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Öğe An attempt towards green machining of Ni-based Hastelloy C4 alloy: Effect of vegetable oils and their combination with TiO2 and SiO2 nanoparticles on outputs(Elsevier, 2023) Yildirim, Cagri Vakkas; Sirin, Senol; Kivak, Turgay; Ercan, Hamdi; Sarikaya, MuratThe importance of nickel-based superalloys has increased day by day due to their use in special applications. However, the difficulties in the machinability of these alloys bring some concerns about parts quality and efficiency. Although researchers have tried ways (such as the use of high-performance cutting fluids) to overcome these challenges, their sustainability is still controversial. Therefore, this experimental research aims to contribute to the sustainable machining of nickel-based superalloys. In this regard, the present study investigates the effectiveness of vegetable-based fluids (sunflower, olive, hazelnut, and corn oils) and nanofluids (SiO2 + sunflower oil, SiO2 + olive oil, SiO2 + hazelnut oil, SiO2 + corn oil, TiO2 + sunflower oil, TiO2 + olive oil, TiO2 + hazelnut oil, and TiO2 + corn oil) during the machining of Ni-based Hastelloy C4 alloy. The study was carried out in three stages. In the first stage, all cutting fluids' pH and thermal conductivity values were measured. In the second stage, machinability tests were conducted under the prepared cutting fluids. Later, friction-wear tests of the cutting fluids that offered the best performance in the previous stage were done. As a result, the pH change was significantly increased with the addition of nanoparticles (TiO2 and SiO2) to corn oil. TiO2 nanoparticles allowed further improvement of thermal conductivity. Compared to dry machining, improvements of 58.57%, 34.88%, 53.18%, and 36.1% in surface roughness, cutting temperature, tool wear, and power consumption were achieved with corn oil+TiO2 nanofluid, respectively. It was determined that adhesion, BUE, BUL, and chipping were dominant damage types. Also, an adhesive is the dominant wear mechanism.Öğe Machinability performance of nickel alloy X-750 with SiAlON ceramic cutting tool under dry, MQL and hBN mixed nanofluid-MQL(Elsevier Sci Ltd, 2021) Sirin, Senol; Sarikaya, Murat; Yildirim, Cagri Vakkas; Kivak, TurgayNickel alloy X-750 which is difficult-to-machine material, is employed in many critical fields owing to its superior mechanical and thermal properties. However, these superior features lead to some difficulties in its machinability especially when using carbide tool materials. Hence, ceramic cutting tools (CCTs) having excellent hardness, heat and abrasion resistance, and poor chemical proximity to workpiece material are a perfect choice in machining operations of such materials. Considering this, the current study focused on the influence of various cutting environment, i.e., dry, base fluid-MQL without any mixed nanoparticles (BF-MQL) and hBN dispersed nanofluid-MQL (NF-MQL) on surface roughness, 2D-surface topography, maximum cutting temperature, cutting force, micro-hardness, flank wear and its mechanism when milling of alloy X-750 with Sialon ceramic tools. As a result, surface roughness was reduced by about 39% and 47.2% with BF-MQL (0 vol% additive) and hBN mixed NF-MQL, respectively compared to dry machining environment. Also the noticeable improvement with NF-MQL environment in 2D-surface topography of workpice, cutting temperature and cutting force has been achieved, the dry machining offered less tool wear for CCT than both BF-MQL and NF-MQL.Öğe Performance evaluation of MQL with AL(2)O(3) mixed nanofluids prepared at different concentrations in milling of Hastelloy C276 alloy(Elsevier, 2020) Gunan, Fatih; Kivak, Turgay; Yildirim, Cagri Vakkas; Sarikaya, MuratSince some deficiencies in mist lubri-cooling techniques i.e., minimum quantity lubrication (MQL) in heavy cutting conditions have been noticed, recently nano-cutting fluids which have enrich thermal conductivity than base fluid, are begun to be used in MQL system. One of the critical issues arising in this process is the addition of the appropriate nanoparticle ratio to the base liquid. Therefore, this study aimed to find the optimum distribution rate of Al2O3 nanoparticles having excellent properties and machining parameters. For this purpose, by adding Al2O3 nanoparticles to vegetable-based cutting fluid, nano-cutting fluids were prepared in different volumetric concentrations (0.5, 1.0 and 1.5 vol%). These prepared nanofluids were used in the MQL system when milling of Hastelloy C276. Three cutting speeds (60, 75 and 90 mirnin) and three different feed rates (0.10, 0.15 and 0.20 mm/rev) were added to the experimental design to study the performance of nanofluids under several cutting parameters. Apart from this experimental design, to clearly see the effect of concentration rates on tool wear and tool life, three experiments were carried out at each concentration ratio by keeping the machining parameters. Eventually, 1 vol% Al2O3 concentration clearly provided an improvement by up to 23% and 10% in tool life, compared to 0.5 vol% and 1.5 vol% concentration, respectively. In addition, while chipping/fracture, attrition wear and peeling of coating were observed under all cutting conditions, there was no evidence for workpiece material adhesion at 1 vol% and 1.5 vol% Al2O3 based nanofluid-MQL. (C) 2020 The Authors. Published by Elsevier B.V.