A REVIEW ANALYSIS OF ELECTRICAL-DISCHARGE MACHINING OF VARIOUS NICKEL-BASED SUPERALLOYS

e-ISSN: 2582-5208 International Research Journal of Modernization in Engineering Technology and Science Volume:03/Issue:03/March-2021

Impact Factor- 5.354

www.irjmets.com

A REVIEW ANALYSIS OF ELECTRICAL-DISCHARGE MACHINING OF VARIOUS NICKEL-BASED SUPERALLOYS Sneharsh Bhikaji Sawant Dessai*1, Souradeepta Prusty*2, Patel Tanmay Dipakkumar*3, Rahul Kumar Agrawal*4, Jeeva P. A.*5 *1,2,3,4Student,

Department of Mechanical Engineering, Vellore Institute of Technology, Vellore, Tamil Nadu, India.

*5Faculty,

Department of Mechanical Engineering, Vellore Institute of Technology, Vellore, Tamil Nadu, India.

ABSTRACT In the current scenario, high accuracy and quality are not only expected but also a minimum of production time.

To do this, process parameters must be varied as required and requires knowledge of the optimal input parameter values for optimizing the objective. Research on Electrical Discharge Machining of Nickel Superalloys such as Waspaloy alloy, Inconel alloys, Nimonic alloys, and Rene alloys was noted for their high species strength and resistance to corrosion at high temperatures, has been discussed here. Analysis of various testings such as Metal Removal Rate (MRR), Surface Roughness, X-Ray Powder Diffraction (XRD), Scanning Electron Microscopy (SEM), and Tool Wear Rate on nickel-based superalloys has been mentioned. This can be readily used by future researchers and can add the mentioned Nickel-based superalloys to the sparse EDM database.

Keywords: Electrical Discharge Machining (EDM); Waspaloy; Inconel alloys; Nimonic alloys; Rene alloys; Surface Roughness.

I.

INTRODUCTION

An alloy with the potential to work at a high percent of the melting point is a superalloy or high-performing alloy. A superalloy's many main features are its excellent mechanical strength, thermal cramping resistance, corrosion resistance, and high surface stability.

The composition of the crystal is normally face-cantered cubic (FCC) austenitic. For instance, Waspaloy, Pyromet 860, Nimonic, Haynes 230, Hastelloy, Inconel, TMS alloys, Rene alloys, MP98T, Incoloy, Udimet, CMSX single crystal alloys, and TMS alloys are examples of such alloys. The production of superalloys has depended heavily on advances in both chemicals and processes. High-temperature strength development of superalloys is achieved by solid solution and precipitation strengthening.

Superalloys achieve high-temperature strength by improving the solid solution and strengthening secondary precipitation, including gamma primary and carbide. Elements such as aluminium and chromium shall have oxidation or corrosion resistance. Superalloys are also cast as a single crystal, which reduces cramp resistance when the grain limits provide strength in low temperatures. In aerospace and marine turbine engines the principal application is for such alloys. In gas turbine blades, Creep is usually the life-limiting factor. Superalloys are the materials that make a lot of engineering technology very high in temperature possible.

Electrical discharge machining is a method of metal machining, using electrical discharges the desired form is produced. A set of increasingly repetitive electric current releases material from the workpiece lying between the two electrodes that are separated from the workpiece using a dielectric fluid and are subjected to a specific electric voltage. One electrode is the electrode of the instrument or just the tool, and the other is the electrode of the piece of equipment. The procedure will rely on the absence of physical contact between the instrument and the workpiece.

www.irjmets.com

@International Research Journal of Modernization in Engineering, Technology and Science

[473]

e-ISSN: 2582-5208 International Research Journal of Modernization in Engineering Technology and Science Volume:03/Issue:03/March-2021

Impact Factor- 5.354

www.irjmets.com

Figure 1. (a) Schematic diagram and experimental configuration of the Inconel 800 EDM machine

Figure 1. (b) Model of thermo-electric machining method for EDM.

II.

METHODOLOGY

Taguchi’s Method Taguchi helps to cut down the cost and time of doing experiments, which is why researchers very much use it to optimize the process and obtain the exact result. Taguchi proposed to measure the variation in method, named Orthogonal Array (OA) and also Signal-to-Noise (S/N) ratio. The OA is used to analyze the process parameters at various experimental levels and to decrease the number of experiments. The S/N ratio is used to record any noise (deviations) from the desired results. The bigger the value S/N is, the better the process because it can help make a more robust process. The response of Surface Roughness (SR) with low value shows good performance of machining and is called ‘smaller-the-better’. The response of MRR of high value shows good performance of machining and is called as ‘larger-the-better’. The S/N ratios for ‘larger-the-better’ and ‘lowerthe better’ response are shown by the following equations, [1]

Where, The experimental value of the S/N ratio is represented by ῃ The experimental value of the ith experiment is represented by yi The total number of experiments is represented by n.

The greater the value of ῃ the feasible is the response level. The Taguchi method suggests fewer experiments and provides the results for the entire factorial design of experiments. The desired output is provided by www.irjmets.com

@International Research Journal of Modernization in Engineering, Technology and Science

[474]

e-ISSN: 2582-5208 International Research Journal of Modernization in Engineering Technology and Science Volume:03/Issue:03/March-2021

Impact Factor- 5.354

www.irjmets.com

introducing different parameters without increasing the test run in the modified Taguchi method. The Taguchi method can be used to achieve the optimal solution [2].

