Narendranath .S

National Institute of Technology Karnataka | NITK Surathkal · Department of Mechanical Engineering

Conventional machining techniques face challenges in processing Ni-Ti-Hf alloys, which exhibit superior properties and are increasingly considered promising materials for high-temperature shape memory actuator applications. Thus, this article focuses on investigating the effect of Wire Electric Discharge Machining (WEDM) input parameters, namely di...

Production of dissimilar weldments using microwave hybrid heating is currently gaining immense impetus in the field of advanced welding. This is because such heat source could provide benefits like cost-effectiveness, rapid, volumetric, uniform and selective heating, and efficient throughput which would be significant to various industries. Till-da...

Ni-Ti-Hf Shape memory alloys (SMAs) have shown promising results in high-temperature applications in aviation, space and energy exploration, actuators, etc. In the past decade, extensive work has been carried out to understand the behavior of High-Temperature SMAs (HTSMAs). NiTi-based SMAs are grouped as hard-to-machine materials, and machining the...

Shape memory alloys (SMAs) have the unique ability to regain their shape under specified conditions, making them extremely useful for a wide range of applications. However, non-traditional machining techniques could be more effective for high-temperature SMAs as they provide better shape recovery properties than conventional methods, necessitating...

Lightweight materials with high strength and ductility have immense potential in revolutionizing the automobile, aerospace, bio-medical and defence sector. Magnesium and its alloys are the candidates that are best suited for application in above mentioned sectors. However, achieving combination of properties such as high strength, good ductility an...

In the present study, taper cutting is performed with the aid of a uniquely designed fixture. This is attempted to avoid the difficulties in tapering using wire electric discharge machining like wire break, dimensional error, guide wear, non-uniform flushing and low surface quality. An investigation of output parameters was made during taper machin...

Due to extensive mechanical load bearing capability under high temperature and pressure, Nickel based super alloys are widely incorporated in aerospace and aviation industries in various sections like chemical, fuselage, engine, combustor components, etc. Hastelloy-X is a Ni-based super alloy consisting mainly Ni, Cr, Fe, Mo and Co, which has good...

The investigation on material removal by thermal erosion of discrete spark and vaporization in wire electrical discharge turning process was made to understand the crater size variation on turned components. In this study the modelling is done to establish the relationship between dependent and independent variables through Buckingham’s Pi-theorem,...

Fabrication of shape memory alloys using wire electro discharge machining (WEDM) has gained popularity over the last few years. Most widely used machining parameters of WEDM process are pulse on time (Øon), pulse off time (Øoff), servo voltage (σ) and wire feed (ω). WEDM responses like material removal rate (MR), surface roughness (SR), kerf width...

The Altemp HX is a nickel-based superalloy having many applications in chemical, nuclear, aerospace, and marine industries. Machining such superalloys is challenging as it may cause both tool and surface damage. WEDM, a non-contact machining technique, can be employed in the machining of such alloys. In the present study, different input parameters...

Wire electric discharge machining (WEDM) is nonconventional machining that provides machining solutions irrespective of the material hardness. In the present study, a simple profile was machined on Microfer 4722 at different slant angles using to know the effect of machining parameters. A unique method of obtaining taper components was employed by...

Inconel-HX is a superalloy possessing high mechanical properties and excellent high-temperature strength. Wire electric discharge machining a nontraditional machining technique gives high accuracy for machining such hard materials. In the current investigation, the influence of different machining parameters like wire feed, pulse-off time, servo vo...

Titanium alloys, in particularly Ti-6Al-4V alloy is used enormously in many high-tech sectors specially in aerospace industries due to its superior properties. Machining process (for example wire electrical discharge machining) to reshape this alloy affects the integrity of the newly generated surfaces. This experimental study has identified three...

Hastelloy-X is one of the wrought nickel-base superalloy comprising of oxidation resistance and high-temperature strength. Wire electric discharge machining process is the favoured technique for precise component fabrication of such materials. Apart from precision the most essential aspect with surface integrity and cutting velocity in manufacturin...

The oblique/tapered form of precise components has many applications like dies, nozzles, inserts, cutting tools, and other components. Wire electric discharge machining is an erosion technique that helps in precise machining of hard materials. In the present study, basic profiles were machined using a novel slant-type fixture to achieve a slant sur...

