γ射线辐照－水热处理法制备纳米金属粉末SCIEI

用γ射线辐照－水热处理法制备出８ｎｍＡｇ粉、１６ｎｍＣｕ粉和１０ｎｍＰｄ粉．研究了实验条件对Ａｇ粉粒径的影响．确定了制备纳米Ｃｕ粉的工艺参数，发现用ＥＤＴＡ络合Ｃｕ离子，有利于制备粒径较小的纳米Ｃｕ粉，在不同条件下可获得球形和针形的纳米Ｃｕ粒子．     

PREPARATION OF NANOCRYSTALLINE METAL POWDERS BY γ-IRRADIATION-HYDROTHERMAL TREATMENT METHOD

用γ射线辐照－水热处理法制备出８ｎｍＡｇ粉、１６ｎｍＣｕ粉和１０ｎｍＰｄ粉．研究了实验条件对Ａｇ粉粒径的影响．确定了制备纳米Ｃｕ粉的工艺参数，发现用ＥＤＴＡ络合Ｃｕ离子，有利于制备粒径较小的纳米Ｃｕ粉，在不同条件下可获得球形和针形的纳米Ｃｕ粒子．     

γ射线辐照－水热处理法制备纳米金属粉末

用γ射线辐照－水热处理法制备出８ｎｍＡｇ粉、１６ｎｍＣｕ粉和１０ｎｍＰｄ粉．研究了实验条件对Ａｇ粉粒径的影响．确定了制备纳米Ｃｕ粉的工艺参数，发现用ＥＤＴＡ络合Ｃｕ离子，有利于制备粒径较小的纳米Ｃｕ粉，在不同条件下可获得球形和针形的纳米Ｃｕ粒子．     

碳化钨—钴纳米复合材料合成的新方法

ＷＣ－Ｃｏ纳米复合材料的合成通常都包括气相碳化。开发了一种采用聚丙烯晴之类的原始聚合物作为原位碳源的新方法。生成的ＷＣ－Ｃｏ纳米复合材料用Ｘ－射线能谱和衍射法和电子显微镜法进行了鉴定。制取了颗粒度５０￣８０ｎｍ 的接近于相纯的ＷＣ－Ｃｏ纳米复合材料。产物的相纯度受煅烧温度、时间和气氛等合成和处理条件的强烈影响。     

含纳米粉镀液的电刷镀复合镀层试验研究

应用电刷镀技术制备了含有纳米ＳｉＣ粉的镍基复合镀层,对该复合镀层的显微硬度和摩擦学性能进行了测试,并讨论了主要工艺参数对这些性能的影响规律。测试结果表明：纳米ＳｉＣ粉的加入可以一定匠提高复合镀层的硬度。快镍复合纳米ＳｉＣ镀层的２因氏于快镍镀层的摩擦因数。镀液中纳米ＳｉＣ粉和添加剂浓度增加时,复合镀层的摩擦因数低于快镍镀层的摩擦因数。镀液中纳米ＳｉＣ粉和添加剂的提高。还采用光学显微分析（ＯＭ）和电子     

纳米晶Cu30Al70合金的形成及其催化活性

本文利用机械球磨的方法将工业上广泛应用的传统的ＲａｎｅｙＣｕ催化剂的前体Ｃｕ３０Ａｌ７０合金制成了纳米晶合金催化材料，并研究了它在木糖加氢反应中的催化活性。结果表明，制成的纳米晶合金ＣｕＡｌ２相的平均晶粒尺寸为１２ｎｍ，球料比和球磨时间极大地影响形成的纳米晶Ｃｕ３０Ａｌ７０合金的晶粒尺寸，纳米晶Ｃｕ３０Ａｌ７０合金组织较均匀，元素分布均匀，活化后的催化剂具有较高的催化活性。     

纳米晶Cu_30Al_70合金的形成及其催化活性

本文利用机械球磨的方法将工业上广泛应用的传统的ＲａｎｅｙＣｕ催化剂的前体Ｃｕ３０Ａｌ７０合金制成了纳米晶合金催化材料，并研究了它在木糖加氢反应中的催化活性．结果表明，制成的纳米晶合金ＣｕＡｌ２相的平均晶粒尺寸为１２ｎｍ，球料比和球磨时间极大地影响形成的纳米晶Ｃｕ３０Ａｌ７０合金的晶粒尺寸，纳米晶Ｃｕ３０Ａｌ７０合金组织较均匀，元素分布均匀，活化后的催化剂具有较高的催化活性．     

