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Search Results: 1 - 10 of 461998 matches for " A. Dolata-Grosz "
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Tribological properties of hybrid composites containing two carbide phases
A. Dolata-Grosz,J. Wieczorek
Archives of Materials Science and Engineering , 2007,
Abstract: Purpose: The article presents the research results on tribological properties (friction coefficient, wear) of the frictional couple cast iron-composite. The subject of that research was aluminium hybrid composites containing two carbide phases: chromium (Cr3C2) and titanium carbides (TiC).Design/methodology/approach: The friction process was conducted on a tribological pin-on-disc tester (T-01M) under technically dry friction conditions.Findings: The results of friction and wear coefficients’ investigation allowed the determination of how the volume fraction of NiCr/Cr3C2+TiC composite powder can influence on the course and degree of cast iron and composite wear.Practical implications: An increase in the reinforcing phase fraction allowed the elimination of the phenomena connected with adhesion wear. The 10% fraction of a carbide reinforcing phase ensures a uniform wear mechanism and has a beneficial influence on the operation of the tribological couple: cast iron – hybrid composite, during which no negative effects of increased wear of the cooperating material are observed.Originality/value: The application of heterophase reinforcement is a solution which to a large extent enables the broadening of the possibilities to design and diversify the tribological properties of friction couples.
Tribological properties of composite working under dry technically friction condition
A. Dolata-Grosz,J. Wieczorek
Journal of Achievements in Materials and Manufacturing Engineering , 2006,
Abstract: Purpose: The article presents the research results on tribological properties (friction coefficient, wear) of thefrictional couple cast iron-composite. The subject of that research was aluminium heterophase compositescontaining two carbide phases: chromium (Cr3C2) and titanium carbides (TiC).Design/methodology/approach: The friction process was conducted on a tribological pin-on-disc tester (T-01M) under technically dry friction conditions.Findings: The results of friction and wear coefficients’ investigation allowed the determination of how thevolume fraction of NiCr/Cr3C2+TiC composite powder can influence on the course and degree of cast iron andcomposite wear.Practical implications: An increase in the reinforcing phase fraction allowed the elimination of the phenomenaconnected with adhesion wear. The 10% fraction of a carbide reinforcing phase ensures a uniform wearmechanism and has a beneficial influence on the operation of the tribological couple: cast iron – heterophasecomposite, during which no negative effects of increased wear of the cooperating material are observed.Originality/value: The application of heterophase reinforcement is a solution which to a large extent enables thebroadening of the possibilities to design and diversify the tribological properties of friction couples.
Structure of Al-CF composites obtained by infiltration methods
A. Dolata-Grosz,M. Dyzia,J. ?leziona
Archives of Foundry Engineering , 2011,
Abstract: The structure of the composites obtained in infiltration processes 2D and 3D carbon preform by liquid Al alloy have been presented in thispaper. An aluminum alloy with silicon and manganese AlSi9Mn (trimal 37-TR37) was applied in the researches. As the reinforcementused carbon perform prepared with various protective barriers such as the nickel coating, the coating of silicon carbide and pyrolyticcarbon coating. Carbon preforms was prepared at the Institute for Lightweight Structures and Polymer Technology (ILK TU Dresden) andat the Institute of Technology and Ceramic Systems (Fraunhofer-IKTS). The process of infiltration of carbon perform by liquid aluminiumalloy was carried out using a pressure-vacuum infiltration on the Degussa press and gas-pressure infiltration (GPI) in an autoclavedesigned and built at the Department of Materials Technology at the Silesian University of Technology. The obtained composites werecharacterized by a regular shape, with no surface casting defects. The best connection of components was observed in AlSi9Mn/Cf(Ni)composite, obtained by gas-pressure infiltration method (GPI). On metallographic specimens, good interface between fibres and thealuminium matrix were observed. The obtained research results justify the application of nickel coatings on the fibres. During the failurecrack propagated across fiber. There was no presence of aluminum carbide on the fiber-matrix. It can be assumed that the composite willbe characterized by the good mechanical properties. However, this requires further experimental verification planned in the next stage of research, in the project realized within the DFG program: "3D textile reinforced aluminium matrix composites for complex loadingsituations in lightweight automobile and machine parts".
Die-cast heterophase composites with AlSi13Mg1CuNi matrix
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.
Solidification analysis of AMMCs with ceramic particles
A. Dolata-Grosz,M. Dyzia,J. Sleziona
Archives of Materials Science and Engineering , 2007,
Abstract: Purpose: In the research work the result of the reinforcement displacement and solidification analysis for aluminiumcast composites with ceramic particles have been presented. The results of research on the solidification procesare compared for the applied aluminium matrix alloy (AlSi12CuNiMg2), for composites containing glass carboparticles (Cg) and heterophase reinforcement (mixture of silicon carbide (SiC) + glass carbon particles (Cg)).Design/methodology/approach: The course of the solidification process was recorded by means of a systemwhich enabled continuous control and measurement of the metal temperature during solidification of the compositsuspension. The system was equipped with a thermoelectric cup core QC4080, with an incorporated thermocouple oK type (NiCr-Ni). The application of disposable thermoelectric cup cores of identical heat abstraction coefficient anknown, standardized dimensions, ensured identical conditions and rate of heat abstraction during the cooling of thcastings. The structure analysis for composite casts was performed by means of optical and scanning microscopy.Findings: The research has shown, that ceramic particles have an influence on temperature change and the timof aluminium matrix alloy solidification. The changes results, first of all, from disparate physical properties othe glassy carbon particles and silicon carbide particles used (thermal conductivity, mass density), compared taluminium matrix alloy.Practical implications: Ceramic particles decrease shrinkage of the casting and change the nature of itcrystallization.Originality/value: Employment of glass carbon particles for matrix reinforcement allows to get flotation in thaluminium alloy. Employment of heterophase reinforcement (glass carbon and silicon carbide particles) allows tget segregation of particles: flotation as well as sedimentation in the matrix, which results in the occurrence of layered structure.