The mechanical integrity of rolled ZM21 Mg was improved by equal channel angular pressing (ECAP) to function as a potential biodegradable bone screw implant. Electron backscattered diffraction (EBSD) revealed deformed grains of 45 µm observed in rolled ZM21 Mg. They were transformed to equiaxed fine grains of 5.4 µm after 4 th pass ECAP. The yield...

Alloy-706 is a newly introduced exceptional class of turbine wheel alloy for high-performance aero-engine. To precisely measure the WEDM performance of complex aero-engine parts, the RSM-based TLBO algorithm is proposed in the current study. Morphology, topography, recast layer thickness, and roughness parameters of machined surface are studied...

The present study aims to precisely manufacture the turbine wheel slot using a novel trim-offset approach of wire-electrical-discharge-machining (WEDM) in order to overcome the challenges of a conventional broaching process. Two dimensional model of turbine wheel slot is prepared in ‘ELCAM’ software to generate the computer-numerical-control (CNC)...

Wire electric discharge machining non-contact machining process based on spark erosion technique. It can machine difficult-to-cut materials with excellent precision. In this paper Alloy-X, a nickel-based superalloy was machined at different machining parameters. Input parameters like pulse on time, pulse off time, servo voltage and wire feed were e...

Hastelloy-X a nickel-based alloy used in nozzles, flame holders, turbine blades, turbocharges, jet engine tailpipes, afterburner components etc. having complex tapering profiles. Wire electric discharge machining proves to be the most beneficial machining technique as it provides required accuracy for the components. In the present research, a slan...

Response surface methodology (RSM) is used for mathematical modeling of friction stir welding parameters for joining AA6061 composite material. Characteristics of joints were examined through response characteristics such as ultimate tensile strength (UTS) and microhardness (Hv) using RSM. Microstructure examination was carried out using optical mi...

In this study, AZ80/91 Mg alloys were used to comprehend the electrochemical corrosion behaviour of coarse-grained and fine-grained Mg alloys in different concentration of NaCl solution as well as in the marine environment. The inadequate studies of the corrosion response of ECAPed AZ80 and AZ91 Mg alloy in a different environment were noticed. Acc...

Wire electric discharge machining non-conventional process that removes materials by thermal erosion. Tapering in WEDM has many applications in machining accurate geometric profiles. In the present investigation, a slant type taper machining was performed to produce taper profiles with the help of the slant fixture. The machining parameters such as...

The oblique/tapered machining is a unique method in wire electric discharge machining to get taper profiles difficult to machine materials. These profiles have many applications like dies, nozzles, inserts, cutting tools and other components. In the present study, a simple square profile is machined using a slant type fixture to achieve a tapered p...

Biodegradable magnesium has regained great attention due to its ability to temporarily offer mechanical strength and degrade completely once the injured pathological tissue is healed. A few clinical applications of Mg-based implants were reported in the last century. However, the knowledge and experience is being gained continuously by studying the...

The present study discusses, wire spark discharge machining and optimizations of its process parameters (Voltage (V), pulse off duration (Toff), pulse on duration (Ton), wire-speed (WS) and servo feed (SF)) for machining of Ti50Ni49Co1 and Ti50Ni45Co5 alloys conventionally used bone staple material. These alloys are developed through Vacuum arc mel...

The present study discusses, wire spark discharge machiningWire spark discharge machining and optimizationsOptimization of its process parameters (Voltage (V), pulse off duration (Toff), pulse on duration (Ton), wire-speed (WS) and servo feed (SF)) for machiningMachining of Ti50Ni49Co1 and Ti50Ni45Co5 alloys conventionally used bone staple material...

Magnesium alloys have poor tensile strength, ductility and corrosion resistance properties associated with other engineering materials like aluminum alloys, steels and superalloys etc. Therefore, many researchers worked on equal channel angular pressing of magnesium alloys to improve the mechanical properties and corrosion resistance. In this work,...

The present work describes the evolution of microstructure and enhancement of mechanical properties of friction stir welded AA6061/SiC/FA Hybrid AMCs (HAMCs). Various joints were produced using different traverse speed from 30 mm/min to 80 mm/min. Microstructural analysis was carried out using Optical microscopy and scanning electron microscopy. Me...