纳米结构碳化钨／钴粉末的开发和应用

改善机械性能的潜在利益继续推动着超细显微结构硬质合金材料的研究。目前尚在开发阶段的烧结新技术正开始利用纳米结构ＷＣ－Ｃｏ粉末的优势，有望将烧结颗粒的平均粒度减小到１００ｎｍ以内。完全纳米结构的ＷＣ－Ｃｏ硬质合金还有待努力，但是第一步已就位，即纳米结构粉末的生产。这种粉末的商业化生产运用了喷射转变工艺，制得的粉末由弥散于金属粘结相的２０￣５０ｎｍ，ＷＣ颗粒组成。这些小ＷＣ颗粒比应用传统碳化工艺制得的     

纳米晶Al88Ce2Ni10铝合金的形成

通过晶化法，可以将快凝Ａｌ８８Ｃｅ２Ｎｉ１０非晶铝合金制备成纳米晶合金。纳米晶合金的组织为αＡｌ固溶体和金属间化合物Ａｌ３Ｎｉ及Ａｌ１１Ｃｅ３组成的多相纳米晶结构。在６０３～７７３Ｋ较宽退火温区内，用Ｓｃｈｅｒｅｒ公式计算各晶化相，得到αＡｌ、Ａｌ３Ｎｉ及Ａｌ１１Ｃｅ３的晶粒尺寸分别为３１～３１６、２２～２０７及１９～１６５ｎｍ。结果表明，通过控制热处理条件，可以获得不同晶粒尺寸的纳米晶合金。其中获得晶粒细小、结构均匀超细纳米晶合金的最佳退火温度为第二ＤＳＣ峰值温度附近     

机械合金化形成的Fe—Cu纳米晶过饱和固溶体的硬化及软化

用机械合金化方法，在不互溶的Ｆｅ－Ｃｕ二元系的富Ｆｅ端和富Ｆｅ端和Ｃｕ端，分别制备出ｂｃｃ和ｆｃｃ结构的纳米晶过饱和固溶体，用Ｘ射线衍射和显微硬度分析等方法，系统研究了晶粒尺寸，溶质原子含量等因素对Ｆｅ－Ｃｕ纳米晶过饱和固溶体硬度的影响。结果表明，在富Ｃｕ端形成的ｆｃｃ纳米晶过饱和固溶体的硬度、随溶质原子Ｆｅ含量的增加而升高，而在富Ｆｅ端形成的ｂｃｃ纳米晶过饱和固溶体的硬度，随溶质原子Ｃｕ量的增加     

The Influence of Pre-Plating Processes on the Porosity of Electrodeposits on Steel

The electrochemical method of obtaining a numerical index of the porosity of electrodeposits, previously described by the authors, has been applied to a study of the effects of pre-plating preparation of steel. Five different rolled steels and coatings of nickel, tin-nickel, tin and speculum were examined. The validity of the test method has been verified by comparison with laboratory and exposure tests yielding visual indications of porosity. It was found that the depth of steel removed by any method of pre-plating preparation had an influence on the porosity of the coating sufficiently large to obscure, if it were not controlled, effects of difference in preparation method. The removal of the extreme surface layer of steel (about 0·00001 in) influences the porosity of the applied coating for better or worse according to the metal deposited and the conditions of deposition. Evidence was obtained that this effect depends on the form of crystal growth of the deposit. With deeper uniform penetration into the steel, zones were reached which were apparently features of the steel and influenced porosity almost independently of the character of the deposit. These zones are attributed to bands of nonmetallic inclusions. The observed effect of depth of penetration helps to explain the divergent results previously obtained in investigations of surface preparation. It suggests that, in practice, when controlled penetration cannot be expected, no method of surface preparation will give consistent porosity of deposits on a range of steels. The response of an undercoating to the condition of the steel surface was found to govern the porosity of a composite coating. Well-chosen undercoatings may therefore offer the best method of obtaining consistent results and of reducing porosity.     

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.     

Modeling of structure of double-phase low-carbon chromium steels

A physical model for determining the relative amount of phase components and the size of ferrite grains after decomposition of austenite in the process of cooling of double-phase steels is suggested. The main products of austenite transformation, i.e., polygonal ferrite, pearlite, bainite, and martensite, are considered. The driving forces of the transformation and the concentration of carbon on the phase surface are determined with the use of methods of computational thermodynamics. The model is based on equations of the classical theory of nucleation and growth. It allows for the structural features of the occurrence of γ → α transformation and contain some empirical parameters. The latter are determined using data of dilatometric measurements of the kinetics of austenite transformation and metallographic measurements of the size of ferrite grains. The model is used for predicting the kinetics of the transformation under the complex cooling conditions implemented by the VOEST-ALPINE STAHL LINZ GmbH rolling mill within the computer system for control of mechanical properties of hot-rolled strip.     

