Correlation between microstructure and mechanical behaviour at high temperatures of a SiC fibre with a low oxygen content (Hi–Nicalon)

An oxygen free Si–C fibre has been studied in terms of the chemical, structural and mechanical properties produced as a function of annealing treatments. In spite of its high thermal stability with regard to a Si–C–O fibre the Si–C fibre was subject to moderate SiC grain growth, organization of the free carbon phase and densification within the temperature range 1200–1400°C. The strength reduction at ambient for temperatures ≤1600°C could possibly be due to SiC coarsening or superficial degradation. Bend stress relaxation (BSR) and tensile creep tests show that the as-received fibre undergoes a viscous flow from 1000°C. The thermal dependance of the creep strain rate strongly increases at temperatures ≥1300°C. This feature might be partly explained by the structural evolution of the fibre occurring above this temperature. Heat treated fibres (1400–1600°C) exhibit a much better creep strength, probably due to their improved structural organization. This revised version was published online in November 2006 with corrections to the Cover Date.     

Efficiency of utilization of heat in the processes of convective drying and an equilibrium analysis

A method for evaluating the efficiency of convective dryers from the viewpoint of heat consumption has been proposed; the method is based on a comparison of the characteristics of the dryers to a standard: the process with an efficiency maximum possible under given conditions. The so-called equilibrium analysis assuming the absence of the internal heat and moisture gradients in the dried product is used. It has been shown that gradient-free processes limiting for all modes of phase contact with decrease in the drying intensity to zero possess the highest intensity. The basic rules of organization of economical drying have been formulated. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 81, No. 5, pp. 963–970, September–October, 2008.     

Effect of increased compacting pressures on the physicomechanical characteristics of metal-filled polyvinyl chloride

Based on the principles of linear thermodynamics, molecular physics, and spatial organization of amorphous polymers, the energy of formation of microdefects and the increments in their volumes as functions of the compacting pressure and the content of the filler of polyvinyl chloride systems are calculated. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 73, No. 4, pp. 807–812, July–August, 2000.     

From the European Group on Fracture to the European Structural Integrity Society

The first meeting of the European Group on Fracture took place at Université de Technologie de Compiègne in 1976. It was followed by more and more attended conferences every two years. The successive leaders strengthened the organization which became the European Structural Integrity Society in 1990. The ESIS is responsible for a number of activities, publications, technical committees, and the organization of conferences. They covered a number of topics which remained active throughout the years. In the future, it is recommended that the ESIS puts more emphasis on risk analysis and education. Laboratoire de Mécanique, CNPS URA 850, Ecole Centrale de Paris, Paris, France. Published in Fizyko-Khimichna Mekhanika Materialiv, Vol. 32, No. 5, pp. 14–18, September–October, 1996.     

Optimization of the process of continuous mass crystallization of salts from solutions

Crystallization of a polydisperse system of crystals in the case of continuous organization of the process in a cascade of crystallizers is investigated. The process is assumed to occur in a kinetic regime. The influence of fluctuations in the rate of crystal growth is taken into consideration. Basic computational formulas are obtained and certain limiting situations are analyzed. Russian Scientific Center “Applied Chemistry”, St. Petersburg, Russia. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 70, No. 5, pp. 707–713 September-October, 1997.     

Structure and electrochemical reactivity of new sulphur–silicon podands adsorbed on silver or gold surfaces

By the self-assembly monolayer (SAM) organization, three new podands belonging to silylpropanethiols have been tested as to their ability to form nanolayers protecting the noble metal surface (gold or silver) and to form complexes with monovalent metal cations on the metal surfaces. The stable self-assembled chemisorbed layers, providing protection to metal surface against electrooxidation and capable of blocking propylene carbonate (PC) electroreduction and Li electrodeposition were produced. Reflection-absorption infrared spectroscopy (RAIRS) indicated cleavage of the S–H bond upon adsorption of species 1–3 with the formation of S–Ag bonds on the metal surface. By cyclic voltammetry, it was found that the primary adsorbate formed on a Au electrode at E _ad (between −0.2 and −1.2 V vs. SCE) underwent reductive desorption at E < −1.3 V vs. SCE. The structures of 1–3 and their complexes with Na⁺ cations on the Ag surfaces were calculated and visualized by the AM1d semi-empirical method.     

Investigation of the dynamic properties of the cellular structure of a gas-detonation wave

The evolution of the cellular structure of a gas-detonation wave propagating in a circular pipe was investigated. The propagation regimes, hereafter ‘detonation modes,’ for which the organization of the flow in the detonation-wave front and, accordingly, the shape of the cellular structure have the best symmetry and recurrence, have been revealed. It is shown that the realization of only the single-mode regime of propagation is improbable and that the complete state of the wave-front structure as a function of time can be represented as a superposition of periodic functions corresponding to the states of neighboring detonation modes, and their normalized amplitude is proportional to the probability of the presence of the state of a given mode when a gas-detonation wave propagates. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 73, No. 5, pp. 932–938, September–October, 2000. This work was partly financially supported by the Fund for Fundamental Research of the Republic of Belarus, grant No. 98-196.     