III.

WORKPIECE MATERIALS

3.1 Waspoloy Waspaloy, a superalloy made from nickel, is a material that has a high corrosion resistance at high temperatures, thermo-mechanical fatigue and shocks, creep, erosion, and relatively impermeable to oxidation and thus suitable for use in extreme conditions. Nickel-based superalloys are mainly used in spacecraft engine manufacturing and gas turbine compartments. Nuclear reactors and petrochemical plants also use these superalloys. There are almost negligible numbers of scientific studies on this subject and there is a lot of scope in this area[3].

Figure 2. The microstructure of Waspaloy at different temperatures.

3.1.1 Properties It has a Specific gravity of 8.25 and a density of 8138 kg/ cubic meter. The modulus of Elasticity for Waspaloy is at 211 x 103 Mpa at 25 Deg C (77 Deg F) and 200.6 x 10 3 Mpa at 260 Deg C (500 Deg F). The mean coefficient of thermal expansion varies from 12.2 x 10-6 /°C at 93°C to 13.1 x 10-6 /°C at 316°C. Waspaloy has a specific heat of 0.52 kJ/kg-K at 93°C and 0.54 at 538°C. Its chemical properties vary significantly from Inconel 718 with an iron and cobalt content of approximately 13% wt. of cobalt and 1% wt. iron in Waspaloy, while Inconel 718 has a slightly higher composition of 17% wt. iron with 1% wt. of cobalt. It has alloying-elements for hardening heat treatment including aluminium and titanium. With temperatures of up to 700 pounds, Waspaloy has useful power.

3.1.2 Application Waspaloy is mostly used in extreme environments. It is commonly found in gas turbine blades, rings, shafts, turbine disks, and seals. The material used in X-ray fluorescence spectroscopy is made from Waspaloy.

3.2 Inconel Alloys The specimen was made of the Inconel 718 alloy. Nickel chromium alloys are often referred to as Inconel. It's a precipitation-hardenable substance that's often used in wrought products. It is highly weldable for high material strength and offers good tensile properties with high ambient, cryogenic and high temperatures. The most common applications include aircraft turbine engines, rocket engines, and nuclear reactors. This material was created in the late 1950s by the International Nickel Company. High tensile production and age-hardening characteristics of stability for the material was the main objective[4].

3.2.1 Properties Inconel 718 alloy at room temperature comprises good mechanical characteristics, which has a tensile strength of 1358 Mpa which is quite high compared to its other alloys, it also has a great yield strength of 1137 Mpa. The modulus of elasticity, in this case, is 32 x 103 Mpa.

www.irjmets.com

@International Research Journal of Modernization in Engineering, Technology and Science

[475]

e-ISSN: 2582-5208 International Research Journal of Modernization in Engineering Technology and Science Volume:03/Issue:03/March-2021

Impact Factor- 5.354

www.irjmets.com

The zinc coating on zinc-coated brass wire boils off or vaporizes during the machining process, helping the wire to cool down and bring more energy to the area of operation. The paper also suggests a higher flush capacity for zinc-coated brass electrodes.

Current 1 amp, pulse on-time 0.98 s, pulse off time 0.03 s, tooling material 0.31, and polished particles 0.64 are the optimal composite of parameters for Inconel 800 responsiveness optimizations. The current, timely pulse and tool material affect the integrity of the machined specimen, leading, as seen in SEM micrographs, to the development of debris, deep craters, cracks, and pockmarks.

A major grain refining was observed on Inconel machined surfaces 625, 718, and 825 as a thermal-mechanical effect of the EDM process. Due to the grain processing, the density of micro trains and dislocations also increased. On the machined surface of Inconel 601, however, grain growth has been observed[4].

3.2.2 Application The sample was made using a flat sheet specimen as sheet material is used to manufacture most components within the avionics and aerospace industry. When the zinc-coated brass wire is applied as an electrode material, the core error is reduced by a significant amount of 21.89 percent compared with the uncoated brass wire.

Because of its improved flush ability, the zinc-coated brass electrode was chosen[5].

3.3 Nimonic alloys NIMONIC was first produced in England in 1940. Commercially available are the NIMONIC 75, NIMONIC 80A, 81, 86, NIMONIC PE11, and 16 alloys. The NIMONIC 80A is an alloy made with additional additives like titanium, aluminium, and carbon. Nimonic alloys are renowned for their high specific resistance and high-temperature corrosion resistance. Nimonic C-263, for this particular study, is more focused on the other alloys. Wire electricity discharger (WEDM), which can produce tough and intricate forms of exotic material, has been gaining popularity in the industry. regardless of hardness. Due to its high hardness and tool wear rates, conventional Nimonic C-263 super-alloy machining is very onerous and difficult, and the necessity of WEDM is involved.

Figure 3. Schematic view of Nimonic C-263 WEDM 3.3.1 Properties The strength to weight ratio of these alloys is very high and resistance to creep is also significant[6–8]. Nimonic C-263 superalloy provides a range of excellent mechanical properties including resistance at very high temperatures, high specific strengths, higher thermal-fatigue, and corrosion.