Effect of reversibility of structure and properties in hydrogen charging of carbon steel and influence of hydrogen on formation of electrodeposited zinc coatings

Specimens of steel 70 are studied before and after alkaline galvanizing and after galvanizing and partial dehydrogenizing. The content of hydrogen and its distribution between the coating and the substrate are estimated. The structures of the substrate metal and of the coating are studied before and after dehydrogenization. Mechanical tests at various rates of deformation of specimens of steel 70 in different initial states are performed. The tests are followed by an analysis of fracture surfaces. The effect of hydrogen on the fracture behavior is evaluated at different rates of deformation of specimens. The effect of reversibility of the structure and properties in “hydrogen charging-dehydrogenization” of the steel is determined and the mechanism of formation of a layered structure of zinc coatings is described.     

Simulating convection and macrosegregation in superalloys

Numerical simulations using a mathematical model of the dendritic solidification of multicomponent alloys that includes thermosolutal convection and macrosegregation were conducted on nickel-based alloys. The results show that segregation patterns vary greatly with cooling conditions, adopting several shapes and levels of intensity. In addition, the segregation patterns are particularly sensitive to the values of the equilibrium partition coefficients of the alloy components. S.D. Felicelli earned his Ph.D. in mechanical engineering from the University of Arizona in 1991. He is currently a research scientist at Centro Atomico Bariloche, Argentine Atomic Energy Commission. D.R. Poirier earned his Sc.D. in metallurgy from the Massachusetts Institute of Technology in 1966. He is currently professor of materials science and engineering at the University of Arizona. Dr. Poirier is a member of TMS. A.F. Giamei earned his Ph.D. from Northwestern University in 1967. He is currently principal scientist in the Materials and Structures Technology Department of the United Technologies Research Center. Dr. Giamei is also a member of TMS. J.C. Heinrich earned his Ph.D. in mathematics fromthe University of Pittsburgh in 1975. He is currently professor of aerospace and mechanical engineering at the University of Arizona.     

Effect of vacuum arc and electroslag remelting on the anisotropy of the properties of structural steels

Conclusions o 1.Melting steel by the ESR and VAR methods, and combination of the two, substantially increases the plasticity and ductility of structural steels 18Kh2N4VA, 40KhNMA, and 35Kh2GSMA both in the longitudinal and, particularly, the transverse directions. 2.ESR and VAR substantially reduce the coefficient of anisotropy of the impact toughness and the specific reduction in section. The higher the anisotropy of the original open-hearth melt, the greater the effect. 3.The effectiveness of these new melting methods in reducing the coefficient of anisotropy of the plasticity and ductility of structural steels is due directly to purification; the removal of nonmetallic inclusions, especially sulfides.The use of a combination of ESR and VAR does not lead to any further reduction of the anisotropy coefficient. 4.The anisotropy coefficient of the impact toughness does not depend on the value of the strength. The anisotropy coefficient of the specific reduction in section for the steel tempered at high temperature is lower than for the steel quenched and tempered at low temperature. 5.The use of these new melting methods leads to an increase of the cold resistance.Scientific Research Institute of Metallurgy, Chelyabinsk Metallurgical Plant. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 2, pp. 41–44, February, 1968.     

The Physical Origin of Anomalous Scattering

Owing to the availability of synchrotron radiation, anomalous scattering of X-rays plays an increasing role in crystallography. This makes full understanding of the underlying principles necessary. The first part of the article explains anomalous scattering in terms of the classical theory of scattering by a damped oscillator. The damping accounts for the action of the emitted radiation on the oscillator itself. It causes a phase shift with respect to the motion of an undamped oscillator. This phase shift is the characteric of anomalous scattering and is represented by adding an imaginary component to the real scattering factor. The relations to the macroscopic index of refraction and the absorption coefficient are discussed. To bridge the gap between classical and quantum theory, the harmonic oscillator model is explained in terms of atomic wave functions and their deformation under influence of the electric field. The nonrelativistic quantum theoretical treatment of X-ray scattering is based on perturbation theory whereby use is made of Feynman-type diagrams and their mathematical translations. The origin of Thomson and Rayleigh scattering are given. The second one is characterized by virtual transitions to intermediate states. When the incident radiation corresponds with an absorption edge, the virtual transitions become real ones and decay of the intermediate state sets in. This decay leads to a phase shift of the probability amplitude of the path, the quantum mechanical equivalent of the scattering factor. The relation between the position of the target and the phase of the scattered beam is a matter of convention. This convention also dictates the sign of the phase shift mentioned above. Mathematical tools and detailed derivations are given in an appendix.     