Interdisciplinarity and the intellectual base of literature studies: citation analysis of highly cited monographs

This article studies interdisciplinarity and the intellectual base of 34 literature journals using citation data from Web of Science. Data from two time periods, 1978–1987 and 1998–2007 were compared to reveal changes in the interdisciplinary citing of monographs. The study extends the analysis to non-source publications; using the classification of monographs to show changes in the intellectual base. There is support for increased interdisciplinary citing of sources, especially to the social sciences, and changes in the intellectual base reflect this. The results are explained using theories on the intellectual and social organization of scientific fields and the use of bibliometric methods on the humanities is discussed. The article demonstrates how citation analysis can provide insights into the communication patterns and intellectual structure of scholarly fields in the arts and humanities.     

Results of participation of Russian standards in key comparisons conducted by the Regional Metrological Organization for countries of the Asia-Pacific Region in the field of liquid and gas flow rate parameter measurement

Results of international key comparisons of the national standard for air flow rate and the working standard for water volumetric and mass flow rate are provided. Comparisons were made in 2009 within the framework of the Asia-Pacific Metrological Program (APMP) international organization. Russia was represented by state special standard for the unit of air flow rate (GET 150–85) and the highest accuracy working standard for the unit of water volumetric mass flow rate (RE VT 6–98). Results of comparison point to conformity of the metrological properties of these standards to the world level.     

Measuring procedure in the course of sounding of objects and media by nuclear radiation

We give a survey of methods for organization of measuring procedure in the course of sounding of objects and materials by nuclear radiation. By using the model of measuring signal, we considered methods for selection, transmission, and processing of information. We give some examples of methods for estimation of the parameters of a signal of a detector of nuclear radiations of stationary, nonstationary, and random intensities as applied to a problem on distant sounding of media and materials by nuclear methods. The corresponding information measuring systems and methods for their metrological certification are presented. Karpenko Physicomechanical Institute, Ukrainian Academy of Sciences, L'viv. Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 33, No. 5, pp. 115–121, September–October, 1997.     

Subcritical crack growth and power law exponent of Y–Si–Al–O(–N) glasses in aqueous environment

The subcritical crack growth resistance in water of a Y–Si–Al–O and Y–Si–Al–O–N glasses has been investigated with three point bending experiments. It has been shown that the SCG behaviour of the Y–Si–Al–O–N glass is superior to that of the Y–Si–Al–O glass. This is reflected by the power law exponent n which is 21 for the Y–Si–Al–O glass and 63 for the Y–Si–Al–O–N glass. Mechanistic implications of these observations are discussed.     

Designing a computerized metrological production support system based on cals technologies

Designing a computerized metrological support system is considered, which incorporates not only metrological considerations on measuring instruments but also the computerized choice of production preparation facilities. Representations are considered for information on measuring instruments that allow one to integrate the metrological system in a unified CALS system for the organization. __________ Translated from Izmeritel’naya Tekhnika, No. 6, pp. 22–26, June, 2006.     

Corrosion and electrochemical properties of binary cobalt and nickel alloys

The influence of pH of electrolyte on the tungsten content and current efficiency of a Co–W coating is determined. We determine the corrosion rates of Co–W and Ni–Pd alloys by the polarization resistance method and show that the coatings are classified as belonging to highly corrosion-resistant coatings. The catalytic reactivity of coatings in a model reaction of hydrogen release is assessed. Dependences of the corrosion resistance and catalytic reactivity of Co–W and Ni–Pd alloys on the contents of the components are obtained, and their character is justified. Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 44, No. 6, pp. 89–92, November–December, 2008.     

Creep and fatigue behaviors of the lead-free Sn–Ag–Cu–Bi and Sn60Pb40 solder interconnections at elevated temperatures

Creep and fatigue behaviors of the interconnections soldered by the lead-free Sn–Ag–Cu–Bi solder were investigated at different elevated temperatures (with the homologue temperature in the range of 0.71– 0.82), with a comparison to that of a traditional Sn60Pb40 solder. The results show that the lead-free Sn–Ag–Cu–Bi solder shows a superior anti-creep performance over the Sn60Pb40 solder, in terms of a much lower creep strain rate and a vastly elongated creep fracture lifetime; in the secondary creep regime, the calculated creep-activation energy for two solders is reasonably close to other published data. In addition, it has also been shown that the joints soldered by the lead-free Sn–Ag–Cu–Bi solder exhibits a superb fatigue property.     

Phase Diagrams of Pb-Free Solders and their Related Materials Systems

Replacing Pb–Sn with Pb-free solders is one of the most important issues in the electronic industry. Melting, dissolution, solidification and interfacial reactions are encountered in the soldering processes. Phase diagrams contain equilibrium phase information and are important for the understanding and prediction of phase transformation and reactive phase formation at the solder joints. This study reviews the available phase diagrams of the promising Pb-free solders, and their related materials systems. The solders are Sn–Ag, Sn–Cu, Sn–Ag–Cu, Sn–Zn, Sn–Bi, Sn–In and Sn–Sb. The materials systems are the solders with the Ag, Au, Cu, Ni substrates, such as Sn–Ag–Au, Sn–Ag–Ni, Sn–Cu–Au, and Sn–Cu–Ni ternary systems. For the Pb-free solders and their related ternary and quaternary systems, preliminary phase equilibria information is available; however, complete and reliable phase diagrams over the entire compositional and temperature ranges of soldering interests are lacking.     

