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Search Results: 1 - 10 of 297535 matches for " J. ?leziona "
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Silver matrix composites reinforced with galvanically silvered particles
J. Wieczorek,,J. ?leziona
Archives of Materials Science and Engineering , 2007,
Abstract: Purpose: The paper presents the possibility of the application of metalic layers drifted with the use of the galvanic methods on the ceramic particles surface. The application of the layers was aimed at obtaining the rewetting of the reinforcing particles with the liquid silver in the course of the producing of silver matrix composites with the use of mechanical stirring method. To enable introducing of the iron powder and glass carbon powder to liquid silver the solution of covering the powder layer with the silver or copper coats was proposed.Design/methodology/approach: For silver coating the method of non-current deposition from the solution was used.Findings: Conducted investigations allowed such a selection of non-current coating parameters that durable and qualitatively satisfactory coats on the iron particles surface could be obtained.Research limitations/implications: In the course of the researches it was stated that the temperature of the bath, the time of the spread and the intensity of the stirring were the most important parameters of the deposition method itself that guaranteed the obtaining of the coat. The conducted investigations allow to state that the most favourably from the quality of the obtained composite point of view were the applications of the silver coat on the surface of the iron particles and copper coat for glass carbon covering.Originality/value: Selection of the deposited galvanic coats allows to obtain the good quality of the connection on the reinforcing particle sliver matrix interface.
Tribological properties of silver matrix composites
J. Wieczorek,J. ?leziona
Archives of Foundry Engineering , 2007,
Abstract: Silver, silver alloys, as well as matrix based composites have been well known and applied in the electrotechnical and electronics industry for several decades. For many applications in electrotechnology, including electric contacts and brushes, unreinforced sliver alloys do not meet the requirements concerning mainly durability and wear resistance, first of all to tribological and electroerosive wear. These wear processes may be prevented by introducing to silver reinforcement particles. It can be stated, comparing recorded friction coefficient values of all investigated materials, that in the dry sliding conditions the ceramic particles introduction into matrix has its effect on the friction coefficient value lowering. If metallic particles are used as reinforcement, and in the investigated composites iron particles were used, the friction coefficient increases its value comparing to the matrix.
Characteristic of polymer sliding materials using to work at elevated temperature
J. Myalski,J. ?leziona
Archives of Materials Science and Engineering , 2008,
Abstract: Purpose: The purpose of this project was to estimate the possibility of using glass carbon particleste as areinforced component of polymer matrix in composites. Application as a basic components modified properties ofphenolic resin glass carbon give a sliding composites characterized profitable tribological properties. Microscopyexamination of the sliding surface together with the results of tribological investigations made it possible toconclude about friction and wear processes of the investigated composites.Design/methodology/approach: Composites on the phenolic resin as a matrix have been investigated. Apartfrom traditional fillers, such as graphite or brass, glassy carbon was used for the modification of the properties.Based on studies of the friction coefficient and the wear, usefulness of glassy carbon as a material reinforcingand modifying the tribological properties of sliding materials was determined. Studies of the surface structures offriction couple materials allowed the identification of the processes taking place in the upper surface after frictionand wear tests, as well as the determination of wear mechanisms. Analysis of composite surface after friction giveestimation of wear mechanism and forming of surface layer during friction.Findings: The results of research into mechanical and tribological properties of materials with a polymer matrixintended for work in friction couples under heavy load conditions.Practical implications: The results of that investigation confirm that glass carbon is main component decidingon the tribological properties of composites. Glassy carbon particles limited wear and thermal destruction ofmatrix. Modification using glassy carbon let to obtain sliding composites working at elevated temperature inextremely work condition then non modified polymer materials.Originality/value: Glassy carbon particles limited wear and thermal destruction of matrix. Modification usingglassy carbon let to obtain sliding composites working at elevated temperature in extremely work condition thennon modified polymer materials.
Influence of preparing of GFR recyclates on the properties of polyester matrix compsites
J. Myalski,J. ?leziona
Journal of Achievements in Materials and Manufacturing Engineering , 2006,
Abstract: Purpose: The purpose of this project was to estimate the possibility of using polyester-glass fiber recyclate as areinforced component of polymer matrix in composites. This kind of mechanical recycling can be use as one of theway of polymer composites utilization. Recyclates prepared from GFP - polyester resin reinforced glass filaments.Design/methodology/approach: Recyclate obtained after grinding was a mixture of cured polyester resin particlesand glass fibers. Two different groups of recyclates have been obtaining after separation. First group of recyclatewas used to prepare of stratified laminates. Second group of recyclate was used as a filler of polymer matrix.Findings: The results of the investigation have shown that using of polymer composites wastes as a filler, leadsto decreasing of the flexural and impact strength. However obtained material had a bending strength comparablewith standard material. The results of mechanical properties have been prove that change of propertiesdepends on the size of fraction recyclate. Fraction containing the particles in fibrous shape better influenceon that mechanical properties of laminates. The results of the investigation have shown that using of polymercomposites wastes as a filler materials (core), leads to decreasing of the properties in bending and impact tests.It has been shown that content of the recyclate has significant influence on studied mechanical properties.Practical implications: The results of the investigation have shown that using of polymer composites wastesas a filler, leads to decreasing of the properties in bending and impact tests. Surface treatment of recyclates hasbeen shown that bending strength between matrix and recyclates improve.Originality/value: The results of the investigations allow to confirm, that the polymer composites waste canbe used as a filler polymer matrix in production of new composites, being also one of the way of utilization ofcomposite with thermosetting matrix.