Teil II: Biokorrosive Ursachen der Glaspestbildung an Mecklenburger Waldgläsern

Biodeterioration on oxidic glasses - Part II: Biocorrosive reasons for appearance of Glaspest of antique glasses like Mecklenburger Waldglas Glaspest is a consequence of biodeterioration. It is a barrier of diffusion, which prevents the corrosion of the motherglass.The appearance of Glaspest is caused by the output of organic acids by fungi. In this case Alternaria, Aspergillus and Penicellium and other were found. Organic acids, produced in culture filtrates of these fungi, were analysed by High Performance Liquid Chromatography (HPLC). Acetic acid, oxalic acid, citric acid, gluconic acid and finally fumaric acid were identified as the corrosive media. Laboratory experiments with glass powder and organic acids show a close relation between the microbiological attack and the appearance of the Glaspest layer, in particular whedellite is a consequence of the attack of oxalic acid. Experiments with culture filtrates indicate an increase of pH. Alkaline oxides are dissolved and can attack the glass network, quartz nascents. At last Glaspest can be reproduced by fungi settlement at model glasses. All these results indicate the presence of a three-phase-model mechanism of biodeterioration on glass, especially for glasses with a high amount of alkaline oxides. The first phase is the phase, in which micro-organisms colonialize the glass surface. Then the output of organic acids starts, followed by a neutralisation of alkaline oxides of the glass volume. The result of this phase is the appearance of Glaspest. At the second phase dissolved alkaline oxides attack the Glaspest, pH increases and quartz appears. During the constant attack of oxalic acid whedellite emergence. The last phase is a passive one. Whedelitte converts to calcite in the presence of water and carbon dioxide.     

Grain boundary misorientation effects on creep and cracking in Ni-based alloys

The effect of altered grain boundary character distributions on the creep and cracking behavior of polycrystalline Ni-16Cr-9Fe at 360°C was studied by comparing the creep and intergranular cracking behavior of solution-annealed material containing mostly high-angle boundaries to material that was thermomechanically processed to enhance the proportion of coincident-site lattice boundaries. In parallel with mechanical testing, the modification of dislocation structures in the grain boundary resulting from reactions with run-in lattice dislocations was studied using transmission electron microscopy. Observations were concerned with the ability of grain boundaries to act as sinks for lattice dislocations in which the kinetics depend on the grain-boundary structure. A mechanism based on dislocation annihilation was proposed to account for the observed effect of the coincident-site lattice boundaries on creep. Gary S. Was earned his Sc.D. in nuclear materials at the Massachusetts Institute of Technology in 1980. He is currently a professor and chair of the Department of of Nuclear Engineering and Radiological Sciences at University of Michigan. Dr. Was is a member of TMS. Visit Thaveeprungsiporn earned his Ph.D. in nuclear engineering at the University of Michigan in 1966. He is currently a lecturer in the Department of Nuclear Technology, Faculty of Engineering at Chulalongkorn University, Thailand. Dr. Thaveeprungsiporn is also a member of TMS. Douglas C. Crawford earned his Ph.D. in nuclear engineering at the University of Michigan in 1991. He is currently department manager of fuels technology in the Engineering Division at Argonne National Laboratory.     

Structure and hydrogen sorption properties of (Ti,Zr)–Mn–V alloys

The present investigation is a part of the series of works on the development of new materials as highly efficient hydrogen accumulating media. Earlier we reported on the investigation of Ti–Mn–V alloys of Laves phase type. This work is the continuation of these studies. The work was aimed on the determination of concentration boundaries of Laves phase and investigation of hydrogen sorption properties of alloys. Using X-ray, EDXA and electron microscopy methods the phase compositions of over 50 alloys were studied. The Laves phase concentration boundaries were determined to extend up to 26 at.% of vanadium. Compared to ternary Ti–Mn–V system the region of λ₁-phase is about 2 at.% wider for Ti–Mn side of concentration triangle. Depending on metal concentrations lattice parameters were determined to increase proportionally with increasing titanium or vanadium concentration according to Vegard rule. The interaction of alloys with hydrogen was studied by PC-isotherm method. The isotherms were measured at three different temperatures and thermodynamic parameters of reaction were calculated using the vant Hoff equation. The hydrogen sorption properties were analysed in view of overall alloy composition. The enthalpy of desorption was found to depend proportionally on unit cell volume of alloy.