Influence of arsenic, antimony and phosphorous on the microstructure and corrosion behavior of brasses

The effect of minor additions of As, Sb and P on phase distribution and corrosion behavior has been studied in brasses. The alloys investigated were 60Cu–39Zn–1Pb, 48.95Cu–45Zn–5Pb–1Sn–0.05As, 48.90Cu–45Zn–5Pb–1Sn–0.05As–0.05Sb and 48.85Cu–45Zn–5Pb–1Sn–0.05As–0.05Sb–0.05P. Immersion tests in 1% CuCl₂ solution indicated that the addition of As improved corrosion resistance while the combined addition of As + Sb and As + Sb + P was not beneficial. The hardness increased significantly with the addition of As, Sb and P. Microstructural observations indicated an increase in β phase fraction in the As, Sb and P containing alloys. X-ray diffraction studies confirmed the formation of intermetallic compounds in As, Sb and P containing alloys. Based on the microstructural observations, the intermetallic compounds appear to be primarily precipitated in the β phase with As + Sb and As + Sb + P additions. The lower corrosion resistance of the alloys 48.90Cu–45Zn–5Pb–1Sn–0.05As–0.05Sb and 48.85Cu–45Zn–5Pb–1Sn–0.05As–0.05Sb–0.05P has been related to increase in β phase volume fraction and precipitation of intermetallic compounds in the β phase.     

The variation of beta phase morphology after creep and negative creep for duplex titanium alloys

The creep resistance of SP700 (Ti–4.5Al–3V–2Mo–2Fe) is superior to Ti–6–4 (Ti–6Al–4V) at 500 °C under a constant load corresponding to an initial stress of 100 MPa. The β phase grains in the SP700 alloy prefer to orient along the loading axis in contrast to the Ti–6–4 alloy. The grain growth occurs during the stress drop incubation period. The observation of different amounts of negative creep/anelasticity upon loading is closely associated with the difference in the amount of grain/subgrain coarsening.     

Dielectric and pyroelectric properties of a composite of ferroelectric ceramic and polyurethane

Flexible piezo- and pyroelectric composite was made in the thin film form by spin coating. Lead Zirconate Titanate (PZT) ceramic powder was dispersed in a castor oil-based polyurethane (PU) matrix, providing a composite with 0–3 connectivity. The dielectric data, measured over a wide range of frequency (10^–5 Hz to 10⁵ Hz), shows a loss peak around 100 Hz related with impurities in the polymer matrix. There is also an evidence of a peak in the range 10^–4 Hz, possibly originating from the glass transition temperature T_g of the polymer. The pyroelectric coefficient at 343 K is 7.0×10^–5 C·m^–2·K^–1 which is higher than that of β-PVDF (1×10^–5 C·m^–2·K^–1). Electronic Publication     

Development of antifriction aluminum-base alloys and compositions for sliding current collectors

We have studied the effect of alloying of aluminum with copper (2–4%), silicon (2–4.5%), tin (10–15%), and lead (10–15%) on its wear resistance under conditions of friction in a couple with a copper contact wire. We have established that alloying enhances the wear resistance of metals and decreases the wear of contact wires. The use of an electrographitic bush decreases the wear of a metal insert. Field investigations of metal trolleybus current-collecting inserts with electrographitic bushes show that their durability is 5–8 times greater in dry weather and 2–3 times greater in rainy weather than that of conventional articles. In addition, the wear of the contact wire is minimally admissible. __________ Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 42, No. 6, pp. 111–115, November–December, 2006.     

Properties of SnAgCu/SnAgCuCe soldered joints for electronic packaging

For quad flat packages (QFP256), lead-free soldered joints reliability in service is a critical issue. In this paper, soldering experiments of quad flat package (QFP256) devices were carried out by means of infrared reflow soldering system with Sn–3.8Ag–0.7Cu and Sn–3.8Ag–0.7Cu–0.03Ce lead-free solders, respectively, and the mechanical properties of micro-joints of the QFP devices were tested and studied by STR micro-joints tester. The results indicate that the tensile strength of Sn–Ag–Cu–Ce soldered joints is better than that of Sn–Ag–Cu soldered joints. In particular, the addition of trace Ce to the Sn–Ag–Cu solder can refine the microstructures and decrease the thickness of the intermetallic compound layer of Sn–Ag–Cu solder alloys. In addition, the stress–strain response of Sn–Ag–Cu/Sn–Ag–Cu–Ce soldered joints in quad flat packaging was investigated using finite element method based on Garofalo–Arrhenius model. The simulated results indicate creep distribution of soldered joints is not uniform, the heel and toe of soldered joints, the area between soldered joints and leads are the creep concentrated sites. The creep strain of Sn–Ag–Cu–Ce soldered joints is lower than that of Sn–Ag–Cu soldered joints.