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Metallic Materials (metallic + material)
Selected AbstractsEffect of Mounting Material Compliance on Nanoindentation Response of Metallic Materials,ADVANCED ENGINEERING MATERIALS, Issue 1-2 2009Grant A. Crawford Nanoindentation is an important and versatile technique for probing the properties of materials on the nanoscale. There are many factors that may affect nanoindentation measurements. One factor is the added compliance associated with mounting resins used to fix nanoindentation samples in place. We report on the effect of specimen mounting resin compliance on nanoindentation results. [source] The validation of some methods of notch fatigue analysisFATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 5 2000Taylor This paper is concerned with the testing and validation of certain methods of notch analysis which the authors have developed theoretically in earlier publications. These methods were developed for use with finite element (FE) analysis in order to predict the fatigue limits of components containing stress concentrations. In the present work we tested and compared these methods using data from standard notches taken from the literature, covering a range of notch geometries, loading types, R -ratios and materials: a total of 47 different data sets were analysed. The greatest predictive success was achieved with critical-distance methods known as the point, line and area methods: 94% of these predictions fell within 20% of the experimental fatigue limits. This was a significant improvement on previous methods of this kind, e.g. that of Klesnil and Lucas [(1980) Fatigue of Metallic Materials, Elsevier Science]. Methods based on the Smith and Miller [(1978) Int. J. Mech. Sci. 20, 201,206] concept of crack-like notches were successful in 42% of cases; they experienced difficulties dealing with very small notches, and could be improved by using an ElHaddad-type correction factor, giving 87% success. An approach known as ,crack modelling' allowed the Smith and Miller method to be used with non-standard stress concentrations, where notch geometry is ill defined; this modification, with the same short-crack correction, had 68% success. It was concluded that the critical-distance approach is more accurate and can be more easily used to analyse components of complex shape, however, the crack modelling approach is sometimes preferable because it can be used with less mesh refinement. [source] Microstructural and Mechanical Investigations on Porcelain-Fused-to-Metal in Multilayer SystemADVANCED ENGINEERING MATERIALS, Issue 4 2010Adele Carraḍ Results on porcelain-fused-to-metal (PFM) technique of ceramic films for biomedical applications on metal substrate are reported. The coating of metallic implants with bio-ceramic films (glassy and opaque ceramic) was proposed to be a solution for combining the mechanical properties of the metallic material with the bioactive character of the ceramic layer, leading to a better integration of the entire implant. The aim of this paper is to determine a stress field distribution by a non-destructive method as high-energy synchrotron X-ray diffraction in energy dispersive in the metal and glass ceramic bulk as well as at metal,opaque ceramic interface in PFM three layers sample. Tensile stresses were found in palladium substrate and compressive state in glass ceramic coating. Moreover thermal stresses induced by PFM coating at the interfaces were calculated by analytical mathematical model, confirming that the stresses induced, due to the selection of the materials, are low. Finally, the micro-structural and chemical characteristics of glassy and opaque bio-ceramic coatings on palladium alloy substrate were investigated and no inter-diffusion area between metal and ceramic could be detected as well as non-homogeneity in the interface ceramic. [source] A review of metal release in the food industryMATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 5 2006M. S. Jellesen Abstract The objective of this review is to outline literature on metal release in the food industry. Key results are reviewed from publications with high scientific level as well as papers with focus on industrial aspects. Examples of food products with a corrosive effect are given, and cases concerning processes, storing equipment as well as cleaning and sanitising procedures are reviewed. Stainless steel is the most widely used metallic material in the food industry; however other metals and their alloys are also briefly treated. The review deals with phenomena mainly relating to electrochemical corrosion, but also examples of material degradation as a consequence of wear and corrosive wear are presented. [source] Effect of mating surface on the high temperature wear of 253 MA alloyMATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 4 2004M. Roy Abstract The wear behaviour of metallic material is influenced by the friction force, which in turn, is governed by the hardness and oxidation kinetics of the mating surface. In view of this, present investigation is undertaken to find the influence of mating surface on the high temperature wear of 253 MA alloy. This alloy is developed for high temperature application. In this work 253 MA alloy is made to slide against two different types of counter face material, namely 100Cr6 steel and PM 1000 alloy, at five different temperatures. 