Design, manufacture and technological verification of SiC/C composite stirrer
A. Dolata-Grosz,W. Hufenbach,J. ?leziona,M. Gude
Archives of Materials Science and Engineering , 2009,
Abstract: Purpose: In article were presented assumptions and choose results of investigations connected with material selection and technology production of prototype’s ceramic stirrer with destination to work in environment of liquid metal. In the research work the result of the design, manufacture and technological verification of SiC/C composite stirrer have been presented.Design/methodology/approach: The design of the stirrer (2D and 3D models) and strength tests on the blade and fragment of the composite axle was prepared in the programme Solid Works and the FEM, using COSMOS software. Polymer infiltration and pyrolysis (PIP) technique was used for fabrication SiC/C stirrer. Examination of wettability and suitability of the SiC/C composite for application in a liquid metal with sessile drop wettability was conducted. The surface geometry, conducted using a non-contact optical profilometer, FRT Micro’Prof.Findings: Further laboratory tests of the SiC/C composite stirrer, designed and developed in the Institute of Lightweight Engineering and Polymer Technology at TU Dresden have confirmed rightness of the design, assumptions regarding the thermal, mechanical and chemical resistance of the stirrer.Practical implications: The technological tests have proven a considerable reduction of the turbulence flow, which with an unchanged system of controlling the stirrer ensured stability of the liquid metal whirl and repeatability of the process.Originality/value: The application of this new material will enable not only the expansion of laboratory research, but it may also facilitate the implementation of liquid/phase technologies of obtaining MMC composites for the industry and thus, contribute to increasing the durability of stirrers in comparison with the solutions applied so far.
Structure and technological properties of AlSi12 –(SiCp + Cgp) composites
A. Dolata-Grosz,M. Dyzia,J. ?leziona
Archives of Foundry Engineering , 2008,
Abstract: In the article the structure and technological properties of aluminium cast composites with ceramic particles have been presented. Evaluation of casting properties of selected composite materials was made based on spiral tests. The differences occurring in solidification curves for materials reinforcing by silicon carbide, amorphous glass carbon particles and mixture of silicon carbide and glassy carbon particles were compared. On the basis of macro- and microstructural investigations of composite ingots after solidification at the same conditions the distribution of ceramic particles were estimated. The hardness on the cross section of formed composite ingots were presented in the graphic form.
The solidification process of the AK12/SiC+C composite suspension in various heat exchange conditions
A. Dolata-Grosz,M. Dyzia,J. ?leziona
Archives of Materials Science and Engineering , 2008,
Abstract: Purpose: In the research work the result of the structure and solidification analysis for aluminium cast compositewith ceramic particles in different solidification conditions have been presented. The results of research on thesolidification process for heterophase composite have been shown.Design/methodology/approach: The solidification process of the AK12/SiC+C composite suspension invarious heat abstraction conditions was recorded using the ThermaCAMTME25 photometer system for temperaturecontrol and measurement. The system, equipped with a thermovision camera, LCD display and a laser pointer, wasconnected to a SPIDER 8 recorder and used to monitor, record and, simultaneously, to visualize the temperaturechanges which take place during composites’ solidification. The structure analysis for composite casts wasperformed by means of optical microscopy.Findings: As the research has shown, moulds which abstract heat quickly, like a graphite or permanent mould, ensureobtaining a uniform distribution of ceramic particles in the matrix. A longer time of composite suspension solidificationfacilitates floatation and segregation of the reinforcing particles. Therefore, application of materials which prolong thesolidification process, e.g. a sand mould, enables obtaining a gradient or laminar structure in heterophase composites.Practical implications: The mould’s material changes the nature of composite crystallization.Originality/value: It was found that the has a significant influence on the distribution of heterophasereinforcement in the matrix. By applying an appropriate mould material it is possible to shape the cast structureand the distribution of particles in the cast.
Composites applied for pistons
Dolata-Grosz A.,Dyzia M.,?leziona J.,Wieczorek J.
Archives of Foundry Engineering , 2007,
Abstract: In the article the possibility of application the composite materials in casts into metal mould to form the pistons for compressors have been presented. In cooperation with “Zlotecki” company was undertaken the test of casting in productive conditions the aluminium alloy matrix composites reinforced with silicon carbide particles and composites reinforced with the mixture of the silicon carbide (SiC) and amorphous glass carbon particles. On the basis microstructural investigations were affirmed the uniformly distribution of reinforcing particles on the cross section of studied pistons. Realized technological tests confirmed the possibility of formation composite pistons with one kind of reinforcing phase and heterophase reinforcement from utilization the technology of mould casting.
Influence of modification on structure, fluidity and strength of 226D aluminium alloy
A. Dolata-Grosz,M. Dyzia,J. ?leziona
Archives of Foundry Engineering , 2008,
Abstract: In the article the fluidity, solidification conditions, microstructure and tensile properties have been studied for the non-modified and modified 226D aluminium silicon alloy.Realized investigations concerned modification of alloy 226D for application as the matrix to carbon fibre reinforcement composite (MMC-Cf). One of main factors determining to good connection between metal matrix and fibres reinforcement is good wettability. It is possible to obtain suitable conditions of wettability by modification of chemical composition metal matrix alloy or proper sizing of reinforcement fibres. Into consideration of interaction between liquide aluminium and carbon fibers following modifiers were used for addition to the commercial aluminium alloy (226D). The magnesium (2%Mg), strontium (0,03%Sr) and titanium (0,5%Ti) with boron (0,01%B) modifiers and their combination were used in the presented work.
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