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    Designing of a powder compressing device with vibration and investigation of compressibility of MgO powders with this device
    (Elsevier Sci Ltd, 2007) Çalin, Recep; Citak, Ramazan
    One of metal matrix composite (MMC) production methods is infiltration of liquid metal into preformed reinforcement. In this method, MMCs are produced by infiltration of liquid metal into preformed reinforcement using one of pressure, vacuum or pressureless (free) infiltration methods. For infiltration purposes, reinforcement materials in different figuration are preformed in desired shape and reinforcement volume ratio. In this study a vibration apparatus has been designed to compress the particulate reinforcement in a tube so that pressure or vacuum infiltration can be carried out. The compressibility of MgO powders with different sizes with this apparatus has also been investigated. It has been found that with this apparatus, it is possible to compress desired number of specimens uniformly at the same time and at the same ratio. It has also been determined that MgO powders can be compressed in different ratio due to particle sizes with this device. Compressing time of 3 min is enough to reach maximum compression ratio in MgO powders. (c) 2006 Elsevier Ltd. All rights reserved.
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    Effect of Infiltration Pressure on Thermal Conductivity of Al 2014 Matrix Composite Powered by Silicon Carbide
    (Asian Journal Of Chemistry, 2012) Ates, Serkan; Uzun, Ibrahim; Çalın, Recep; Citak, Ramazan
    By using pressure infiltration method, metal matrix composites are produced by saturating Al 2014 aluminum composite to the gaps among SiC powders. SiC powders filled into stainless steel tubes are fastened between the filters conducting only liquid material, dipped into pressurized molten boiler and infiltrated in 3 min under 500-900 kPa pressures at 750 degrees C. The image analyses of samples were done by scanning electron microscope (SEM). Densities, porosities and thermal conductivities of them were identified experimentally. It is defined that by the increase of infiltration pressure, porosity amount decreases but the value of thermal conductivity increases.
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    Effect of matrix temperature and powder size on the infiltration height of SiO2 -reinforced Al 7075 matrix composites produced by vacuum infiltration
    (Adcotec Ltd, 2011) Calin, Recep; Pul, Muharrem; Citak, Ramazan; Seker, Ulvi
    In this study, Al-MgO metal matrix composites (MMC) were produced with 5 %, 10 % and 15 % reinforcement-volume (R-V) ratios by the melt stirring method. In the production of composites 99.5 % pure Al was used as the matrix and MgO powders with the particle size of -105 mu m were used as the reinforcement. For every R-V ratio; stirring was made at 500 rev/min at 750 degrees C liquid matrix temperature for 4 minutes and the samples were cooled under norrnal atmosphere. Then hardness and fracture strengths of the samples were determined and their microstructures were evaluated by using Scanning Electron Microscope (SEM). In general, it was observed that the reinforcement exhibited a homogeneous distribution in horizontal direction. But there is a slight inhomogeneity in vertical direction. It was determined that the increase in the R-V ratio increased the porosity and also the hardness. As for the fracture strength, the highest strength was obtained with the 5 % MgO reinforced sample.
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    Effect of powder size on infiltration height in producing MgO reinforced Al matrix composite by vacuum infiltration method
    (Trans Tech Publications Ltd, 2007) Çalın, Recep; Citak, Ramazan
    The vacuum infiltration method is one of the composite producing methods. There are several parameters in composite production by vacuum infiltration. One of them is particle size of reinforcement in particulate reinforced composites. In this study, MgO powder and Al were used as reinforcement and matrix respectively. MgO powders with different size and amount to give same height were filled in quartz tubes and liquid metal was vacuum infiltrated into the MgO powder under same vacuum condition and for same time. Infiltration height was measured and microstructure and fracture behavior of composite were investigated. It has been found that infiltration height and fracture strength were increased with particulate reinforcement sizes. It has also been determined that molten metal temperature facilitates infiltration.
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    Effect of Reinforcement Ratio on Infiltration Behavior in Vacuum Infiltration of MgO-Al Composites With Lower Reinforcement
    (Gazi Univ, 2009) Pul, Muharrem; Calin, Recep; Citak, Ramazan; Seker, Ulvi
    In this study, MgO powders, with particle size 149 mu m were filled in steel tubes with 5 %, 10 %, 15 % volume fraction of reinforcement and liquid matrix alloy was vacuum infiltrated into MgO compact under same vacuum condition 550 mmHg, same time 5 min and at different temperatures and volume fraction of reinforcement. Infiltration distance was measured and microstructure and fracture behavior of composite was investigated. It has been found that infiltration distance and fracture strength were decreased with increasing volume fraction of reinforcement. Increasing matrix temperature also facilitates infiltration.
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    An investigation of surface quality of turning in al matrix mgo reinforced composite material
    (Gazi Univ, Fac Engineering Architecture, 2011) Pul, Muharrem; Çalın, Recep; Citak, Ramazan; Seker, Ulvi
    In this study; Al/MgO composites having 5 %, 10 %, 15 % volume fraction of reinforcement are produced by vacuum infiltration method and microstructure of composites are determined. Produced materials of metal matrix composite (MMC) machined with uncoated cemented carbide (WC), cubic boron nitrite (CBN) and coated cubic boron nitrite (CBN-C) cutting tools. The average surface roughness values (Ra) are determined by measuring surface roughnesses of composite samples. Ra values showed tendency to decrease by increasing cutting rate but it has proportionality with raising feed rates. The maximum roughness value is obtained at the cutting speed of 150 rev/min. It was observed that the most raugh sample is 15 % MgO reinforced sample. In terms of surface roughness 15 % MgO reinforced material is determined as the worst machinable sample. The best surface quality is obtained with WC cutting tool while machining 5 % and 10 % MgO reinforced samples and the best results are obtained 15 % MgO reinforced samples with CBN-C tools at high feed rates.