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Technological aspects of AlSi-CrxCy composite casting manufacturing with use of permanent moulds  [PDF]
M. Cholewa,M. Kondracki,M. Stawarz
Archives of Foundry Engineering , 2008,
Abstract: In this work authors presented the restrictions and possibilities of permanent mould casting technique in manufacturing dispersive composite elements reinforced with metallic particles. The characteristic feature of such particles is their physical and chemical reactivity, which deteriorates the rheological properties of the liquid dispersion. Selection of technological parameters for manufacturing and casting is aimed on proper filling of the mould with liquid dispersion. For comparison, the results of similar experiments with use of investment casting were shown. Basic constructional requirements connected with brake discs manufacturing were presented, together with the concept of moulding materials selection, influencing the flow of liquid dispersion. As the results of conducted studies technological parameters of brake disc manufacturing with use of AlSi-CrxCy composites were determined.
Continuous drive friction welding of cast AlSi/SiC(p) metal matrix composites  [PDF]
Wysocki J.,Grabian J.,Przetakiewicz W.
Archives of Foundry Engineering , 2007,
Abstract: Continuous drive friction welding of cast AlSi/SiC(p) metal matrix composites in systems AlSi11-AlSi9/SiC/21(p), AlSi9/SiC/21(p)-AlSi9/SiC/21(p) AlSi11/SiC/15(p)-AlSi11/SiC/15(p) have been made. Examination of welds microstructure revealed that during friction welding process three different zones of size and distribution reinforced particles in the metal matrix appeared. Discernible effect of friction welding parameters on the microstructure matrix has been noticed. Subsequent hardness tests confirmed changes in matrix microstructure and influence particles redistribution on the weld mechanical properties.
Weld microstructure in cast AlSi9/SiC(p) metal matrix composites  [PDF]
J. Wysocki,K. Gawdzinska,S. Lenart
Archives of Foundry Engineering , 2009,
Abstract: Welded joint in cast AlSi9/SiC/20(p) metal matrix composite by manual TIG arc welding using AlMg5 filler metal has been described inhis paper. Cooling curves have been stated, and the influence in distribution of reinforced particles on crystallization and weldmicrostructure. Welded joint mechanical properties have been determined: hardness and tensile.
The Influence of the Forced Movement of Components on the Structure in Fabricated AlSi/CrxCy Composite Castings
A. Dul ba , M. Cholewa , D. Scelina
Archives of Foundry Engineering , 2012, DOI: 10.2478/v10266-012-0005-1
Abstract: Fabrication and microstructure of the AlSi11 matrix composite containing 10 % volume fraction of CrFe30C8 particles were presented in this paper. Composite suspension was manufactured by using mechanical stirring. During stirring process the temperature of liquid metal, time of mixing and rotational speed of mixer were fixed. After stirring process composite suspension was gravity cast into shell mould. The composites were cast, applying simultaneously an electromagnetic field. The aim of the present study was to determine the effect of changes in the frequency of the current power inductor on the morphology of the reinforcing phase in the aluminum matrix. The concept is based on the assumption that a chromium-iron matrix of CrFe30C8 particles dissolves and residual carbide phases will substantially strengthen the composite. The microstructure and interface structure of the AlSi11/CrFe30C8 composite has been studied by optical microscopy, scanning microscopy and X-ray diffraction.
The influence of the forced movement of components on the structure in fabricated AlSi/CrxCy composite castings  [PDF]
A. Dul?ba,M. Cholewa,D. Scelina
Archives of Foundry Engineering , 2012,
Abstract: Fabrication and microstructure of the AlSi11 matrix composite containing 10 % volume fraction of CrFe30C8 particles were presented in this paper. Composite suspension was manufactured by using mechanical stirring. During stirring process the temperature of liquid metal, time of mixing and rotational speed of mixer were fixed. After stirring process composite suspension was gravity cast into shell mould. The composites were cast, applying simultaneously an electromagnetic field. The aim of the present study was to determine the effect of changes in the frequency of the current power inductor on the morphology of the reinforcing phase in the aluminum matrix. The concept is based on the assumption that a chromium-iron matrix of CrFe30C8 particles dissolves and residual carbide phases will substantially strengthen the composite. The microstructure and interface structure of the AlSi11/CrFe30C8 composite has been studied by optical microscopy, scanning microscopy and X-ray diffraction.
Heat flow description during crystallization process of cast dispersive composites  [PDF]
Cholewa M.
Archives of Foundry Engineering , 2007,
Abstract: The aim of this work was to show possibilities of numerical simulation software, based on heat transfer model, commonly used in foundry industry in cast composite properties engineering. The main restriction in most of used software systems is lack of heat transfer, which may occur at composite creation. In this work the reinforcing particle morphology an size were expressed by one quantity – morphological modulus Mm and were examined for influence on heat transfer and conductivity up to the Newton’s and Fourier’s laws. The main restrictions for using Fourier’s model based software for composite engineering are shown. The way for crystallization control was presented including influence of morphology, transition zone and thermo-physical properties of components. Proposed methodology can be used for cast composite properties engineering in cases, where relative motion of components is negligible. In other cases heat transfer coefficient is justified only if the software used is based on Fourier’s model and the source code is accessible. Proposed assumptions create possibility for components selection verification in terms of technological and operating properties of cast composite. An example of such approach was shown in work [1, 23].