Thermal Energy Storage (TES) has gained popularity in recent times as it provides an efficient and economical approach to limit the discrepancy between supply and demand for energy. In the current paper, the thermal performance of a hypereutectic zinc-12% aluminium (ZA 12) alloy has been studied and is proposed as a potential metallic phase change...

Two step equal channel angular pressing carried out on as cast ZE41 Mg alloy resulted in a remarkable grain refinement. As compared to grain size of 46 µm in as cast sample, refinement upto 2.5 µm was achieved after 8th pass equal channel angular pressing (ECAP). The combined effect of crystallographic orientation and grain refinement was investiga...

The use of microwave energy for processing of different materials is gaining significant attention in today’s manufacturing industries. The microwave energy found to be applied in sintering, cladding, brazing, joining, casting and drilling of variety of materials. This paper is focused on the detailed review of the research works carried out on the...

This study considers the effect of wire electro discharge machining (WEDM) parameter peak current (Ip) and pulse peak voltage (Vp) on the machined surface morphology of TiNiCu shape memory alloys. Various defects of machined surfaces were identified and correlated with parameter values and measured average surface roughness (Ra) and average surface...

This work reports the characterization of AA6061/SiC/FA hybrid composites joined using friction stir welding (FSW). FSW was conducted by employing various tool pin profiles such as straight cylindrical (SC), tapered conical, straight square (SS) and cylindrical threaded. Microstructure and mechanical characteristics of joints were investigated usin...

In the present research work, an in-house developed fixture is used to achieve taper profiles which avoids the disadvantages in convention tapering operation in wire electric discharge machining like wire bend, inaccuracies in taper, insufficient flushing, guide wear etc. A simple triangular profile was machined at 0°, 15° and 30° slant/taper angle...

Equal channel angular extrusion, patented in Russia by V. M. Segal in 1977, has become a promising technique to enhance tensile strength and corrosion resistance of Mg alloys. It is believed that the processing temperature ensures the production of ECAE-processed billet without surface defects. Indeed, ECAE processing temperature affects microstruc...

Shape memory alloys are currently replacing many conventional materials due to their various useful properties. Besides shape recovery above austenitic temperature and pseudo-elasticity, high strength and good corrosion properties are one of the many mentionable properties of these alloys. Due to their intriguing properties, aerospace, biomedical a...

Fly ash has been receiving the extensive concentration as a strong reinforcing element for Aluminum Matrix Composites (AMCs) to strengthen the properties and cut the price of manufacturing. AA6061 reinforced with various weight percentages of fly ash particulates and a constant weight percentage of SiC were prepared by stir casting technique as it...

Cryogenic diamond burnishing is an impactful method to enhance the functional performance of the product. In this article, an experimental study on the diamond burnishing of 17-4 precipitation hardenable stainless steel in a cryogenic cooling condition has been presented. This material has excellent corrosion resistance, high strength and enormous...

TiNiCo Shape memory alloy are most usable material in the field of biomedical, aerospace and robotics applications due to their unique class of properties. Super elasticity, shape memory effect and two phase transformation behaviour of these alloys make unique material. Machining of shape memory alloy is quite difficult through traditional machinin...

This study aims to investigate the corrosion behavior of wrought AZ80 magnesium alloys in different chloride ion concentrations and exposure time. During the study, the effect of exposure time and chloride content on the corrosion resistance of AZ80 wrought Mg alloy has been studied with 2, 3.5, and 5 wt% NaCl aqueous solution for 12 h and 24 h exp...

Burnishing is a chipless secondary finishing operation which yields excellent surface finish. The present work focuses on multi-response optimization of diamond burnishing on 17-4 precipitation hardenable stainless steel under dry environment by using Taguchi based grey relation analysis (TGRA) to simultaneously minimize surface roughness and maxim...

In the current work, wrought AZ80 Mg alloys were subjected to equal channel angular pressing (ECAP) followed by hot rolling (HR). Then, combined effects of ECAP and HR on microstructure and electrochemical corrosion behavior were investigated in 3.5wt.% NaCl solution. The microstructure and corrosion morphology study was made through optical and sc...

