗、稀土多元共渗、稀土渗金属工艺技术，稀土的催化和微合金化机制，渗层组织和性能的改善，稀土化学热处理在生产中的应用及其过程的数学模型与计算机仿真等。     

Surface nanocrystallisation engineering: scientific and industrial potential

Abstract

By means of surface mechanical attrition treatment (SMAT), a nanostructured surface layer with a graded grain size distribution ranging from nano-to micrometres can be synthesised on various metallic materials. In this paper, the grain refinement mechanism, mechanical and diffusion properties, and chemical reactivity of the nanostructured surface layer, are reviewed. In addition, effects of the nanostructured surface layer on the mechanical performance and surface thermochemical treatment processes of engineering materials are described. Previous investigations have indicated that the nanostructured surface layer synthesised by means of SMAT on metallic materials provides many unique opportunities in both basic scientific research and technological applications.     

Electron meets nitrogen: combination of electron beam hardening and nitriding

Abstract

Combined heat treatments, also known as duplex or hybrid technologies, offer new structure/property relationships in layered matrix compounds. The treatment sequence is critical. There are within reach both properties and property gradients that are impossible to achieve using the respective single treatment processes alone nor by simple addition of the effects of the single processes. Good technical progress is given by the combination of thermochemical treatment with high energy beam surface hardening, in particular electron beam hardening. After a historical survey (milestones) of the combination of thermochemical with thermal (surface) heat treatment technologies, the paper deals with the principles of the combining electron beam hardening after nitriding and vice versa , electron beam hardening before nitriding and the effects on microstructure and properties. Typical examples of industrial application are discussed. In this field of heat treatment, further development is focused on combinations of high energy beam hardening (electron or laser beam) with hard coating.     

Progress in theory and practice of thermochemical treatment of steels

Abstract

Recent developments in the thermochemical treatment of steels at MADI, Moscow are presented. These technologies combine nitriding with other methods of surface modification, e.g. thermal diffusion and laser alloying, plasma treatment, galvanic and slurry metallisation, and oxidation. By regulating the parameters of each process, it is possible to control the structure of the surface at the micro- and nanoscales, to form coatings and/or surface layers on various carbon and alloyed steels with tailored properties (hardness, wear and corrosion resistance, etc.) for machine parts used in various working conditions.     

几种模具表面强化新技术的简介

本文从电火化、热喷涂、金属表面喷丸，等离子化学热处理，离子注入，TD处理、气相沉积、激光表面处理等几方面介绍了提高模具使用寿命的表面强化新技术。     

提高模具使用寿命的表面强化新技术

本文从热喷涂、等离子化学热处理、气相沉积、TD处理、离子注入处理和激光表面处理等几方面详细介绍了提高模具使用寿命的表面强化新技术。指出正确运用表面强化技术是提高模具使用寿命的一个行之有效的重要途径 ,具有事半功倍的效果。     

Die Anwendungen der elektrochemischen Oberflächenbehandlung von Metallen bei der Herstellung von Apparaten für die chemische Industrie

Applications of the electrochemical surface treatment of metals in the construction of apparatus for the chemical industry In view of the constantly higher requirements concerning the surface quality of chemical apparatus the electrolytical polishing is gaining in importance. By contrast to the mechanical polishing processes the metal structure is preserved (no formation of a beilby layer) and the resulting surface is so smooth that electropolished surfaces are close to an ideally plane surface. Electropolishing can be used also in connection with mechanical polishing in order to remove the Beilby layer formed in the latter. Main applications are the construction of apparatus for unclear technologies and the production of pure reference surfaces for materials and corrosion testing, in particular because it is possible uniformly to polish parts of complex shapes.     

General features of the formation of the carburized layer in thermocyclic saturation

The use of thermocycling in the technology of chemical heat treatment (CHT) of steel parts makes it possible to intensify the processes of diffusion saturation and improve all the properties of parts subjected to surface strengthening. The present paper is devoted to the results of a study of the effect of thermocycling regimes on the formation of the structure and the properties of the diffusion layer of steels subjected to carburizing. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 2, pp. 2–6, February, 1998.     