Die-cast heterophase composites with AlSi13Mg1CuNi matrix  [PDF]
M. Dyzia,A. Dolata-Grosz,J. Wieczorek,J. ?leziona
Archives of Foundry Engineering , 2010,
Abstract: On the basis of the performed tests, an advantageous interaction of glassy carbon particles in a couple consisting of a heterophase composite and a spheroidal cast iron has been corroborated. It was found that, the presence of glassy carbon in the heterophase composite (SiC+C) affects the stabilization of the friction coefficient value as a function of the friction distance and reduces the intensity of the wearing-in stage of the interacting surfaces. Both a decrease of the friction coefficient and the wear of the heterophase composites may be connected with the carbon particles' chipping effect and the deposition of its fragments on the surface of the interacting components of the friction couple, which forms a kind of a solid lubricating agent in the system. This should allow applying of this material to the composite piston - cylinder sleeve system in piston air-compressors. Further works will concern the selection of the matrix alloy composition with the purpose of reducing the phenomenon of particles chipping during machining. It seems that one of the possibilities is the application of a more plastic matrix and optimizing the fraction of reinforcing phases and their gradient distribution in the casting.
Corrosion behaviour of the AlSi6Cu4 alloy and cast AlSi6Cu4-graphite particles composite  [PDF]
Z. Konopka,S. Holecek,J. Pozar,M. Nadolski
Archives of Foundry Engineering , 2009,
Abstract: The corrosion behaviour of the AlSi6Cu4 alloy as a composite matrix and of composites with 8% vol. of graphite particles was investigated. The corrosion experiments were performed over a range of elevated temperatures and were carried out in sea water (3.5%NaCl solution). We have focused our attention to the determination of the mode of corrosion attack and to the determination of the rate ofcorrosion and other corrosion characteristics. Both as-cast and annealed matrix and composite specimens were tested, as well as the99.9% as-cast aluminium for comparison. Corrosion behaviour of the materials was assessed by the corrosion potential (Ec) and bypotentiodynamic (polarization) curves. As expected, composite is less corrosion resistant than the matrix alloy. In addition to pitting,a severe galvanic corrosion occurs as a result of galvanic couple aluminium/graphite formation. Corrosion potentials imply that examinedmaterials would be sufficiently resistant in non or slightly oxidizing solutions without dissolved oxygen. All studied materials corrode very slowly at potentials negative to corrosion potential, while at potentials positive to corrosion potential the corrosion rate goes up by 1 or 2 orders.
Al - BASED CAST COMPOSITES  [PDF]
Rakesh Kumar Yadav,Ashu Yadav
International Journal of Computer Science and Management Studies , 2011,
Abstract: The economy is very important feature nowadays in themarket. The researches are playing an important role inengineering field to increase the life of machine parts /components and decrease the cost. The compositematerials have the potential to replace widely used steeland aluminium due to their good characteristics withbetter performance. The Al-based composites have foundextensive applications in automobile industries andaerospace industries due to their increased stiffness,strength, thermal conductivity and wear resistanceproperties. A number of particulate phases have beenemployed in the Al-alloy matrix. The cast aluminiumceramicparticulate composites are finding applications inpistons, connecting rods, cylinder liner, engine cylinderblock, electrical contacts etc.The present investigation isbased on study of the effect of particulate phase on theSEM study, micro-hardness, elastic modulus, tensilestrength and the wear behaviour of Al-5 % SiC-7 % Fe,Al-10 % SiC-6 % Fe and Al-15 % SiC-5 % Fe composites.
Laser cutting of an AlSi alloy/SiCp composites: theory and experiments  [PDF]
A. Grabowski,M. Nowak,J. ?leziona
Journal of Achievements in Materials and Manufacturing Engineering , 2006,
Abstract: Purpose: Discontinuous silicon carbide reinforced aluminium alloy metal matrix composites have proved to be extremely to cutting using conventional cutting tools. Thus, there is a need to introduce new processing method in order to improve both the working conditions and the quality of the products made of metal matrix composites. Laser processing offer the advantages of high processing rates, no tool wear, no contact forces, and relatively high precision. Currently the mechanisms governing the laser cutting process of composites are not fully understood. It is the aim of the authors therefore to investigate the physical processes of laser composite material interactions and the phenomena occurring within the cutting front, viz. the formation of striations, and the effect they have on the resulting cutting quality.Design/methodology/approach: The analysis has taken into the consideration these AlSi alloy/SiCp composites are heterogeneous structural material consisting of two components: a semiconductor and metal alloy that have two different optical absorptions mechanisms to laser radiation. The mathematical model based on energy and mass balance model was used to calculate the maximum cutting depth for fixed cutting speed and laser beam power.Findings: Results indicated that the change in absorptivity magnitude about 0.1 led to a strong increase in power of laser energy absorbed per unit depth in AlSi alloy/SiCp composites.Research limitations/implications: In mathematical modeling the constant values of the effective absorptive parameter describing the energy input from laser to composite and a constant thermophysical properties of composite components are used. During the laser beam scanning the absorptive of the composite surface may changes.Practical implications: The proposed mathematical model is in good agreement with the experimental data obtained for a CO2 laser cut of AlSi alloy/SiCp composites. It is important to understand the characteristics of the striation so that the laser cutting process of composite can be optimized.Originality/value: The cut kerf characteristics such as the dross formation, the heat affected zone in terms of laser parameters process was investigated.
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