The galvanic corrosion behavior of as‐received and ECAPed ZE41 Mg alloy coupled with Al7075 alloy is investigated using zero resistance ammeter in three different corrosive environments, 0, 0.1, and 1 M NaCl, to mimic the conditions experienced in engineering applications. The mechanism of galvanic corrosion for the ZE41 Mg–Al7075 aluminum alloy is...

17-4 precipitation-hardenable (PH) stainless steel is one of the widely used materials in various applications of engineering practices owing to their excellent corrosion resistance and high strength. The components such as automotive body, aerospace compressor blades, turbine blades and molds demand higher load carrying capacity and improved fatig...

Wire electric discharge machining (WEDM) is a thermo-electric spark erosion process that can machine any difficult to cut materials. Taper cutting in WEDM is a unique feature that has many problems such as taper angular inaccuracies, wire cut and distribution of dielectric fluid during machining. In the present research work, angular machining is p...

Nickel-based superalloys are classified under difficult to machine materials due to its higher affinity to tool materials and low thermal diffusivity. Wire electric discharge machining (WEDM) is a spark eroding technique for precise machining of such superalloys with complex machining geometries. Tapering in WEDM has many disadvantages like wire br...

In order to study the influence of plastic deformation, annealing and aging treatment on pitting corrosion, the AZ80Mg alloy was subjected to equal-channel angular pressing (ECAP) by route R at 325°C for up to 4 ECAP passes (P) and annealing conditions of 523 K, 623 K and 723 K followed by aging treatment at 6 h and 12 h. A microhardness and corros...

In this study, the effect of dielectric flushing pressure and direction on the machining responses of wire electro discharge machining (WEDM) was investigated. Vacuum-melted titanium–nickel–copper (TiNiCu) shape memory alloy Ti50Ni25Cu25, homogenized at 500°C, was used as the workpiece material. The flushing pressure was varied from 0·5 to 1·5 kg/cm2...

Wire electro-discharge machining (WEDM) is a widely used machining process for machining of difficult to cut materials, which are used in precision profile applications like dies, metal stampings, and gas turbine parts. In the present research work, a new slant type taper fixture was used to obtain angular machining of triangular shape slots of sid...

AZ91 Mg alloys were processed by equal channel angular extrusion (ECAE) up to 4 passes through route-R. The increase in number of ECAE passes to yield fine-grain structure in the bulk Mg alloy with a more dislocation density, this enhances mechanical properties and corrosion resistance. Indeed, microstructural observations revealed an equiaxed and...

Computer Aided Cooling Curve Analysis (CA-CCA) is the utilization of time-temperature graph to reveal several processing and material parameters. Its application ranges from prediction of transition temperatures, amount of different phases, latent heat and dendrite coherency point among various others. In the current paper, both Newtonian and Fouri...

This is copyright for a fixture used to hold the workpiece at a different standard angles like 0, 15, 30, 45, 20, 35, 60 and 75

Secondary finishing operations are the primary requirement of the manufacturing industries to achieve dimensional tolerance of the components. Burnishing is essentially a surface finishing operation usually performed after machining to achieve superfinishing. Diamond burnishing is one of the finest finishing technologies which has been conducted on...

In this article, the effect of channel angles on material properties was investigated during equal channel angular pressing of AZ80 magnesium alloy using processing route R at 325 °C processing temperature. Channel angles of 90° and 110° and common corner angle 30° have been considered for this study. It has been revealed that the channel angle has...

Wire electro-discharge machining is one of the advanced machining processes which can machine all conductive materials without changing their internal properties. Pulse on time and servo voltage are the most influential process parameters of wire electro-discharge machining. In the present study, attempts have been made to study the effects of thes...

The present work attempts to study the parameters influencing wear, namely, applied load, heat-treated temperature, sliding velocity, and sliding distance using statistical Design of Experiments (DOE) and Response Surface Methodology (RSM). The wear behavior of super duplex stainless steel was evaluated under dry sliding conditions. A three-level C...

Wrought magnesium alloys are a potential material for automobile, aerospace, marine and electronics industries because of less density, higher specific strength, damping characteristics and electromagnetic shielding properties. In spite of this interest, Mg alloys have not been extensively utilized owing to their poor mechanical behavior and corros...