3.3.2 Applications Nimonic alloys are desirable to use on jet engines in aircraft’s hot sections and gas turbine components, for instance where noise and heat are high, such as turbine blades and exhaust nozzles[9].

www.irjmets.com

@International Research Journal of Modernization in Engineering, Technology and Science

[476]

e-ISSN: 2582-5208 International Research Journal of Modernization in Engineering Technology and Science Volume:03/Issue:03/March-2021

Impact Factor- 5.354

www.irjmets.com

3.4 Rene alloys Rene80 is high strength and durability nickel super-alloy that is oxidation-resistant and high creep strength at high temperatures. With high hardness and low thermal conductivity, traditional machining of Rene80 often results in different deformations such as tool wear, the development of a built-up edge is also disadvantageous.

For these super nickel alloys, non-traditional techniques such as Electrical Discharge Machining (EDM) for better measurements and surface smoothness are also applied[10].

3.4.1 Properties Rene 80 has a density of 7700 kg/m3 and high mechanical properties. The young modulus amounts to around 200,000 MPa. The strength of the tensile is 650-880 MPa. 275 MPa fatigue and 350-550 MPa output power. Rene 80 thermal conductivity is approximately 25 W/m.K and 460 J/kg.K special heat. It also has a high melting temperature which is 1450-1510 °C and 0.55 ohm.mm2/m resistant.

3.4.2 Application It is used for the manufacture of hot jet engine parts, primarily gas turbine blades, in the aerospace industry.

Often used for bolt, springs, and missile parts.

IV.

ELECTRODE MATERIALS

Wire machining is a non-traditional method used to produce conductive hard metal conductive materials with complicated shapes, higher precision, and tolerance. WEDM uses an electrode in wire form that is constantly moving[11]. Various materials are used to make the electrodes, such as copper, cubicles, zinc-coated, etc. The range is 0.050–0.35 mm in diameter. A straining device is maintained to resolve the machined inaccuracies in the components and is supported by a pair of jobs that stand in front of the workpiece. A series of electrical discharges shall remove the material[12,13].

Figure 4: WEDM process.

4.1 Properties of wire electrodes The properties necessary for the electrode wire are geometrical, electrical, mechanical, and physical properties[14]. For continuous, high energy and high-speed cutting, electrical output is required. The electrical characteristics of the electric resistance are articulated. The use of two current-contacts along with the selection of high-level electrode materials, for example, brass, aluminium, copper, and their alloys, with optimized settings would reduce energy loss. The conductivity of the electrodes determines how easily the energy provided from the power supply to the cutting-point is transferred. The most significant features based on the EDM models, to control WEDM performances are heat resistance to high temperatures at the output, stable electrical output for cutting at high-speed and accurate processing, and low clarification to control the surface heat[15].

Improving the wire surface allows quicker cutting. The layer-structure of the electrodes is influenced by the thermophysical properties of their thermal conductance, melt, and evaporation temperatures. The wire coating www.irjmets.com

@International Research Journal of Modernization in Engineering, Technology and Science

[477]

e-ISSN: 2582-5208 International Research Journal of Modernization in Engineering Technology and Science Volume:03/Issue:03/March-2021

Impact Factor- 5.354

www.irjmets.com

initiates the cooling and good cutting efficiency of the wire electrode[16]. The flexural strength, tensile strength, and straightness are the essential properties of the electrodes. High tensile means the wire electrode's ability to withstand stress during machining. Straightness is critical when Auto Threading is productive[17]. The soft wires (Tensile strength= 350–400N/mm2) are used in the cutting of conveyors and for the cutting of highprecision wires (Tensile Strength= 750–990N/mm2)[18]. The machinability of the WEDM method is also enhanced by factors not connected to the wire, such as the principle of a mechanical machine, improved impetus generators, and dielectric spinning techniques[19].

4.2 For Inconel alloys Most of the studies on EDM of Inconel 718 use a tubular cross-sectioned and having 99.9% purity of copper electrode or Graphite rod of cylindrical shape with 12mm diameter as tool electrode. WEDM is an innovative method for material removal with a narrow copper wire as the electrode tool. The di-electric medium of kerosene-deionized water separates the workpiece and the electrode. The movement of the wire through the part causes spark releases and erodes the part to achieve the desired shape[20].

Another test shows that the measurement of the corner surface (μm2) is more important due to the diameter of the wire electrode in the smaller corner area. Therefore, corner angles of different wire electrodes are considered for minimizing this die-corner defect, to see the effect of the wire electromagnetic surface on corners and controllable variables (flushing stress, wire voltage, pulse time), selected to adjust the cross-section of the job[21].

Literature shows that there is an indirect proportionality between the surface roughness and the melting point of the electrode wire instrument. The crater size and surface of the instrument at all times are distinguished by surface roughness[22]. If the zinc layer has a lower melting point than the inner cube electrode in the zinccoated cube wire, the external zinc cools the wire temperature and transforms the most energy available for working While processing[14]. The zinc-coated electrode of the metal wire generates less Surface roughness of Inconel metal wire 718 uncoated electrodes. The evaporation of the coating increases the distance, leading to improved removal of debris that can minimize surface roughness.