电子束淬火与渗氮的复合热处理技术

复合热处理,也称作双重或混合技术,提供了具有新的组织／性能关系的基体化合物层,而处理工序是关键。这种技术能达到单项处理工艺或单项工艺的简单叠加所不能达到的性能和性能梯度化学热处理与高能柬表面淬火特别是电子束淬火相结合,使这项技术取得了显著进展。本文在评述热化学与热（表面）处理技术相结合的历程（重大事件）后,介绍了渗氮后进行电子束淬火和电子柬淬火后进行渗氮的原理及其对微观组织与性能的影响,并讨论了典型的工业应用实例、该领域的进一步发展主要是高能束（电子束或激光束）淬火与硬质涂层技术相结合．     

钛合金化学热处理研究进展

钛合金由于存在致密钝化膜、极高的氧亲和力和较低的原子扩散系数,表面强化很难实现。但钛的碳氮化物及固溶相具备优异的性能,通过渗氮、渗碳、渗硼、渗金属4种化学热处理技术可大幅度改变合金表层组织结构,提高表面硬度和强度。对钛合金化学热处理常用技术特征、渗层微观组织结构、强化机制及力学行为进行了归纳总结,并对未来化学热处理发展前景做了展望。     

Development of databases and generation of stability diagrams pertaining to the modelling of processes during hot corrosion of heat exchanger components

The purpose of the project “Optimisation of In‐Service Performance of Boiler Steels by Modelling High Temperature Corrosion” (G5RD‐CT‐2001‐00593, acronym OptiCorr) was to establish a set of focused procedures, both in terms of applications of thermochemical standard software and in terms of dedicated new developments, which enable a user to investigate the behaviour of boiler components based on the application of rigorous thermodynamics. Thermodynamic databases which cover the materials involved had to be compiled and assessed in order to be able to apply the appropriate software. Particular new results coming from the databases work will be highlighted. The results of phase equilibrium calculations are shown in appropriate diagrams and compared with published experimental data. The thermochemical standard software FactSage permits the investigation of stoichiometric reactions, complex equilibria and phase diagrams. These calculational capabilities have been applied for the purposes of investigation of (1) the composition of complex combustion gases, (2) metal‐gas interactions and (3) metal‐gas‐molten salt interactions, since these have been established to be the key points for the understanding of the corrosion of heat exchanger components. Selected results from these calculations will be demonstrated and discussed. Application specific software has been developed using the approach of local chemical equilibrium calculated by the programmer's library ChemApp and the add‐in ChemSheet for Microsoft EXCEL™. Two key processes have been treated: The internal corrosion of the metallic material by diffusion of gases and metals and local phase formation as well as the corrosion of heat exchanger material under a molten salt layer which is in contact with an outer gas phase. The general principles of the code development will be outlined while the details of the programs are given in separate presentations in this volume.     

An investigation into the effect of Triode Plasma Oxidation (TPO) on the tribological properties of Ti6Al4V

Improving the tribological properties of titanium alloys has been the subject of extensive research for many years. A number of thermochemical processes have been developed for that purpose. In this study, surface hardening of Ti6Al4V is achieved by Triode Plasma Oxidation (TPO) which differs from conventional diode plasma treatments through the use of a third electrode; a negatively biased tungsten filament to enhance the ionisation levels in the plasma. The resultant surface generally consists of a top oxide layer with an oxygen diffusion zone lying immediately underneath it. The effects of process parameters such as substrate temperature, current density and oxygen partial pressure have been investigated. Surface hardness measurements at various indentation loads were carried out to assess the changes in hardness with depth across the diffusion layer. The hardness profiles obtained confirmed the gradual decrease in hardness with treatment depth and provided an indication of the thickness of the hardened layer produced. Ball-on-plate reciprocating sliding wear data and glancing angle XRD analyses of the oxidised samples are also presented. The results indicate that a harder and deeper case is achieved at both high substrate temperature and high oxygen partial pressure. Furthermore, XRD data show that the substrate temperature strongly affects the structure of the oxide layer produced. All TPO-treated samples exhibit significantly better wear performance compared to the untreated material.     