Effect of modification on the mechanical properties of IN-713C alloy
F. Binczyk,J. ?leziona
Archives of Foundry Engineering , 2010,
Abstract: The results of studies on the effect of modification on macrostructure and mechanical properties (hardness, R02, Rm, elongation A5 and reduction of area Z) of IN-713C nickel alloy, examined on “carrot”- type specimens(1) were presented. One surface-volume modified melt and two volume-modified melts were made. As a reference, the results obtained on non-modified castings were used. A very beneficial effect of the combined surface-volume modification on alloy macrostructure (equiaxial crystals) and mechanical properties was reported. Volume modification produces mixed structure of columnar and equiaxial crystals. The efficiency of modification was additionally enhanced by application of filters made according to the authors’ genuine design. The inoculant used in these filters was cobalt aluminate CoAl2O4 .
Mechanical properties and creep resistance behaviour of IN-713C alloy castings
F. Binczyk,J. ?leziona
Archives of Foundry Engineering , 2010,
Abstract: The paper presents the results of investigations on the effect of modification process on mechanical properties and high-temperature creep resistance behaviour of IN-713C alloy specimens. Two melts modified in volume were made and one melt modified by combined surfacevolume technique. A beneficial modifying effect of filters designed according to the authors’ genuine concept has been proved. As a reference, the results obtained on non-modified castings were used. A very beneficial effect of combined modification on the degree of equiaxial grain refinement and increase of Rm and R02 has been reported. Unfortunately, refining of macrostructure obviously deteriorates the alloy high-temperature creep resistance behaviour.
The ATD thermal analysis of selected nickel superalloys
F. Binczyk,J. ?leziona
Archives of Foundry Engineering , 2010,
Abstract: The study presents the results of the ATD thermal analysis made on selected nickel alloys used by WSK Rzeszów for parts of aircraft engines. The aim of the studies was investigation of solidification parameters, especially Tlik and Tsol. The said parameters are very important in the determination of pouring temperature and maximum operating temperature of castings. Another important technical information is the quality of “master heat” ingots, examined for the stability of chemical composition and presence of different impurities. It has been concluded that the pouring temperature of CMSX-4 and MAR-247 alloys should be comprised in a range from 1470 to 1480°C, while for the remaining alloys the recommended range of pouring temperatures is from 1440 to 1450°C. Examinations have also proved that some batches of the supplied ingots are contaminated with non-metallic impurities, located mainly in the region of shrinkage cavities.
Aluminium matrix composites reinforced with AlN particles formed by in situ reaction
M. Dyzia,J. ?leziona
Archives of Materials Science and Engineering , 2008,
Abstract: Purpose: Ultrafine reinforcement particles are formed as product of reaction between reactive components. Thosekinds of materials have good mechanical properties (higher yield stress and creep resistance). Via in situ reactionbetween liquid metal and reacting substance (solid or gas) is possible to obtain aluminium matrix composites similarto SAP composites by casting methods. Presented results of researches concerning possibilities of obtaining ultrafinealuminium nitride particles via in situ reaction between aluminium alloys (with addition of Mg) and nitrogen.Design/methodology/approach: The experiments were performed in a reaction chamber, heated in a sylitefurnace where the 0.3 MPa pressure of nitrogene were obtained and autoclave furnace at gas pressure of 1 MPa.Samples were heated at 1000°C and held at that temperature for 1 hour at the suitable gas pressure.Findings: The research has shown, that vaporization of Mg and indirect nitridation depend on gas pressure inreaction chamber. At high pressure (1 MPa) of N2 in situ reaction procced in limited scope.Practical implications: Using the in situ reaction in order to form AlN dispersion reinforcement in thealuminium alloy matrix seems possible but the control of the reaction is difficult.Originality/value: During the liquid-phase process, the following factors determine the possibility of controllingthe process of the dispersion reinforcement phases’ formation: the matrix alloy composition, the temperature, thereactive gas pressure and the time of synthesis.
Macro- and microhardness of IN-713C nickel superalloy constituents
F. Binczyk,J. ?leziona
Archives of Foundry Engineering , 2009,
Abstract: The results of investigations of the effect of modification and cooling rate on the macrohardness of castings and microhardness of phase constituents in IN-713C nickel superalloy were described. As an inoculant, cobalt aluminate CoAl2O4 in composition with aluminium powder and colloidal silica was used. Changes in the cooling rate were obtained using a cast stepped test piece with steps of 6, 11 and 17 mm thickness. Macrohardness of the cast test piece steps was measured by Brinell technique, while Vickers method was used to measure the microhardness of γ and γ’ phases present in the alloy matrix, as well as the hardness of eutectic carbide precipitates.A significant effect of the cooling rate and modification treatment on the results of the measurements was stated, and difficulties in performing correctly the microhardness measurements due to the precipitates dimensions, especially after the modification treatment, were highlighted.
Determining the applicability of liquid alloy nitriding in fabrication of Al-AlN particle composites
J. ?leziona,M. Dyzia
Archives of Foundry Engineering , 2008,
Abstract: One of the possible techniques of the fabrication of dispersion-hardened composites is by in situ reaction between the liquid alloy and gas. The study presents the results of the research on nitriding of liquid aluminium alloy containing Mg and Ti as alloying elements under the conditions of high pressure comprised in the range of 150-1000hPa at the temperature of up to 1100oC. It has been stated that under the applied conditions of the synthesis it is possible to obtain the AlN nitride, but it is formed on the liquid alloy surface and as a deposit on the surface of the crucible. Some results of the analysis of the phase constitution obtained in the fabricated products were presented along with the structure of these products.
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