Figure 5. Displaying the surface roughness effect of the wire electrode 4.3 For Nimonic alloys In the Literature of EDM of Nimonic75, many researchers used disk electrodes made of copper with a rotatory motion. The process-parameters taken into account are the peak current and rotary speed. The electrode in Wire-Cut EDM (WEDM) is a copper metal wiring, which operates at the speed of 0.005 to 0.003 cm. MicroEDM(m-EDM) is one of the most favourite techniques in the production of micro features. The electrode dimensions are below 1 mm.

The EDM literature of Nimonic alloys contains scant details. In the Die sinking EDM, de-ionized water, EDM 50 oil, and wire electrode material is the dielectric materials used: zinc-coated wire of brass and brass, cryogenically treated of molybdenum and brass. www.irjmets.com

@International Research Journal of Modernization in Engineering, Technology and Science

[478]

e-ISSN: 2582-5208 International Research Journal of Modernization in Engineering Technology and Science Volume:03/Issue:03/March-2021

Impact Factor- 5.354

www.irjmets.com

4.4 For Rene alloys The copper electrode is used for research into multi-response optimization of rotary EDM on RENE80. Results from ANOVA show that electrode peak current and rotational speed contribute significantly to different output responses. The material is machined with pure copper with a purity of 99.97 percent, and an electrode in diameter of 14 mm. It has an 8.93 g/cc density and 396 W/m0K heat conduction. With a speed control device, the rotating speed of the electrode can vary from 0 to 500 rpm. With the aid of the servo mechanism, a rotating solid electrode is fed down into the workpiece. The electrode and working part's polarities are set to negative and positive, respectively. The tool is usually made anode to minimize the tool used for both the copper electrode and graphite; however, if substantial removal is necessary, the tool is made cathode, but thus, wear of tools increases. Polarity, therefore, has a serious influence on processing time and needs to be examined. For multi-response optimization, max current and electrode rotational speed have been observed. The maximum current is 76.60% following the rotatory electrode speed of 15.65% with the rotational electrode speed of 500rpm.

V.

TESTS CONDUCTED ON THE SPECIMEN

5.1 Inconel Tests 5.1.1 Fatigue testing In this investigation, a mechanical load maintainer was employed with a straight voltage compression fatigue measurement system. The machine is preloaded by a static force motor and a rocket and chain drive transmission reducer. The cyclic load can be set by hand to a maximum of 45 KN. The unit's test frequency was maintained at 30 Hz (1800 cycles per minute). In this analysis, a stress ratio of R=0 was used. Many of the experiments were carried out at room temperature. The study found that the fatigue life of the machined specimens decreased slightly with changes in cutting speed, although they remained unchanged[23].

5.1.2 Surface Roughness and its Examination Both parent and machined specimens were cut into small pieces measuring 6.5 x 6.5 mm. The pieces have been ultrasound washed and air-dried in an aqueous methanol solution. With optical and scanning electron microscopes, the device surfaces were viewed in various quantities. A 94B Bendix profilometer with an amplimeter, VB pilator, and Ft skid mount LK tracer shape was used for measuring surface roughness. A 16.25 mm tracer stroke was used with a selected 0.30 mm cut-off. Roughness experiments were carried out on the specimens in addition to the relative movement of the work-tool. Both the parent metal and the EDM-machined specimens were checked for surface roughness. On each specimen, at least five measurements were taken, with the average used as a reference.

With a change in the cutting speed, though, the microhardness and ruggedness of the machined surfaces increased slightly. EDM has established a hard recast layer, causing increased hardness and roughness, when examining machined surfaces by optical microscopy. The fracture patterns were identical when the broken surfaces were shaped at different cutting speeds.

Wire electrode material has an impact on the MRR during machining of Inconel 718. If the surface roughness values of the zinc-coated metal wire electrode are compared to that of an uncoated metal wire electrode.

According to the literature, the melting point of the electric wire instruments is indirectly proportional to the roughness of the surface. The roughness of the surface of the crater and the surface of the tool is described. The external zinc layer, with a lower melting point than the inner metal wire electrode, cools the wire temperature of the external zinc layer and during the process converts more energy into the working area. Since the evaporation of the coating widens the void, more debris is removed, and the surface roughness is reduced.

Inefficient splashing characteristics and the nonuniform thermal load in the brass wire are caused by nonuniform spark formation. Improper flushing can also result in the creation of an arc, which can wreak havoc on the surface finish.

To improve surface resistance and corner error during WEDM on Inconel 718, the choice of the right electrode material is crucial. Inconel 718 significantly improved MRR, surface roughness, and the corner error with zinccoated wire from the uncoated wire of a metal. The most important parameters affecting the response variables www.irjmets.com

@International Research Journal of Modernization in Engineering, Technology and Science

[479]

e-ISSN: 2582-5208 International Research Journal of Modernization in Engineering Technology and Science Volume:03/Issue:03/March-2021

Impact Factor- 5.354

www.irjmets.com

are pulse time and discharge current. Its pulse-on time and discharge current were the most important influence on MRR. Pulse-on-time and flushing pressure was most affected by surface ruggedness. Corner precision was almost unaffected by sparking factors. Surface ruggedness increases with increased maximum current and increased cabling stress. In the Inconel 601 alloy, 0.8 meters was achieved with the best surface finish (Ra).[24].

