FeCrAIW电弧喷涂层组织的致密化研究

采用激光辐照对FeCrAlW电弧喷涂层的组织进行致密化处理,借助扫描电镜和X衍射对涂层的组织进行了分析.测试了涂层的显微硬度.结果表明:涂层组织致密度提高,孔隙率明显降低.随着激光扫描速度的增加,涂层的显微硬度降低.在较低的扫描速度下,涂层与基体之间形成互熔区,涂层与基体之间产生良好的冶金结合.     

胫骨生物陶瓷复合材料的微结构增韧机理

扫描电镜观察显示胫骨是一种由羟基磷灰石和胶原蛋白组成的自然生物陶瓷复合材料.羟基磷灰石具有层状的微结构并且平行于骨的表面排列.观察也显示这些羟基磷灰石层又是由许多羟基磷灰石片所组成,这些羟基磷灰石片具有长而薄的形状,也以平行的方式整齐排列.基于在胫骨中观察到的羟基磷灰石片的微结构特征,通过微结构模型分析及实验,研究了羟基磷灰石片平行排列微结构的最大拔出能.结果表明,羟基磷灰石片长而薄的形状以及平行排列方式增加了其最大拔出能,进而提高了骨的断裂韧性.     

国内钨精矿市场价格振荡原因分析

介绍了国内外钨精矿资源分布情况,分析了近阶段价格波动原因及后期走势。     

飞机水平安定面后梁中段裂纹原因分析

在使用过程中,飞机水平安定面后梁中段出现裂纹。通过宏微观形貌观察、微区成分分析、金相检查和硬度测试,确定了水平安定面后梁中段的裂纹性质及失效原因。结果表明:后梁中段裂纹性质为剥层腐蚀裂纹,水平安定面后梁中段铆钉区腹板与后梁下缘条之间以及凸台与机身之间发生磨损导致剥层腐蚀裂纹。建议水平安定面后梁中段铆钉区腹板与后梁下缘条之间以及凸台与机身之间连接增加垫片,防止直接接触,并且对材料进行表面防护。     

面向零件形状的计算机图形库的开发

论述了CAD技术中参数化设计的三种建模方法，重点介绍了基于特征的参数化建模原理。在此基础上，分析机械设计中的机构结构，归纳出其零件的几何特征构成。设计了机构CAD图形库，并提出了该图形库生成步骤和人机交互界面。     

Analysis of microporous structure of carbon adsorbents in terms of the theory of volume filling of micropores

A methodology of using the theory of filling the volume of micropores when evaluating the porous structure of carbon nanomaterials and adsorbents, as well as describing the adsorption of different species, is considered. Potentialities of the mathematical means of a theory of filling the volume of micropores when differentiating homogeneous and irregular microporous structure of activated carbon, determining the micropores’ parameters (their volume and size), evaluating the degree of heterogeneity of microporous structures, and describing adsorption over wide concentration range are analyzed. The perspectives of this approach, based on the theory of filling the volume of micropores, in the prognosis of the microporous structures’ parameters and the activated carbons’ adsorbability in the process of their synthesis are demonstrated. Original Russian Text ? G.A. Petukhova, 2008, published in Zashchita Metallov, 2008, Vol. 44, No. 2, pp. 170–176.     

Modelling of processes of thermochemical treatment of metals: traditions of Russian scientific school

Abstract

The paper is devoted to 100th anniversary of the outstanding Russian scientist professor Yuriy Mikhailovich Lakhtin – the founder of the world-famous scientific school of surface strengthening of metals and alloys. Lakhtin's scientific school is recognised for its contribution into research of processes of thermochemical treatment of metals and especially of nitriding. Today at the Department of Metal Science and Heat Treatment of MADI his followers continue the traditions of Lakhtin's scientific school. The development of technologies of surface engineering is based on complex modelling of physical processes realised by thermochemical treatment of metals. Thermodynamic models describe the interaction between metals and components of saturating atmosphere and predict phase composition of diffusion layer. Diffusion models of kinetics of saturation of metals allow us to calculate the rate of growth of diffusion layer and regulation of its depth and structure. Structural models determine quantitative dependence between parameters of structure (grain size, dispersed particles, etc.) and mechanical properties. These models allow us to estimate the level of strengthening by control of structural specifics of strengthened layer. On the basis of this complex of models, new efficient technologies of surface strengthening are developed.     

