2. Ερευνητικές - Επιστημονικές Δημοσιεύσεις του Ακαδημαϊκού Προσωπικού
Μόνιμο URI για αυτήν την κοινότηταhttps://repository2024.ihu.gr/handle/123456789/30486
Περιηγούμαι
Πλοήγηση 2. Ερευνητικές - Επιστημονικές Δημοσιεύσεις του Ακαδημαϊκού Προσωπικού ανά Συγγραφέα "Agrianidis, P."
Τώρα δείχνει 1 - 6 από 6
- Αποτελέσματα ανά σελίδα
- Επιλογές ταξινόμησης
Τεκμήριο Characterization of Al Metal Matrix Composites Produced by the Stir-Casting Method(2013-09) Anthymidis, K. G.; David, K.; Trakali, A.; Agrianidis, P.Composite materials which main constituent part is a metal are called Metal Matrix Composites (MMCs). The other compounds may be metals too, ceramics or even organics. They are well known for their excellent thermo-physical and mechanical properties. Reinforcement is used to improve different properties of the main material, such as wear resistance, hardness, fatigue resistance, friction coefficient, thermal conductivity and others. As a result, during the last years, MMCs have found a lot of application in automobile industry for the production of brakes and parts of engines and in aerospace industry for the production of structural components, as well as in electrical and electronic industry and in many other applications. MMCs can be produced by many ways, such as, powder blending and consolidation, foil diffusion bonding, electroplating, spray deposition, stir-casting and others. In this research stir-casting was used as processing technique for the production of Aluminum matrix composites reinforced by ceramic particles and iron. The morphologies of the produced composite materials were examined using optical and SEM microscopy. The compositions of their micro structural features were determined by EDX spectroscopy. The phases formed were determined by XRD techniques. In the tribological tests, under dry wear conditions, the as-produced composites materials showed significant increased resistance to wear compared to pure Al metal.Τεκμήριο Deposition of coatings containing Si and B on steels in a CVD fluidised bed reactor(2005-01) Agrianidis, P.; Anthymidis, K. G.; David, K.; Tsipas, D. N.Diffusion coatings are frequently used to protect materials in various aggressive environments and in order to improve their surface properties. Fluidized bed technology (FBT) has been successfully used for the deposition of different types of diffusion coatings by a C.V.D. process, e.g. aluminizing, chromizing, nitriding, carburizing. On the other hand, very little information exists on boronizing or siliconizing using FBT, although the method is simple, efficient and environmentally friendly and the boride coatings have been reported to have an excellent combination of properties, e.g. high fatigue strength and wear resistance and the silicide coatings are well known for their excellent corrosion resistance. In this paper the results of a process of boronizing and siliconizing of steels via C.V.D. in a fluidised bed reactor are presented. Coatings of different thicknesses were obtained at temperatures below 1000°C. The coatings were analysed by means of optical microscopy, as well as by x-ray diffraction (XRD) and Vickers microhardness, in terms of the coating’s composition, morphology, thickness, hardness and phase formation. The boride coatings showed significantly improved tribological properties under dry wear conditions.Τεκμήριο Determination of the Fatigue Behavior of Aluminide Coatings by Means of the Impact Testing Method(2007-09) David, K.; Anthymidis, K. G.; Agrianidis, P.; Tsipas, D.N.The impact testing is an efficient experimental method that enables the quantitative and qualitative determination of the fatigue resistance of mono- and multilayer coatings deposited on various substrates, which was not possible with the common testing methods previously available. In this paper the experimental assessment of the fatigue resistance of coatings working under cyclic loading conditions by means of the dynamic impact testing method is presented. The fatigue failure mode, such cohesive or adhesive, of the investigated coatings is determined using scanning electron and optical microscopy, as well as EDX analysis. Critical values of the stress components, responsible for distinctive fatigue failure modes of the coating substrate system are obtained and the fatigue limits of aluminide coatings are illustrated in simple diagrams containing the impact load versus the number of successive impacts that the examined aluminide-P91 system can withstand.Τεκμήριο Interregional technology transfer on advanced materials and renewable energy systems(2008) Agrianidis, P.; David, C.; Anthymidis, K.; Ekhrawat, M.Advanced materials are used in most industrial sectors and human activities and all developing and developed countries as well as international organizations eg. United Nations have established work groups, which survey the national and global state and developments in the area of advanced materials trying to establish strategies on that crucial technology sector. These strategies are focused on research and technology activities including education and vocation training, as well as stimulus for the starting up of new industrial applications. To introduce such a concept in Greece and especially in Northern Greece, the Technological Education Institute of Serres has initiated an Interregional technology transfer project in this scientific field. This project includes mod topics of advanced materials technology with emphasison specific industrial applications (renewable energy systems). The project demonstrates the development of a prototype photovoltaic thermal system in terms of a new industrial product. The product development procedure consists of steps such as initial product design, materials selection and processing, prototype design and manufacturing, quality control, performance optimization, but also control of materials ecocompatibility according to the national trends of life cycle design and recycling techniques. Keywords: Interregional technology transfer, materials, renewable energy systemsΤεκμήριο Mechanical properties of aluminum metal matrix composites(2009-10) Agrianidis, P.; Agrianidis, T.; Anthymidis, K. G.; Trakali, A.Aluminum matrix composites reinforced by ceramic particles are well know for their good thermo-physical and mechanical properties. As a result, during the last years, there has been a considerable interest in using aluminum metal matrix composites (MMCs) in the automobile industry. These potential applications have greatly stimulated the tribological studies of MMCs under different operating conditions. In this paper, TiB – particles - reinforced aluminum - tungsten matrix composites were fabricated by the cost – effective squeeze – casting technology and their microstructure characteristics and mechanical properties were investigated. The microstructure observation showed that the produced composites were dense, with no micro-holes and obvious defects. Their wear resistance was evaluated using a pin on disc type equipment under dry wear conditions and found significantly increased compared to pure Al metal.Τεκμήριο Reinforcement of aluminum by TiB dissolution(2008-07) Agrianidis, P.; Anthymidis, K. G.; David, K.Interactions between solid materials and liquid aluminum lead to a dissolution of solid elements into aluminum, which in turn results in a subsequent growth of intermetallic and intermediate phases. It was established that the growth of the intermetallic phases could be governed by chemical reactions at the interfaces and by interdiffusion of the reacting elements through the different phases. Dissolution on the other hand mainly depends on thermodynamic conditions, experimental parameters such as temperature, stirring time, and reacting holding time and on the degree of the saturation of aluminum as well as on the chemical composition of the solid materials in the reaction zone. The above-mentioned factors play also an important role in the formation of the different phases during dissolution. Nevertheless, a non-uniform distribution of the solute elements may causes a local concentration of these elements into the liquid aluminum, which practically delays the process or alters the equilibrium of the growth of the phases. Thus it is crucial to control the dissolution conditions so that the instabilities induced at the solid materials/aluminum interface are limited. The main objective of this study was to investigate both the formation of intermetallic and intermediate phases in the reaction zone and to examine the development of the diffusion structures of pure aluminum reinforced with TiB particles and to investigate the mechanical properties of the as-produced composite materials.