Figure 6. The EDM Inconel 601, obtained at parameter setting, SEM microscope shows surface irregularities: [Vg=60V, IP=11A, Ton=500μs, τ=85%, Fp=0.6 bar] 5.1.3 MRR For the design of the Inconel-800 experiments, RSM's box-Behnken method was considered. The most important factors for MRR, according to the study, are present, pulse on-time, and tool content. Pulse off-time affects both reactions little, while powder particles affect the MRR. The MRR was 4,033 mm3/min to 35,788 mm3/min. For the material removal rate, the difference between experimental and expected values is 9.8%[25]

.

Figure 7. (a) MRR peak current effect, (b) Ra peak current effect, and (c) Surface Crack Density(SCD) peak current effects. www.irjmets.com

@International Research Journal of Modernization in Engineering, Technology and Science

[480]

e-ISSN: 2582-5208 International Research Journal of Modernization in Engineering Technology and Science Volume:03/Issue:03/March-2021

Impact Factor- 5.354

www.irjmets.com

5.1.4 TWR (Tool Wear Rate) In the Inconel-800 PMEDM process, the TWR was developed to connect current, pulse on-time, pulse-off-time, tool content and powder particle machining parameters. The range of TWRs is between 0.002 and 1.957 mm3/min. There is less than ±8.5% difference between the experimental and the expected tool wears[25].

5.1.5 Energy Dispersive X-Ray Spectroscopy(EDS) analysis Due to the deposition of the carbon material from the system electrode to the machined surface in Inconel-800, the weight of carbon is increased by the graphite electrode from 13.55 to 20.31. On the machined surface, the formation of oxides can also be seen. The degradation of EDM fluid results in oxidation in the presence of oxygen. Besides carbon, the work-surface parts were deposited with other elements, such as nickel, aluminium, silicones, chromium, and iron oxygen. There have also been strong nickel and iron peaks in the EDS spectrum [25].

5.1.6 XRD analysis After the machining, carbon particles migrate and shape different compounds onto the machined surface.

Compounds like Ni(CO)4, NiO, Cr(III) O3, Cr(III) 2O3 were found in the XRD analysis on the Inconel-800 surface, in two positions with different d-value intensities. The energy is taken away from the work surface during the EDM process. The work material in the machining area can react both with debris from the electrode and wear material. Carbon enhancement is also aided by dielectric fluid pyrolyze on the machined surface. These factors can facilitate the migration of materials to the machined surface. Intermetallic compounds and carbide precipitates are part of the XRD of the machined surfaces. Several CO2 were discovered in various crystallographic directions in the EDM surface specimen, including Ni3(Al, Ti), CoCx, NiC, and AlNi3C0.5. In the EDM surface of Inconel 625 and 718, Ni8Nb formation was seen in various crystallographic directions [25].

Figure 8. X-ray diffraction machine 5.1.7 Volumetric Material Removal Rate(VMRR) WEDM has demonstrated its capacity to machine Inconel 601 at a surface finish (Ra, less than 1 μm) at a volumetric removal rate of 8 mm3/min. With increasing peak current and water pressure, the volumetric deletion rate usually increases. This pattern is kept until the bows are created, then the maximum current increases and decreases VMRR [25].

5.2

Nimonic Tests

5.2.1 Surface characterization Over the expected life of the material, surface integrity affects product consistency. After the EDM process is carried out, the surface structure is affected by melting and vaporization, followed by a re-solidification of the substrate from both electrodes. The appearance of craters, holes, debris, recast layer thickness (RLT) can be seen in various forms. The work in this section deals with the analysis of the machining of machined surface's surface quality using various techniques such as SEM, XRD, and EDS[26].

www.irjmets.com

@International Research Journal of Modernization in Engineering, Technology and Science

[481]

e-ISSN: 2582-5208 International Research Journal of Modernization in Engineering Technology and Science Volume:03/Issue:03/March-2021

Impact Factor- 5.354

www.irjmets.com

5.2.2 SEM, XRD, and EDS analysis of Nimonic alloys.

A study of Nimonic 75 EDM and SEM found that, while the tool polarity is positive, a thicker recast substrate of globules, an irregular surface with a higher proportion of carbon, and lower deposits of materials exists[27,28].

In WEDM of Nimonic-75, there are large craters with higher dump energy, matt surface aspect, lumps of debris, and microcracks. Under low energy input conditions, superficial consistency is higher than under high energy input conditions under which several integrated edge layers are present along with the rough surface (thicker refilling layer) of Nimonic-80A in Wire Electrical Discharge machining processes.

The microstructural study by Nimonic 80A reveals that stronger superficial quality is seen in low inputs of energy than high conditions in which the red surface in the cut-off WEDM process is observed[29]. In the EDS analysis, Nimonic 80A was found in the WEDM stage, with the migration of zinc and copper from the instrument and lower release energy being relatively less. To equate Nimonic 80A microstructures to an abrasive mixed electrical discharge diamond surface grinding(AMEDDSG) of the surface machined by the use of pure dielectric cavities has large surface cavities [30].

SEM research shows that Nimonic 80A has flawless craters on surfaces machined with a cryogenically processed wire during the WEDM operation. Comparative research shows that the Nimonic-90 machined surface is equipped with big depth craters and trim action after raw cuts lead to smaller defects and micro-cracks[31,32].