Öğe Performance evaluation of whisker-reinforced ceramic tools under nano-sized solid lubricants assisted MQL turning of Co-based Haynes 25 superalloy(Elsevier Sci Ltd, 2021) Sarikaya, Murat; Sirin, Senol; Yildirim, Cagri Vakkas; Kivak, Turgay; Gupta, Munish KumarCeramics are widely used in machining of high temperature alloys i.e., Co-based Haynes 25 alloy due to its superior characteristics. The present paper is focused on the performance of whisker-reinforced ceramic cutting tool (WRCCT) under nano-sized solid lubricants dispersed in MQL (nanofluid-MQL) during turning of Co-based Haynes 25 alloy. The turning experiments were performed under several cutting environments (dry, base fluid MQL (BF-MQL), hBN based nanofluid MQL (hBN-NMQL), MoS2 based nanofluid MQL (MoS2-NMQL), graphite based nanofluid MQL Gr-NMQL) by varying cutting speed (200 and 300 m/min) and feed rate (0.1 and 0.15 mm/ rev) values. Initially, the viscosity and thermal conductivity of nanofluids were evaluated and then the prepared nanofluids were used for machining experiments. The results reveal that the rate of increase in thermal conductivity coefficient relative to base cutting fluid was 11.90% in hBN-nanofluid, 16.29% in MoS2-nanofluid and 14.12% in Gr-nanofluid. In terms of machining performance, on the one hand, the minimum surface roughness was obtained from Gr-NMQL assisted machining, on the other hand, the hBN-NMQL has been successful in limiting of notch wear and nose wear values. Compared to dry turning, the temperature was reduced up to 27.18% with hBN doped nanofluids, while it was 34.95% with MoS2 doped nanofluids and 29.32% with graphene doped nanofluids.Öğe Performance of cryogenically treated carbide inserts under sustainable cryo-lubrication assisted milling of Inconel X750 alloy(Elsevier, 2021) Sirin, Senol; Yildirim, Cagri Vakkas; Kivak, Turgay; Sarikaya, MuratOwing to their superior features even under elevated temperatures, the nickel-based superalloy Inconel X750 is among the materials demanded in many critical areas. However, such alloys are hard to cut because of their characteristic properties i.e., strain hardening, poor thermal conductivity, high mechanical resistance at elevated temperature, the presence of abrasive carbide fragments and chemical proximity. Therefore, it is important to develop the machinability characteristics of these materials with sustainable machining methods that offer high performance. For this, in this work, a number of attempts were made during the milling of the Inconel X750 alloy. During the experiments, the performance of each cutting tool was investigated by considering three different tools which are uncoated carbide tool, cryogenically treated cutting tool and TiAlN coated tool. Since the machinability of superalloys is difficult in the dry environment, three different sustainable cooling/lubrication conditions such cryogenic LN2, MQL and hybrid cooling/lubrication (MQL + LN2) have been used in conjunction with these tools. In evaluating the effectiveness of the employed methods, flank wear, tool damage types, surface roughness/topography, cutting force and maximum temperatures were analyzed. As a result, even if the cryogenically treated tool performed slightly better than those of untreated, it still did not reach the performance level of the TiAlN coated tools. The hybrid cooling/lubrication system with coated tool offered the best solution in terms of all criteria. On the other hand, MQL outperforms LN2 cooling for tool wear, surface roughness/topography and cutting force, LN2 cooling is better than MQL in temperature reducing.Öğe Study on turning performance of PVD TiN coated Al2O3+TiCN ceramic tool under cutting fluid reinforced by nano-sized solid particles(Elsevier Sci Ltd, 2020) Kivak, Turgay; Sarikaya, Murat; Yildirim, Cagri Vakkas; Sirin, SenolDue to their excellent chemical stability, hardness and abrasion resistance, ceramic cutting tools are suitable for operations at very high cutting speeds, which play a decisive role in high productivity. Thanks to these properties, they are significantly resistant to high temperatures occurred in the cutting zone. However, after a certain point, excessive temperature rise in the cutting zone brings some problems. This is seen as a problem that should be overcome as it affects negatively machining efficiency. However, the poor resistance of ceramic tools to thermal shocks is an important factor restricting the use of flood cooling. Alternatively, promising results have been achieved recently in MQL and nanofluid-MQL applications particularly on carbide cutting tools. When these methods are used together with ceramic cutting tools, the behavior of ceramic cutters and their effect on machinability outputs is still a matter of curiosity. Therefore, in order to observe the interaction between ceramic cutting tool and minimum quantity lubrication (MQL) and nanofluid-MQL, we investigated the turning performance of PVD TiN coated Al2O3+TiCN ceramic tool under dry, pure-MQL and nanofluid-MQL reinforced by nano-sized solid particles such as graphene nanoplatelets (GNPs) and multi walled carbon nanotubes (MWCNTs). Experiments were carried out to investigate the effect of cooling/lubrication (C/L) environment and cutting parameters on tool life, surface roughness and maximum temperature of chip. In addition, a series of experiments were also made to observe the effect of only C/L environment on the wear behavior of the ceramic tools and the machined surface topography while keeping the cutting parameters constant. As a result, pure-MQL contributed to the reduction of nose wear by about 69% compared to dry machining, while GNPs based nanofluid-MQL helped to reduce the surface roughness by 19.42%.