钢材打捆机控制系统智能化技术的研究

钢材打捆机是一种用于轧钢精整工艺的新型自动化设备，其控制系统基于SiemensS7 PLC和TP7触摸屏。系统的智能化技术主要包括：液压高低压自动控制、在线监视、离线故障检测、多台设备协同工作、可视化人机交互技术。本文描述了这些技术的原理与实现方法。     

履带拖拉机再制造工程的质量体系及效益分析

阐述了农用履带式拖拉机再制造工程的可行性和前景。介绍了农用履带拖拉机实施再制造的工艺流程及质量保证体系。分析了农用履带拖拉机实施再制造的经济效益和社会效益。提出了推动农用拖拉机再制造应当解决的问题。通过对128台旧拖拉机的统计，可以直接再使用的零件和可以用新工艺、新技术修复和改造的零件占全车零件总数的60．72％，占全车重量的61．55％，占全车总价值的60．76％。而再制造拖拉机的售价仅为新机的50％－60％，寿命接近新机的80％。说明了实施拖拉机 再制造工程在节约钢材、能源，保护环境等方面的重要作用。     

Optimization of the profile of axisymmetric components of nozzles

A mathematical model of a turbulent boundary layer, describing the non-stationary non-isothermal flow of an incompressible gas in axisymmetric channels with the heat exchange is constructed. The equations of motion, continuity, and energy; the closing relationships for the coefficients of friction; and the heat transfer at the appropriate boundary conditions can be used for the analysis of the effect on the processes of friction and heat transfer with subsequent synthesis of phenomena – investigation of their combined effect and the determination of correlations between them, together with optimization of the profile of the surface with the flow around from the viewpoint of minimizing the thermal loading and energy dissipation.     

高等教育国际化与中国高等教育施化力培育

本文从化层、化型、化向与化力等方面考察高等教育国际化的应然本质属性 ,描述与分析中国高等教育在国际化潮流中表现出的发展态势 ,针对种种态势提出中国高等教育核心施化力培育战略 ,以使中国高等教育乃至世界高等教育真正地走向国际化     

Features of formation of the structure in production of blanks of disks of heat-resistant nickel alloys

Conclusions To provide a high level of mechanical properties in wrought blanks of cast ÉP741NP and ÉP962 alloys it is necessary to form controlled structures. A necklace-type structure formed in homogenizing isostatic treatment, subsequent thermomechanical working including alternation of the operations of deformation in the (+)-area and recrystallization anneals, and final heat treatment is preferable. The temperature conditions of all stages of thermomechanical working are strictly controlled, especially the final operation of deformation and heating for hardening. To eliminate hardening cracks and distortions it is necessary to use molten salts at t=600°C as quenchants. The use of multiple production operations makes it possible to significantly reduce the structural inhomogeneity related to inhertance of the original dendritic structure. However, the structure of the final semifinished product is nevertheless characterized by a difference in occurrence of the processes of polygonization and recrystallization between the former dendritic cells and the interdendritic spaces in deformation and heat treatment.To obtain structurally homogeneous blanks for gas turbine engine parts it is necessary to use basically new methods of remelting such as vacuum double electrode remelting and electron beam remelting with an intermediate vessel.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 12, pp. 25–29, December, 1991.     

Calculation of thermodynamic properties of metastable phases of the elements

A chemical bonding model that provides a method of predicting thermodynamic properties of metastable structures of the solid elements is presented. The method involves a Born-Haber-type cycle to calculate the difference in bonding energies between the room temperature stable structures and metastable structures. To carry out the calculations, spectroscopic data are used to determine the promotion energies from the ground state of the gaseous atom to the valence state corresponding to each structure. Such data are available for most elements, but in cases where experimental data are lacking, they are derived using predictive models. Combinations of promotion energies and heats of sublimation are used to determine bonding enthalpies. The contribution of the outer-shell s and p-electrons and the inner-shell d and f electrons to the bonding energies are considered taking into account the crystal field effect upon the bonding abilities of different d and f orbitals This paper was presented at the Thermodynamics and Phase Equilibria of Metastable Phases Symposium at the Spring TMS Meeting, March 1-4, 1992, in San Diego. The symposium was organized by Philip Nash, Illinois Institute of Technology, and Ricardo Schwarz,Los Alamos National Laboratory.     

