Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Department of Manufacturing Engineering

Nimonic C263, a nickel-based superalloy, finds extensive application in manufacturing of complex parts in gas turbine, aircraft and automotive industries exclusively for exhaust sections. Machining of the alloy through traditional approach is a difficult task owing to its poor thermal conductivity, work hardening and high strength properties. However, the superalloy can be machined up to desired accuracy by non-traditional machining processes like electrical discharge machining (EDM). Yet again, machining of these difficult-to-machine materials not only consumes a significant amount of energy, but also produces unpleasant noise, hindering the sustainable aspect of the process. To meet the requisite of sustainable EDM and explore the machinability, an experimental investigation is proposed in this work, when Nimonic C263 superalloy is machined with three different electrodes, viz. copper, tungsten, and copper–tungsten. Outcomes of important process parameters, viz. voltage (U), discharge current (I), pulse-on-time (Ton), duty factor (τ), and electrode material, are studied on the responses, viz. specific energy consumption, machining noise (N), material removal rate, electrode wear rate, surface roughness (Ra) and radial overcut (C). Analysis of variance is conducted to analyse the influence of each parameter on the responses. A scanning electron microscope investigation is carried out to analyse the pre-machining and post-machining scenarios on the machined surface. The multiple responses are converted into single response by calculating the net outranking flow by application of preference ranking organization method for enrichment evaluation (PROMETHEE) approach. The PROMITHEE-based results are further improved by using a hybrid cuckoo search algorithm (combined PROMITHEE-based cuckoo search). A confirmative test is further conducted on the optimum machining conditions obtained by the hybrid approach (combination of PROMITHEE and cuckoo search) indicating an overall improvement of 6.02% for the responses, validating the proposed work. © 2021, King Fahd University of Petroleum & Minerals.

World University root node

School of Mechanical Engineering

Vellore Campus

Arabian Journal for Science and Engineering

Sustainable Electrical Discharge Machining of Nimonic C263 Superalloy

The research in eco-friendly and sustainable materials for packaging applications with enhanced barrier, thermo-mechanical, rheological and anti-bacterial properties has accelerated in the last decade. Last decade has witnessed immense interest in employing nanocellulose (NC) as a sustainable and biodegradable alternative to the current synthetic packaging barrier films. This review article gathers the research information on NC as a choice for food packaging material. It reviews on the employment of NC and its various forms including its chemico-physical treatments into bio/polymers and its impact on the performance of nanocomposites for food packaging application. The review reveals the fact that the research trends towards NC based materials are quite promising for Active Packaging (AP) applications, including the Controlled Release Packaging (CRP) and Responsive Packaging (RP). Finally, it summarizes with the challenges of sustainable packaging, gray areas that need an improvement/focus in order to commercially exploit this wonderful material for packaging application. © 2020 Elsevier Ltd

Fulltext

Carbohydrate Polymers

Nanocellulose in food packaging: A review

Al‐Mg‐based composite is used in producing a variety of components. To improve the machinability of the composite, MoS2 is added. For characterizing the machining of the Al‐Mg‐based composite, different wt.% (2, 4, and 6) of MoS2 are added as reinforcement. Wire Electrical Discharge Machining (WEDM) process is performed to analyze the kerf width and surface roughness. Due to the complex nature of the WEDM process, the necessity for its optimization through the use of innovative methods is well‐proven in the process of research. Evolutionary al-gorithms, specifically genetic algorithm based on NSGA‐II and Multiple Objective Particle Swarm Optimization (MOPSO), are used for optimizing kerf width and surface roughness. For assessing the impact of current, pulse on time, and gap voltage on kerf width and surface roughness, an analysis of the selected WEDM process parameters is performed. MOPSO takes lesser iterations as compared to NSGA‐II in giving nearly the same optimal fronts for achieving low kerf width and surface roughness. The 10–12 A of current, 50–57 μs of pulse on time, and 30–33 V of gap voltage are used for the WEDM process based on the Pareto‐optimal solutions and better performance is achieved on the samples. In addition, the supplementary DOE method is applied to determine the relationship between factors affecting a process and the response. The analysis revealed that current has played a major part in the governance of kerf width and surface roughness over pulse on time and gap voltage for Al‐Mg‐MoS2 composite. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

Processes

Parametric study of wire‐edm process in al‐mg‐mos2 composite using nsga‐ii and mopso algorithms

Naturally derived nanocellulose (NC) is a renewable, biodegradable nanomaterial with high strength, low density, high surface area, and tunable surface chemistry, which allows its interaction with other polymers and nanomaterials in a controlled manner. In recent years, NC aerogel has gathered a lot of attention due to environmental concerns. This review presents recent developments of NC-based aerogels and their controlled interactions with other polymers and nanomaterials for thermal applications that include electronic devices, the apparel industry, superinsulating materials, and flame-retardant smart building materials. After going through the distinctive properties of NC aerogels, they are orderly categorized and discussed as thermally insulated, thermally conductive, and flame-retardant materials. ©