In the Nimonic 75 EDM process, XRD analysis showed the increase of the carbon content of the layers affected.

The SEM analysis indicates that the RLT and microcrack concentrations with lower AR have decreased. In the EDM Nimonic-90 parameter setup, better hollows are given by the optical micrograph images. Upon review, a raw WEDM cut from Nimonic C 263 can be observed for the microvoids and the cracks. The RLT is eliminated but the stress, microevasion, and deposition of the tool wire cannot be minimized. Grinding is followed by grinding, which improves the surface integrity and substitutes for the recast layer.

At high energy inputs, there is a relatively higher transfer of atoms and thicker refurbishment layers, whereas at a low energy input the development of craters is low and the surface is flat, as seen by the SEM study. The XRD study shows the tensile nature and various compounds are present in the residual stresses. The multi-cast technology in Nimonic C-263 used in the WEDM and substantial changes are being made with irregular deposition, reducing the thickness of the recasting layer and increasing the surface finish. Nimonic 80A SEM photographs display less grinding signal but higher cavities at higher speeds in the abrasive-mixed electrical discharge diamond grinding (AMEDDG).

Figure 9. XRD analysis of the machined surface 5.2.3 Recast layer thickness and EDS analysis of Nimonic C-263 superalloy Oxygen was also found on the external machining surface through EDS study with the high carbon level of dielectrical ionization in addition to the base material. The accumulation of the reshaping coating on the surface of the workmanship is not favourable for aerospace industries applications. Thus, at lower Es (i.e., Spark energy), this rework layer was reduced substantially. On the external surface of the machining was shaped a recast layer with low thickness and fewer transmission of foreign atoms than higher Es. Similar findings indicated that a www.irjmets.com

@International Research Journal of Modernization in Engineering, Technology and Science

[482]

e-ISSN: 2582-5208 International Research Journal of Modernization in Engineering Technology and Science Volume:03/Issue:03/March-2021

Impact Factor- 5.354

www.irjmets.com

dense refurbishing coating of the high percentage of alien elements (Cu, Zn, C, and O), relative to a lower pulse on-time, has been accumulated in the processed surface at higher pulses. On the machined surface a dense recast coating was mounted at a higher energy level compared with a lower energy level.

5.2.4 XRD phase analysis of Nimonic C-263 superalloy The XRD pattern on both the lower and higher surface of the machining Es. The surface of WEDM includes the different compounds found by XRD-summary review Fe1.2Ni0.8, Fe1.5Ni0.5 and Co0.06Fe0.94, and Alo.29Ni0.27Ti0.44. Titanium and nickel are responsible for their high reactivity, particularly for the creation of different compounds. XRD machined surface pattern reveals that with the rise in Es the peak amplitude was reduced. The crystal surface size has since been reduced to higher E, but only the direction of the desired crystal form remains unchanged. The change of peaks in the XRD pattern also takes place on the right side, indicating that the surface of the Nimonic C-263 superalloy contains residual tensile strain after WEDM. 5.3 Rene Tests 5.3.1 Effect of process parameters on MRR MRR is proportional to pulse on-time depending on the input discharge capacity. MRR, of course, should increase in time as the pulse increases, but this is not so technically because this alloy has carbides such as MC, M23C6, M6C, and M7C3 carbohydrates where M represents different metal elements, which melt and solidify at high pulse on time, in the alloy. As pulse off-time increases, the dielectric gets enough time to wipe this debris away, which leads to efficient functioning and stabilization of the process.

5.3.2 Effect of process parameters on SR With increased peak current, pulse in-time, and pulse off-time, SR increases. There are reasons for this increase.

With the increase of current a single spark energy increases and thus striking forces occur on the surface, creating deep and wide craters and higher SR [33]. At lower current value, the craters are shallow and narrow, making SR low. With pulse in-time, the SR starts to increase. The input energy is transferred to the workpiece, i.e., the heating temperature is increased with the long pulse in-time. The SR is improved by a small proportion with a pulse off-time increase. As the pulse off-time increases, sparks decrease and reduces the craters overlapping.

5.3.3 Effect of process parameters on White Layer Thickness (WLT) With the rising current, the WLT rises. More heat is transferred to the surface of the parent matter, which quickly leads to the melting point of the surface temperature and removes high amounts of the molten material.

At the same time, Dielectrics cannot gradually discharge all this molten material because Dielectric can discharge only fixed molten material at constant pressure, i.e. the delete rate is greater than the discharge rate.

On the surface of the parent, excess molten materials are piled. WLT increases with the increase of peak current.

High WLT leads to a higher time pulse. The off-time pulse effects on the WLT are insignificant, as material and surface residues are not removed during pulse off-time.

5.3.4

Effect of process parameters on SCD

In comparison with the pulse in-time, peak current is more effective for SCD. With peak current and pulse in time, SCD decreases linearly. SCD is high at a lesser value than WLT, and so the white layer[34] region is low.

SCD is high. The thickness and area of the white layer increase with increasing peak current. This is seen at a lower SCD value, as in the same part to white layer the length of cracks does not increase. The tension rises with the highest current, but there is not much increase. At higher currents, due to massive heat dissipation, the surface cracks widen, thereby removing the same amount of inner stress. The SCD is more or less the same with increased pulse off-time because no material deposition is made during pulse-off-time on the machined surface and thus there is no pulse-off-time change of SCD.

