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    Comprehensive analysis of cutting temperature, tool wear, surface integrity and tribological properties in sustainable milling of Ti6Al4V alloy: LN2, nanofluid and hybrid machining
    (Elsevier Sci Ltd, 2024) Sirin, Emine; Yildirim, Cagri Vakkas; Sirin, Senol; Kivak, Turgay; Sarikaya, Murat
    Despite being expensive and difficult to process, the Ti6Al4V alloy is a vital component for crucial industries. To improve its machinability and accomplish sustainable production, environmentally friendly cooling and lubricating agencies are used. Studies on the machinability of the alloy are still necessary because of its unique features and significance in vital industries like aerospace, defense, and medicine. Therefore, this investigation focuses on tool wear, temperature, and surface integrity for sustainable milling Ti6Al4V under various machining environments, i.e., dry, pure-MQL, LN2, 2 , hBN, CuO-doped nanofluids, and hybrid methods. The produced nanofluids' thermophysical and rheological characteristics were examined in the study's initial phase. Because of the results from the first stage, machining performance indicators were assessed in the subsequent milling experiments. As a result, CuO-doped nanofluids gave improved results in terms of viscosity and pH. The best results obtained in the LN2 2 + CuO hybrid cooling lubrication environment in important machinability outcomes such as tool wear and surface integrity were attributed to the rheological properties of CuO-doped nanofluid and its harmonious cooperation with LN2-cryogenic 2-cryogenic cooling.
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    Öğe
    Experimental research on sustainable drilling of Hastelloy X superalloy: Impact of hBN, GNP, LN2 and hybrid eco-friendly cooling/ lubrication strategies
    (Elsevier Sci Ltd, 2024) Sirin, Emine; Yildirim, Cagri Vakkas; Kivak, Turgay; Sirin, Senol; Sarikaya, Murat
    In this study, the effect of sustainable cooling and lubrication strategies such as MQL, LN2, LN2 +MQL, LN2 +hBN/GA, LN2 +GNP/GA, LN2 +hBN-GNP/GA on drilling nickel-based Hastelloy X alloy was examined. The environmental impacts and health risks of traditional petroleum-based cutting fluids used in drilling operations have led researchers to look for ecological alternatives. In this context, combinations of nanofluids enriched with minimum quantity lubrication (MQL), liquid nitrogen (LN2), and nanosized hBN and GNP particles have been tested. The experiments were carried out at cutting speeds of 20 and 30 m/min and feed rates of 0.04 and 0.06 mm/rev. Nanofluids characteristics i.e., viscosity, Ph, thermal conductivity and wettability, and drilling performance were evaluated with criteria such as cutting force, surface roughness, hole quality and tool wear. The results obtained showed that the hybrid methods combining LN2 and nanofluid-based MQL provided superior performance in terms of both cooling and lubrication, and the condition directly positively affected the processing outputs. This study contributes to the literature by revealing the potential of ecological cooling/lubrication methods in the sustainable production of difficult-to-machine materials such as Hastelloy X.
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    Öğe
    Performance and wear analysis in machining of Co-based Haynes 25/L605 superalloy using sustainable cooling/lubrication agencies
    (Elsevier, 2025) Sarikaya, Murat; Yildirim, cagri Vakkas; Sirin, Senol; Kara, Muhammed Ikbal; Sirin, Emine; Kivak, Turgay; Krolczyk, Grzegorz M.
    The cobalt-based Haynes 25 superalloy is a key material in sectors such as aerospace, medical, and energy, known for its outstanding high-temperature strength, wear and corrosion resistance. However, its low thermal conductivity and rapid work hardening rate make it inherently difficult to machine, highlighting the need for new cooling and lubrication methods. This work investigates the machinability of Haynes 25 under various sustainable cooling and lubrication techniques, including dry conditions, minimum quantity lubrication (MQL), nanofluids, and cryogenic COQ. Additionally, hybrid systems combining cryogenic COQ with nanofluids are also being investigated. The effectiveness of these approaches was ascertained by thorough investigations of surface roughness, cutting temperature, tool wear, and its mechanisms, and power consumption. Experimental results show that hybrid cooling systems especially those including nanofluids and cryogenic COQ significantly improve machining performance. Compared to dry machining, these methods minimized tool wear by 38 % and achieved up to a 44 % reduction in cutting temperature and a 32 % reduction in power usage. These results were a result of the enhanced thermal and tribological characteristics of nanofluids along with COQ's fast cooling capacity. This work provides a route toward sustainable and high-performance manufacture of challenging-to-machine materials by highlighting the possibilities of hybrid cooling strategies to maximize machining efficiency, extend tool life, and lower environmental impact.