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    Öğe
    Effect of TiB2 and GNP reinforcements on machinability in drilling of Al7075/TiB2/GNP hybrid composites produced by powder metallurgy
    (Sage Publications Ltd, 2024) Yagmur, Selcuk; Pul, Muharrem
    In this study, it has been aimed to investigate the machinability performances by drilling by producing Al7075 matrix hybrid composite samples with graphenenanoplate (GNP) and titaniumdiboride (TiB2) reinforced at different rates by powder metallurgy. The impacts of GNP and TiB2 reinforcing materials on the cutting parameters and wear behavior of the cutting tool have been examined and discussed. As a result of the drilling tests which are carried out by applying different cutting parameters, it was observed that GNP additive has positive impact on the cutting forces, surface roughness, and hole quality in general. As a result of the machining experiments, the lowest cutting force was obtained as 150 N at a feed rate of 0.100 mm/rev and a cutting speed of 60 m/min in the 1% GNP reinforced sample. The minimum roughness value was obtained as 0.886 micron at 60 m/min cutting speed in the 1% GNP reinforced sample. The minimum deviations from cylindricality and circularity were also measured as 0.03 and 8.005 mm from the 1% GNP reinforced sample. While the lubricating effect was low with a GNP ratio of 0.5%, the abrasive effect was observed more with a GNP ratio of 1.5%. While GNP supplementation decreased the diameter deviation and cylindrical deviation values, it increased the perpendicularity deviation values. In general, swarf chip formation occurred with a small amount of flank wear on the cutting tools. While hard TiB2 reinforcement particles in the composite structure were effective in flank wear, the most important cause of chip formation was the presence of ductile aluminum matrix and relatively low cutting speeds. When the entire experimental study was evaluated, it was evaluated that the solid lubricant property of the GNP reinforcement material was effective at the most 1% GNP reinforcement rate.
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    Öğe
    Examination of the effect of B4C and GNP reinforcements on machinability in the machining of Al 6061 matrix B4C/GNP reinforced hybrid composites
    (Springer Heidelberg, 2022) Pul, Muharrem; Yagmur, Selcuk
    In this study, hybrid composite materials with Al 6061 matrix, boron carbide (B4C) and graphene nanoplate (GNP) being reinforced in different ratios were produced with the stir casting method. Afterward, machinability tests were carried out on the hybrid composites produced with the turning method. SNMG 12 04 08 NN LT 10 coded cutting tools were used in turning experiments. Experiments were realized at a fixed cutting depth of 1 mm, in dry machining conditions, using three different cutting speeds and three different feed rates. In the machinability tests, cutting forces and surface roughness values have been measured. At the same time, microscope images of the cutting tool tips were taken. When the data obtained as a result of the experiments were evaluated, it was observed that the cutting forces increased with the increase in the cutting speed, but the surface roughness values decreased to some extent. While the cutting forces increased with the increase in feed rate, there were no significant differences in roughness values and tool wear amounts. It was determined that the most effective parameter on cutting forces, surface roughness values and tool wear were constituted of the changes in B4C reinforcement ratio. It has been observed that the B4C reinforcement phase significantly increases tool wear. Besides, it was evaluated that GNP supplementation had a positive effect on machinability in some machining parameters and showed dry lubricant properties. It was concluded that the porosity and aggregation of the reinforcement element in the composite structure had a negative effect on the machinability properties. In addition, it was evaluated that it would be appropriate to use non-traditional manufacturing methods in addition to conventional machining processes in the processing of highly B4C reinforced composites.