VI.

CONCLUSION

In this review paper, we show a state-of-the-art assessment of EDM research developments in nickel-based superalloys such as Waspaloy, Inconel, Nimonic, and Rene, including research gaps and future directions for research: 1.

Taguchi's approach is the alternative technique used to devise the experiments.

www.irjmets.com

@International Research Journal of Modernization in Engineering, Technology and Science

[483]

e-ISSN: 2582-5208 International Research Journal of Modernization in Engineering Technology and Science Volume:03/Issue:03/March-2021 2.

3.

4.

5.

Impact Factor- 5.354

www.irjmets.com

Significant grain refining as a thermo-mechanical effect of EDM operation was seen on the machined surface of Inconel 825, 718, and 625. Dislocation density and Micro-strain have also increased because of grain refining. However, grain growth was observed on the Inconel 601 machined work surface. Different tests for Inconel are analyzed, such as Fatigue testing, Surface Roughness, and its Examination, MRR, TWR, EDS analysis, XRD analysis, and VMRR to give a broader perspective of alloys.

A comprehensive review of experimental data draws the effects that WEDM variable parameters have on the output characteristics of the Nimonic C-263 superalloy. The thesis of Nimonic 75, 80A, 90, and the effects of WEDM variable parameters on performance characteristics of the Nimonic C-263 superalloy are derived from the thorough review of experimental data. SEM, XRD, and EDS are various methods used for surface integrity analysis.

The surface structure of the RENE 80 nickel superalloy has white-layers, debris, cracks, voids, and appendages. The EDM climate also has adequate oxidation tolerance. As a result, there is a distinction to be made between machined and unmachined surfaces. The impact of process parameters such as peak current, pulse on-time, and pulse off-time on MRR, SR, WLT, and SCD in the RENE80 EDM. There are hardly any researches that have been conducted on the EDM of Waspaloy alloys and this review paper depicts the research gap on this topic which provides the future scope of machining Waspaloy.

VII. REFERENCES [1]

Ziegel ER, Ross P. Taguchi Techniques for Quality Engineering. Technometrics 1997;39:109. https://doi.org/10.2307/1270793.

[2]

Uyyala SB. An hybrid approach for multi-response optimization of rotary electrical discharge machining of nickel super alloy. Mater Today Proc 2020;23:626–31. https://doi.org/10.1016/j.matpr.2019.05.431.

[3]

Kuş A, Motorcu AR. Nikel esasli waspaloy alaşiminin tel erozyon yöntemiyle işlenmesinde Taguchi metodu ile yüzey pürüzlülüǧü için optimum kesme parametrelerinin tahmini. J Fac Eng Archit Gazi Univ 2017;32:217–26. https://doi.org/10.17341/gazimmfd.300611.

[4]

Hewidy MS, El-Taweel TA, El-Safty MF. Modelling the machining parameters of wire electrical discharge machining of Inconel 601 using RSM. J Mater Process Technol 2005;169:328–36. https://doi.org/10.1016/j.jmatprotec.2005.04.078.

[5]

Kumar S, Dhingra AK, Kumar S. Parametric optimization of powder mixed electrical discharge machining for nickel-based superalloy inconel-800 using response surface methodology. Mech Adv Mater Mod Process 2017;3. https://doi.org/10.1186/s40759-017-0022-4.

[6]

Bisaria H, Shandilya P. Experimental investigation on wire electric discharge machining (WEDM) of Nimonic C-263 superalloy.

Mater Manuf Process 2019;34:83–92. https://doi.org/10.1080/10426914.2018.1532589.

[7]

Goswami A, Technology JK-S and, Journal an I, 2014 undefined. Optimization in wire-cut EDM of Nimonic-80A using Taguchi’s approach and utility concept. Elsevier n.d.

[8]

Sonawane S, university-Engineering MK of king saud, 2018 undefined. Optimization of machining parameters of WEDM for Nimonic-75 alloy using principal component analysis integrated with Taguchi method. Elsevier n.d.

[9]

Mandal A, Das AK. Modeling and Optimization of Machining Nimonic C-263 Super Alloy Using Multi-Cut Strategy in WEDM Laser Surface Modification of SAE8620 HVD Material for Transmission Gear View project Development of a New Strategy to Enhance Cylindrical Wire Electrical Discharge Turning Process View project. Taylor Fr 2016;31:860–8. https://doi.org/10.1080/10426914.2015.1048462.

[10]

Balraj US, Kumar A. Experimental investigation on electrical discharge machining of RENE80 nickel super alloy. Int J Mach Mach Mater 2016;18:99–119. https://doi.org/10.1504/IJMMM.2016.075471.

[11]

Kapoor J, Singh S, Khamba JS. Proceedings of the Institution of Mechanical Engineers , Part B : Journal of Engineering Manufacture 2012. https://doi.org/10.1177/0954405412460354.

[12]

Huda Z, Huda Z. Nontraditional https://doi.org/10.1201/b22393-16.

www.irjmets.com

Machining

Processes.

Manufacturing

2019:271–89.