金属材料表面纳米化研究与进展

大多数金属材料的失效都是从其表面开始的,进而影响整个材料的整体性能。研究表明,在金属材料表面制备纳米晶,实现表面纳米化,可以提升材料的表面性能,延长其使用寿命。金属材料表面纳米化是指利用反复剧烈塑性变形让表层粗晶粒逐步得到细化,材料中形成晶粒沿厚度方向呈梯度变化的纳米结构层,分别为表面无织构纳米晶层、亚微米细晶层、粗晶变形层和基体层,这种独特的梯度纳米结构对金属材料表面性能的大幅度提升效果显著。根据国内外表面纳米化的研究成果,首先对表面涂层或沉积、表面自纳米化以及混合纳米化3种金属表面纳米化方法进行了简要概述,阐述了各自优缺点,总结了表面自纳米化技术的优势,在此基础上重点分析了位错和孪晶在金属材料表面自纳米化过程中所起的关键作用,提出了金属材料表面自纳米化机制与材料结构、层错能大小有着密不可分的联系,对金属材料表面自纳米化机制的研究现状进行了归纳;阐明了表面纳米化技术在金属材料性能提升上的巨大优势,主要包括对硬度、强度、腐蚀、耐磨、疲劳等性能的改善。最后总结了现有表面强化工艺需要克服的关键技术,对未来的研究工作进行了展望,并提出将表面纳米化技术与电镀、气相沉积、粘涂、喷涂、化学热处理等...     

New Developments in Thermo-Chemical Diffusion Processes

Thermo-chemical diffusion processes like carburising, nitriding and boronizing play an important part in modern manufacturing technologies. They exist in many varieties depending on the type of diffusing element used and the respective process procedure. The most important industrial heat treatment process is case-hardening, which consists of thermochemical diffusion process carburising or its variation carbonitriding, followed by a subsequent quench. The latest developments of using different gaseous carburising agents and increasing the carburising temperature are one main area of this paper.The other area is the evolvement of nitriding and especially the ferritic nitrocarburising process by improved process control and newly developed process variations using carbon, nitrogen and oxygen as diffusing elements in various process steps. Also boronizing and special thermo-chemical processes for stainless steels are discussed.     

Properties and Structure of AlZnMg/Steel Fibre Composite Material

Editorial Note and Synopsis

This paper does not fall within the usual strict definition of cast metals science and technology, since it is concerned with a wholly solid-state process. It has, however, been accepted for publication in Cast Metals, since its treatment of the influence of fibre reinforcement on mechanical properties of a light alloy is considered to be pertinent to the growing understanding of the behaviour of composites, whether wrought or cast, as a major group of essentially new materials.

In this paper, the author examines the properties of a composite material with a matrix of hardenable AlZn4Mg1 alloy, reinforced by maraging steel fibres. For the purpose of the investigation the material was produced from layers of steel reinforcement fibre, interleaved with aluminium foil, which were subsequently hot pressed under vacuum. It was found that the presence of reinforcement fibres increased the strength by approximately twice the initial value. Nevertheless, the theoretical strength and Young's Modulus were about 15% higher than the values obtained. This was thought to be due to the considerable heterogeneity of the matrix. The reinforcement steel exhibited plastic behaviour, the matrix condition depending on the type of ageing. The diffusion layer on the fibre surface exhibited brittle fracture.     

Special features of oxygen distribution in the surface region of steel IOKhN2 under the effect of gas-discharge plasma

In recent years technological processes and methods of treatment that include the use of low-temperature gas-discharge plasma have become very popular. Ion-plasma technologies are used successfully for cleaning the surface of materials or creating thin-film structures and coatings and for chemicothermal treatment (nitriding, siliconizing, boronizing, carburizing, etc.) of various metals and alloys. The effect of the plasma of a gas glow discharge on a solid body can be manifested in a change in the chemical composition of its surface region. This is caused by the introduction of elements from the gas atmosphere into the specimen and by the redistribution of the matrix components in this region. The nature of such a redistribution of the components under the action of a gas-discharge plasma is not completely clear, which, among other reasons, is associated with the insufficiency of experimental and theoretical data on the problem. The present work concerns the causes and possible mechanism of the appearance of an oxygen-rich layer in the near-surface region of steel 10KhN2 after the action of a glow-discharge plasma in He, N₂ + 25% H₂, and Ar atmospheres. A correct explanation of this phenomenon can have a decisive role in understanding the special features of the diffusion processes occurring in a solid body under the effect of a gas-discharge plasma.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 4, pp. 26 – 28, April, 1996.     