100Cr6 steel gets soften with increase of temperature whereas PM 1000 alloy retains its strength even at high temperature. The friction coefficient and the thickness loss of 253 MA alloy is measured and compared against both variety of mating surfaces as function of temperatures. The morphology of the worn surfaces and the transverse section of the worn surfaces are examined under scanning electron microscope (SEM) to identify the material removal mechanisms. The results showed that the friction coefficient of test material against PM 1000 alloy is around 40% higher than the friction coefficient against 100Cr6 steel. The transverse section of the worn surface showed presence of a transfer layer, mechanically mixed layer and composite layer, which govern the wear behaviour particularly at elevated temperature. The chemical characteristics of these layers are dependent on the test temperature and the counter face material. [source] Materials Selection for Optimal Design of a Porous Radiant Burner for Environmentally Driven Requirements,ADVANCED ENGINEERING MATERIALS, Issue 12 2009Jaona Randrianalisoa Combustion supports which optimize a porous radiant burner are identified using a material selection approach. The optimization requirements account for the environmental aspect such as lower pollution. It was shown that high porosity metallic materials such as FeCrAlY foam, is always preferable in terms of pollution. From the viewpoint of thermal efficiency, metallic foams are better at high in-flux while Mullite foam takes over at low in-flux. [source] Specific aspects on crack advance during J -test method for structural materials at cryogenic temperaturesFATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 2 2006K. WEISS ABSTRACT Cryogenic elastic plastic, J -integral investigations on metallic materials often show negative crack extension values with respect to resistance curve J - R. According to the present ASTM standard, the use of unloading compliance technique relies on the estimation procedure of the crack lengths during the unloading sequences of the test. The current standard, however, does not give any specific procedure for treating such negative data. To date, the applied procedure uses the shifting of the negative crack extension values either to the onset of the blunting line or to the offset of the resistance curve. The present paper represents a solution of the negative crack length problem on the basis of a mechanical evaluation procedure of the unloading slopes. The achieved progress using this evaluation technique is demonstrated on different materials such as cryogenic high toughness stainless steels, low carbon ferritic steel and aluminum alloys from the series of 7000 and 5000. In addition, this work deals with the crack tunnelling phenomenon, observed for high toughness materials, and shows the reduction of this crack extension appearance by using electro discharge machining (EDM) side groove technique. The differences between EDM processed side grooves and standard V-notch machining have been investigated within these test series. [source] Experimental techniques for fracture instability toughness determination of unidirectional fibre metal laminatesFATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 11 2002E. M. CASTRODEZA ABSTRACT The aim of this work is to propose procedures for the measurement of the fracture toughness of fibre metal laminates (FMLs) reinforced with unidirectional fibres of aramid or glass. Experimental techniques for fracture toughness evaluation by using Compact (C(T)) and Single-Edge Bend (SE(B)) specimens obeying ASTM standards are introduced. Procedures from the standard for thick metallic materials were modified in order to overcome problems, which can arise when testing FMLs , that is, specimen buckling, indentations and crack growth in planes other than the plane of the fatigue pre-crack or notch. The methodology proposed was experimentally tested leading to satisfactory results. [source] A computerized procedure for long-life fatigue assessment under complex multiaxial loadingFATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 3 2001B. Li A computerized procedure is presented and evaluated for application examples of long-life fatigue analyses of metallic materials under complex multiaxial loading. The method is based on the stress invariants and uses the minimum circumscribed ellipse approach for evaluating the effective shear stress amplitude under complex multiaxial loading. The applicability of the procedure for handling non-proportional loading is examined through typical examples such as combined normal/shear stresses and combined bi-axial normal stresses with complex stress time histories. The effects of phase shift angles, frequency ratios and waveforms on fatigue endurance were re-analysed and compared with available experimental results from the literature. The comparison shows that the presented procedure based on stress invariants is a potential conservative engineering approach, very suitable for fast fatigue evaluation in the integrated computer aided fatigue design. [source] Arrays of Inorganic Nanodots and Nanowires Using Nanotemplates Based on Switchable Block Copolymer Supramolecular AssembliesADVANCED FUNCTIONAL MATERIALS, Issue 17 2009Bhanu Nandan Abstract Here, a novel and simple route to fabricate highly dense arrays of palladium nanodots and nanowires with sub-30,nm periodicity using nanoporous templates fabricated from supramolecular assemblies of a block copolymer, polystyrene- block -poly(4-vinylpyridine) (PS- b -P4VP) and a low molecular