@International Research Journal of Modernization in Engineering, Technology and Science

[484]

e-ISSN: 2582-5208 International Research Journal of Modernization in Engineering Technology and Science Volume:03/Issue:03/March-2021

Impact Factor- 5.354

www.irjmets.com

[13]

Kalpajian S, Schmid SR. Material removal processes: abrasive, chemical, electrical and high-energy beam. Manufacturing processes for engineering materials 2003:541.

[14]

Dauw D, annals LA-C, 1992 undefined. About the evolution of wire tool performance in wire EDM. Elsevier n.d.

[15]

Aoyama S, Tamura K, Sato T, Kimura T, Sawahata K, Nagai T. High-performance coated wire electrodes for high-speed cutting and accurate machining. Hitachi Cable Rev 1999;18:75–80.

[16]

S. A. Development of high performance wire electrode for wire electric discharge machining. J Japan Soc Electr Mach Engrs 2001.

[17]

Kern R. EDM wire selection. EDM Today 2008:12–6.

[18]

Prohaszka J, Mamalis AG, Vaxevanidis NM. The effect of electrode material on machinability in wire electro-discharge machining. J Mater Process Technol 1997;69:233–7. https://doi.org/10.1016/S09240136(97)00024-1.

[19]

Kern R. Improving wire EDM productivity. EDM Today 2007:10–4.

[20]

Kuriakose S, Letters MS-M, 2004 undefined. Characteristics of wire-electro discharge machined Ti6Al4V surface. Elsevier n.d.

[21]

Muthuramalingam T, Mohan B. Influence of tool electrode properties on machinability in spark erosion machining. Mater Manuf Process 2013;28:939–43. https://doi.org/10.1080/10426914.2013.763973.

[22]

Kapoor J, Singh S, Khamba JS. Recent developments in wire electrodes for high performance WEDM. vol.

2. 2010.

[23]

Jeelani S, Collins MR. Effect of electric discharge machining on the fatigue life of Inconel 718. Int J Fatigue 1988;10:121–5. https://doi.org/10.1016/0142-1123(88)90040-0.

[24]

Rahul, Datta S, Biswal BB, Mahapatra SS. Machinability analysis of Inconel 601, 625, 718 and 825 during electro-discharge machining: On evaluation of optimal parameters setting. Meas J Int Meas Confed 2019;137:382–400. https://doi.org/10.1016/j.measurement.2019.01.065.

[25]

Kumar A, Abhishek K, Vivekananda K, Maity K. Effect of wire electrode materials on die-corner accuracy for Wire Electrical Discharge Machining (WEDM) of Inconel 718. Mater Today Proc 2018;5:12641–8. https://doi.org/10.1016/j.matpr.2018.02.247.

[26]

Pant P, Bharti PS. Electrical Discharge Machining (EDM) of nickel-based nimonic alloys: A review. Mater Today Proc 2019;25:765–72. https://doi.org/10.1016/j.matpr.2019.09.007.

[27]

Choudhary R, Gupta V, Batra Y, Proceedings AS-MT, 2015 undefined. Performance and surface integrity of Nimonic75 alloy machined by electrical discharge machining. Elsevier n.d.

[28]

Pandey AK, Gautam GD. Grey relational analysis-based genetic algorithm optimization of electrical discharge drilling of Nimonic-90 superalloy. J Brazilian Soc Mech Sci Eng 2018;40. https://doi.org/10.1007/s40430-018-1045-4.

[29]

Goswami A, Technology JK-S and, Journal an I, 2017 undefined. Trim cut machining and surface integrity analysis of Nimonic 80A alloy using wire cut EDM. Elsevier n.d.

[30]

Unune DR, Marani Barzani M, Mohite SS, Mali HS. Fuzzy logic-based model for predicting material removal rate and average surface roughness of machined Nimonic 80A using abrasive-mixed electrodischarge diamond surface grinding.

Neural Comput Appl 2018;29:647–62. https://doi.org/10.1007/s00521-016-2581-4.

[31]

Jangra K, Kumar V, Science VK-PM, 2014 undefined. An experimental and comparative study on rough and trim cutting operation in WEDM of hard to machine materials. Elsevier n.d.

[32]

Rajendra Unune D, Pratap Singh V, Singh Mali H. Materials and Manufacturing Processes Experimental Investigations of Abrasive Mixed Electro Discharge Diamond Grinding of Nimonic 80A Experimental Investigations of Abrasive Mixed Electro Discharge Diamond Grinding of Nimonic 80A. Taylor Fr 2015;31:1718–23. https://doi.org/10.1080/10426914.2015.1090598.

www.irjmets.com

@International Research Journal of Modernization in Engineering, Technology and Science

[485]

e-ISSN: 2582-5208 International Research Journal of Modernization in Engineering Technology and Science Volume:03/Issue:03/March-2021

Impact Factor- 5.354

www.irjmets.com

[33]

Xess PA, Biswas S, Masanta M. Optimization of the EDM parameters on machining TI-6AL-4V alloy with multiple quality characteristics.

Appl Mech Mater 2014;619:89–93. https://doi.org/10.4028/www.scientific.net/AMM.619.89.

[34]

Bhattacharyya B, Gangopadhyay S, Sarkar BR. Modelling and analysis of EDMED job surface integrity. J Mater Process Technol 2007;189:169–77. https://doi.org/10.1016/j.jmatprotec.2007.01.018.

www.irjmets.com

@International Research Journal of Modernization in Engineering, Technology and Science

[486]