表面微织构协同热扩渗技术改善材料表面摩擦学性能的研究进展

表面微织构因其能够有效改善摩擦副之间的摩擦学性能而获得国内外学者的广泛关注。通过将表面微织构与热扩渗技术相结合,可以充分发挥2种技术的优点,进一步提高摩擦副之间的摩擦学性能,为更复杂环境下的应用提供可能。首先概述了表面微织构的常用加工方法及其所加工的织构类型,系统地归纳总结了表面织构在不同润滑工况下的减摩机理。其次,从不同的表面热扩渗技术入手,分别综述了盐浴渗氮技术、等离子渗镀技术、热氧化技术和化学气相沉积与表面织构的协同作用研究现状,根据摩擦因数、磨损量和表面硬度等性能参数,分析总结了不同复合技术的可行性以及对基体摩擦学性能的影响。相对于单一表面处理技术,复合技术能够进一步提高材料的表面硬度,延长织构的使用寿命。一般来说,复合处理表面的耐磨性显著优于单一技术处理的表面和未处理表面,但摩擦因数受工况的影响较大。最后,对该复合技术的研究发展做出总结,提出不同织构参数和热扩渗参数对基体摩擦磨损性能的影响有待进一步探究,开展极端工况下复合技术的应用基础研究,推动复合技术在摩擦领域的发展。     

高强度汽车齿轮表面强化技术的研究现状和发展趋势

齿轮的强度和使用寿命是制约我国汽车及其他高端机电装备国产化的重要因素。根据近年来国际上高强度汽车齿轮研究与应用成果表明,表面强化技术已经成为实现高强度齿轮的疲劳极限、疲劳耐久寿命和最佳摩擦因数等高性能要求的核心技术。尤其是对齿轮主要材料中合金成分影响和齿轮弯曲疲劳和接触疲劳破损机理的研究、开发齿轮的汽车齿轮渗碳和碳氮共渗等热处理新技术、以及强力喷丸、微粒喷丸、复合喷丸、磷酸锰转化涂层、二硫化钼与微粒子复合喷涂等表面强化等新技术都越来越受到到国内外的重视。文中根据表面强化技术的最新研究现状,重点论述了齿轮在应用中经常出现的主要损伤形式以及最新的防止损伤的一些表面强化新技术,阐述了这些新技术的表面强化机理和应用效果;同时分析了高强度齿轮表面强化技术面临的问题和发展趋势。     

金属表面自纳米化及其复合改性技术研究进展

结合国内外表面自纳米化的研究成果,综述了表面纳米晶层产生的机理及表面自纳米化对材料表面硬度、摩擦磨损性能、抗疲劳性能以及耐腐蚀性能等的影响,总结了表面纳米晶层的优势,并针对表面纳米晶层性能及单一表面处理技术的不足,详细介绍了金属表面自纳米化与等离子体扩渗、微弧氧化及化学镀等常规表面处理相结合的复合改性技术研究进展,阐明了复合处理技术在材料性能提升上的巨大优势。最后,指出了复合处理技术面临的挑战,并从加强作用机理的研究、复合处理工艺系统性研究以及推进工业化应用等方向着手,提出应充分发挥金属材料表面自纳米化这一普适性的表面处理手段与其他表面改性技术复合的优势。希望为实现金属材料结构功能一体化,促进高性能新型材料和高性能复相表层的研究开发,加快复合改性技术工业化应用的进程提供借鉴与支撑。     

纯钛表面渗Mo改性层在模拟人工体液中的腐蚀行为研究

为了提高纯钛表面的耐磨性,并检测改性层在模拟人工体液中的耐蚀性能,利用等离子表面合金化技术在纯钛表面渗Mo,对改性层的组织、成分进行测试,并对其在模拟人工体液中的耐蚀性进行了研究.结果表明:表面改性层由渗层及扩散层组成,改性后的钛材不但表面硬度显著提高,在模拟人工体液中的耐蚀性也得到改善.