Peculiarities of Electrochemical Behavior of Porous Carbon Electrodes of Supercapacitors in Aqueous Solutions of Salts of Alkali Metals

Electrochemical behavior of porous carbon electrodes with different densities (0.75 and 0.35 g/cm³) used in supercapacitors with aqueous solutions of lithium, sodium and potassium sulfates was studied. It was shown that Li₂SO₄ solution is the most suitable for high-density electrodes, whereas K₂SO₄ solution is better for low-density electrodes. Experimental data obtained by means of cyclic voltammetric and impedance curves demonstrate a mutual influence of the porous structure of the electrode materials and diameters of solvated and bare ions on the values of specific capacitance and resistance. This should be taken into account when an electrode/electrolyte system is chosen for high-efficiency energy storage devices.     

电磁成形技术理论研究进展

介绍了国内外电磁成形理论研究概况及进展,总结了研究成果和特点,讨论了电磁成形中高速率变形条件下材料成形性提高的决定因素。对电磁成形理论研究的发展趋势进行了展望。     

Evolution of misorientation spectrum of grain boundaries of submicrocrystalline molybdenum upon deformation under conditions of grain-boundary diffusion of nickel

Comparative investigations of the concurrent evolution of the structure and the misorientation spectrum of grain boundaries of submicrocrystalline molybdenum have been performed upon free annealing and under the creep conditions at a temperature of 1023 K. It has been established that changes in the misorientation spectrum of grain boundaries of submicrocrystalline molybdenum upon annealing and creep are observed concurrently with boundary migration. The grain-boundary diffusion of nickel upon annealing leads to an increase in the fraction of grain boundaries of the special type with Σ17a in the grain-boundary ensemble of submicrocrystalline molybdenum. Under the creep conditions grain-boundary diffusion fluxes of nickel atoms favor transformation of low-angle boundaries into high-angle boundaries and growth in the angle of misorientation of the high-angle boundaries of submicrocrystalline molybdenum to 45°–60°.     

棒材轧制中头尾尺寸缺陷的消除

针对陕西龙门钢铁集团有限责任公司西安轧钢厂半连续棒材线生产过程中出现的头尾尺寸缺陷问 题,从工艺、机械、电气、操作四方面进行了分析,并通过改进精轧K3、K5孔型和导卫系统,增加精轧4#活套,改造自动化和传动系统,解决了大头大尾或无纵筋的问题,提高了成材率。     

钢管穿孔机主减速机振动分析

宝山钢铁股份有限公司钢管分公司的穿孔机下辊主减速机在大定修前,减速机轴和下辊大电机的振动情况严重,诊断部门对该减速机进行了测振分析,结合对电机振动、减速机振动的频谱分析和对轴承的故障频率成分分析,找出了主减速机振动的原因是轴承损伤。该分析结果与解体检查的结果相一致。     

Current state of the theory of age-hardening of metallic alloys

Conclusion In recent years we have produced new types of age-hardening alloys and new hardening treatments for which the combination of several methods of hardening is typical. We should note first of all the high-nickel and chromium-nickel maraging steels and various methods of thermo-mechanical treatment for age-hardening alloys. In all cases the decomposition processes involve a high density of structural defects. Explanation of the decomposition mechanism in connection with specific types of defects is an urgent problem, the solution of which is already possible with present techniques of electron microscopy (crystallographic analysis of structural defects and new formations is possible with the use of goniometric devices in transmission electron microscopy).Further development of mathematical methods is needed for investigating phase transformations in alloys and refining the quantitative theory of the processes of precipitation and coalescence used for present-day multicomponent alloys and combined treatment.The major problem in this area of metal science is to obtain more complete characteristics of the structure of the material in the state of maximum hardness and establish quantitative relationships between the structural and strength characteristics.Moscow Institute of Steel and Alloys. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 5, pp. 26–40, May, 1967.     

钽薄板TIG焊接电弧形态的研究

通过高速摄像方法研究了钽薄板TIG焊接过程中，保护气体及工艺参数不同时电弧形态的变化规律及其对焊接质量的影响。结果表明：保护气体不同时，电弧形态明显不同。采用TIG焊焊接钽板时使用氦弧能得到更好的焊接质量；当弧长不变，增加焊接电流时，电弧有效作用范围变犬，电弧温度及能量密度高。熔池增大速度较快；当焊接电流不变，弧长增加时，电弧有效加热半径变大，但由于弧长增加而引起电孤热能分散。熔池增长速度较慢，热影响区范围增大。焊接工艺参数的变化时电弧形态的影响规律，对制定钽薄板TIG焊接过程中较为合理的工艺参数具有重要意义。