Yazar "Gulesin, Mahmut" seçeneğine göre listele

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    Öğe
    Experimental and Statistical Investigation of the Machinability of Al-10% SiC MMC Produced by Hot Pressing Method
    (Springer Heidelberg, 2014) Ekici, Ergun; Samtas, Gurcan; Gulesin, Mahmut
    In this study, during the machining of metal matrix composites produced by a hot pressing method in CNC milling, the effects of cutting parameters and coating type on the surface roughness were experimentally and statistically investigated. The production of composite samples was accomplished by hot pressing, in which Al was used as the matrix element and 10 % SiC particles were chosen for the reinforcing phase. In the machining of samples, three different cutting tools (uncoated, multi-layered and Nano TiAlN coated), three different cutting speeds (60, 78, 101 m/min) and three different feed rates (0.04, 0.08 and 0.12 mm/rev) were employed. Full factorial (3(3)) experimental design was chosen for the statistical investigation of the cutting parameters and parameter interactions. The response surface method was used in the mathematical modelling of the surface roughness obtained from the experiments and in the optimisation of cutting parameters. At the end of the study, the cutting tool's wear was evaluated and the wear was discussed by comparison with similar studies.
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    Öğe
    Mechanical and fracture behavior of B4C reinforced Al composites produced by hot pressing
    (Carl Hanser Verlag, 2016) Ekici, Ergun; Ozcatalbas, Yusuf; Gulesin, Mahmut
    In this study, the effects of particle addition on the microstructure, mechanical properties and fracture behaviors of Al/B4C particle reinforced composite produced by hot pressing method were investigated. After the production of 5, 10 and 15 wt.-% of B4C reinforced composites, T6 heat treatment was applied. It was specified that a strong interface bond occurred between the matrix and particles, and during the fracturing of composites, this effect increased the particle fracture. It was observed that particles were fractured parallel to the fracture surface and to each other fracture surface of MMCp. In general, cavity of particle separated from the matrix was not seen. In the production of MMCp, it was also observed that hot pressing provided a density higher than 99 %. After the heat treatment the maximum hardness value of 173 HB was reached with 15 wt.-% B4C reinforced sample. The transverse rupture strength ( TRS) decreased with the increase of reinforcement ratio. The highest TRS was 510 MPa with the 5 wt.-% reinforced material, whereas the lowest value was obtained to be 387 MPa with the 15 wt.-% B4C reinforced material.
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    Öğe
    The machinability of Al/B4C composites produced by hot pressing based on reinforcing the element ratio
    (Walter De Gruyter Gmbh, 2016) Ekici, Ergun; Gulesin, Mahmut
    In this study, the effects of the particle reinforcement ratio on cutting forces and surface roughness were investigated when milling particle-reinforced metal matrix composite (MMCp) produced by hot pressing with different cutting tools. Alumix 123 alloy as the matrix material and B4C particles with an average size of 27 mu m and 5%, 10% and 15% ratio as reinforcing elements were used for the manufacture of composite materials. The experiments were carried out in dry cutting conditions with four different cutting speeds, constant feed rate and depth of cut. Changes depending on the increased reinforcement ratio in cutting forces and surface roughness values were investigated; the effects of 10% B4C reinforced composite on tool wear were also examined. It was observed that cutting forces increased with the increase in cutting speed and particle ratio with carbide cutting tools, and it was seen that the cutting forces on the cutting tools decreased when cutting speed decreased and the cutting forces increased as the reinforcement ratios increased. In addition, with increasing the cutting speed, the surface roughness of the machined surfaces of composite samples increased with the carbide tools, while the cubic boron nitride (CBN) tools have the opposite effect. While it was seen that flank and crater wear occurred on the cemented carbide cutting tools, abrasive, adhesive and other wear mechanism tools in addition to the main wear mechanism, no remarkable flank and crater wear occurred on CBN cutting tools.