weight additive, 2-(4,-hydroxybenzeneazo) benzoic acid (HABA) is demonstrated. The palladium nanoparticles, which are directly deposited in the nanoporous templates from an aqueous solution, selectively migrate in the pores mainly due to their preferential attraction to the P4VP block covering the pore wall. The polymer template is then removed by oxygen plasma etching or pyrolysis in air resulting in palladium nanostructures whose large scale morphology mirrors that of the original template. The method adopted in this work is general and versatile so that it could easily be extended for patterning a variety of metallic materials into dot and wire arrays. [source] Intravascular bioresorbable polymeric stents: A potential alternative to current drug eluting metal stentsJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 11 2007Tahmer Sharkawi Abstract Stent implantation following angioplasty is the standard treatment of coronary artery disease necessitating interventional procedures. The use of stents as a platform for local drug delivery is a popular strategy to achieve local pharmacological treatment to the diseased artery. Drug eluting stents (DES) are now largely preferred to bare metal stents when stent implantation is necessary. Lately, there have been several reports questioning the long-term safety of DES. An alternative to these drug eluting metal stents are bioresorbable polymeric stents (BPS) because of the many advantages of bioresorbable material. However, the fundamental differences in polymeric and metallic materials make the development of such an alternative a significant challenge. This review discusses the different advantages of BPS and the many constrains and requirements of such devices. An up to date commented review of published data concerning BPS is presented. Considerations are given on using BPS as local drug delivery systems as well as on evaluating BPS performances. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 96: 2829,2837, 2007 [source] The fractal nature of elastic aftereffect in metallic materialsPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 3 2007V. Novikov Abstract Experimental investigations of the phenomenon of the elastic aftereffect of a number of metallic materials have been carried out. It was found that the time-dependent deformation may be described by a power function of time with fractional index. A mathematical model that describes the elastic aftereffect on a basis of fractal ideas about the process of deformation is constructed. A concept of a fractal set of relaxation periods is offered as an explanation of the elastic stability of the crystals, , or of their instability, i.e., emergence of residual deformation under the influence of external stress on the crystal system. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Local and non-local ductile damage and failure modelling at large deformation with applications to engineeringPROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2003Bob Svendsen Prof. Dr. The numerical analysis of ductile damage and failure in engineering materials is often based on the micromechanical model of Gurson [1]. Numerical studies in the context of the finite-element method demonstrate that, as with other such types of local damage models, the numerical simulation of the initiation and propagation of damage zones is strongly mesh-dependent and thus unreliable. The numerical problems concern the global load-displacement response as well as the onset, size and orientation of damage zones. From a mathematical point of view, this problem is caused by the loss of ellipticity of the set of partial di.erential equations determining the (rate of) deformation field. One possible way to overcome these problems with and shortcomings of the local modelling is the application of so-called non-local damage models. In particular, these are based on the introduction of a gradient type evolution equation of the damage variable regarding the spatial distribution of damage. In this work, we investigate the (material) stability behaviour of local Gurson-based damage modelling and a gradient-extension of this modelling at large deformation in order to be able to model the width and other physical aspects of the localization of the damage and failure process in metallic materials. [source] INVESTIGATION OF THE CONTENT OF ANCIENT TIBETAN METALLIC BUDDHA STATUES BY MEANS OF NEUTRON IMAGING METHODSARCHAEOMETRY, Issue 3 2010E. H. LEHMANN Many important cultural and religious objects from Asia consist of outer metallic shapes, usually bronze, which fully enclose inner contents made of organic materials such as wood, bark, paper, textile, plants and others. Bronze and other metallic materials, such as copper and silver, are generally more transparent to neutrons than to X-rays. However, organic materials are less transparent to neutrons than to X-rays and therefore organic materials, enclosed by metallic materials, can be made visible with neutrons. Therefore, neutron imaging (radiography and tomography) was found to be an ideal tool for the inspection of objects that consist of metal outside and organic materials inside. This has been successfully demonstrated here with four metallic Tibetan Buddha statues, providing archaeometry with a powerful new tool. The first successful applications of this novel technique are described in this article. Further possible and useful applications of neutron imaging of cultural objects are outlined. [source] | ||||||||||