In the present study, welding of Inconel-625 through the use of microwave hybrid heating (MHH) has been achieved at two power levels 600 W and 900 W in a low-cost home microwave oven. Nickel-based powder EWAC was used as filler interface between faying surfaces. Effect of power variation on the metallurgical and mechanical characteristics of the mi...

The productivity of the components is adversely affected by the poor surface integrity characteristics as a consequence of the generation of high temperature in the burnishing zone. The abundant use of conventional lubricants causes environmental pollution and health problems. To overcome these issues, cryogenic cooling has been used across the wor...

The aim of this review article is to provide a brief mechanistic overview of magnesium alloys, equal channel angular pressing and corrosion behavior of un-ECAPed and ECAPed Mg alloys. The considerate of the corrosion processes of ECAPed Mg alloys builds upon interpretation of the corrosion of fine-grain magnesium alloys. This provides an understand...

In the present work, aluminum alloy 6061/SiC/fly ash aluminum matrix composites were welded successfully using friction stir welding process. Microstructure of weld joints was examined using optical microscope and scanning electron microscope. Mechanical properties namely, microhardness and ultimate tensile strength of the joints were studied. The...

A major sustainability concern of manufacturing industries is indiscriminate use of lubrication, energy consumption, and allied cost. To avoid such kind of situation and to improve the product quality, sustainable manufacturing concept has been widely used. One of the popular technique is the use of Minimum Quantity Lubrication (MQL) as a working f...

The quality of welded joints developed using microwave hybrid heating (MHH) technique is largely influenced by properties of the constituents employed in the process. This article investigates the influence of process parameters on tensile strength and flexural strength of Inconel-625 plates welded through MHH. Experiments were planned according to...

Diamond burnishing is a cold working process, which produces a work hardened and uniform surface by plastic deformation. The aim of the present work is to study the behavior of diamond burnishing on surface integrity of 17-4 precipitation hardenable stainless steel (PH-SS) under cryogenic, minimum quantity lubrication (MQL) and dry environments. Su...

In this study 6 mm thick plates of aluminum matrix composites (AMCs) composed of AA6061/SiC (10 Wt. %) /fly ash (7.5 Wt. %) were butt welded using friction stir welding (FSW. Microstructural characterization of weld joints was conducted by using optical microscopy (OM) and scanning electron microscopy (SEM). The microstructure of the weld revealed...

In this research work, aluminum matrix composites (AMCs) plates were welded using friction stir welding (FSW). AMCs contain AA 6061 as base metal with SiC and fly ash particles as reinforcements. FSW process parameters considered in this work were tool rotational speed (rpm), tool traverse speed (mm/min) and tool tilt angle (degrees). Taguchi L9 or...

In this study, three distinct TiNiCu alloys were processed using wire electro discharge machining. These alloys are potential materials for smart applications owing to their fast actuation response resulting from suitable martensitic transformation temperatures. Due to differences in their physical property (thermal conductivity in this case), thes...

Diamond burnishing is one of the most popular surface finishing technique used to achieve an excellent surface finish. The aim of the present study is to investigate the effect of process parameters in diamond burnishing of 17-4 PH stainless steel (PH SS) under cryogenic environment. The requirement of a sustainable environment for various machinin...

This paper investigates the effect of homogenization treatment on microstructure, micro-hardness and corrosion behavior of AZ80 wrought Magnesium alloy. Homogenization at 523 K, 623 K, and 723 K were accomplished. Meanwhile samples were cooled in the furnace after 6 h and 12 h of diffusion annealing treatment. In this study, samples were characteri...

This paper presents the use of multilayer perceptron (MLP) for fault diagnosis through a histogram feature extracted from vibration signals of healthy and faulty conditions of single point cutting tools. The features were extracted from the vibration signals, which were acquired while machining with healthy and different worn-out tool conditions. P...

In this paper the finite element simulation approach has been employed for the work that has been recently carried out by Davanageri et al.(2017). The super duplex stainless steel AISI 2507 material was heat treated at 850°C with different ageing time (30, 60, 90 minutes), followed by water quench. The heat treatment was carried out to encourage th...