ACS Nano

Recent Developments in Nanocellulose-Based Aerogels in Thermal Applications: A Review

The present research aims to develop high strength Al7075–SiC nanocomposites by integration of stir casting and cryo-FSP. Al7075 alloy based nanocomposites reinforced with varying wt.% (2%, 3% and 5%) of nanosize SiC particles were produced through the bottom pouring stir casting technique. The cryo-FSP was successfully carried out using optimized parameters (i.e. 1025 rpm and 65 mm/min traverse speed) on as-cast samples. To understand the fundamentals of the deformation characteristics and microstructural evolution, a systematic study on microstructural evolution has been performed by SEM with EBSD and TEM. The mechanical properties were evaluated by Vickers hardness and tensile testing. Improvement in the mechanical properties is found to be the maximum for the Al7075-3 wt% SiC nanocomposite sample obtained through cryo-FSP (TS = 552 MPa, and %El. = 17%) as compared to other samples studied (Al7075 alloy/composites). Secondary processing through cryo-FSP not only refined the matrix grain size to 1–3 μm range, but also suppressed the coarsening of the strengthening η′ phase due to higher cooling rate. Moreover, the reinforced nanosize SiC particles distributed uniformly within the matrix thereby enhancing the particle/matrix interface characteristics. These modifications in microstructure drastically enhance the strength (YS, hardness) and ductility of the material simultaneously. The detailed strengthening mechanisms have been analyzed and correlated with the mechanical properties. © 2020 Elsevier B.V.

Journal of Alloys and Compounds

Effects of cryo-FSP on metallurgical and mechanical properties of stir cast Al7075–SiC nanocomposites

This study intended to optimize the process parameters of the friction stir welding (FSW) technique to maximize the mechanical properties of the AA6082/B4C composite weldments. The metal matrix composites are prepared with aluminum alloy 6082 and boron carbide particles of 10µm size by using a stir casting technique. The central composite design technique is applied to design the FSW experiments. The experiments were carried out in butt joint configuration by varying welding transverse speed, axial load, plunge depth, and tool rotational speed. The optimum parameters are estimated by considering output responses such as ultimate tensile strength and microhardness. The effect of process parameters on output responses was analyzed graphically. Two optimization techniques, namely genetic algorithm and desirability function approach, are implemented to identify the optimal values of process parameters. The results obtained by both optimization techniques are in good agreement. The optimum values are validated with experimental results. © 2021, ASM International.

Department of Design and Automation

Journal of Materials Engineering and Performance

Multi-Performance Optimization in Friction Stir Welding of AA6082/B4C Using Genetic Algorithm and Desirability Function Approach for Aircraft Wing Structures

The conventional constant current arc welding of Hastelloy X (Ni-Cr-Fe-Mo) leads to the solidification and liquation cracks in the weldment. The higher heat supplied in constant current weldment develops the secondary carbide precipitates. It promotes the development of hot cracks in the weldment. In this study, joining of Hastelloy X plates was carried out by constant current gas tungsten arc welding (GTAW) and pulsed current gas tungsten arc welding (PCGTAW) with C263 filler wire. The result discovered that no hot cracks were formed in the weldment. In constant current mode, Cr-rich and Mo-rich Cr23C6 (M23C6), Fe2MoC, Fe3Mo3C (M6C), and Cr2Ti precipitates were observed. Whereas, in pulsed current mode, Ni3(Al, Ti), Ni3Ti, Co3Ti, Cr2Ti precipitates are found due to the segregation of Co, Al, and Ti. No Cr-rich and Mo-rich carbide phases identified in pulsed current weldment due to rapid cooling rate and higher thermal gradient observed during solidification. The tensile results revealed that 8.23% increase in the ultimate tensile strength and a 29.62% increase in elongation of pulsed current mode welding compared to constant current welding. Further, the microhardness and impact toughness of PCGTAW is 3.32% and 5.45% higher than GTAW, respectively. In pulsed current welding, better mechanical properties were identified compared to constant current welding. The nonappearance of Cr and Mo-rich phases and refined microstructure in the weldment are the main reason for better strength. © IMechE 2021.

Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering

Prospects of pulsed current arc welding on aerospace grade Hastelloy X

The role of surface roughness is very important in machining processes. The surface finish and tolerances are most critical quality measures in various mechanical products. The main objective of this paper is to find out the effect of machining parameters on a surface roughness in a lathe boring operation in dry condition. This paper shows the study of surface roughness for boring of gray cast iron (250BHN) by using carbide tool under dry condition. The effect of boring parameters (tool nose radius, feed, spindle speed and depth of cut) was analyzed using analysis of variance. These variables were computed using Taguchi’s design of experiments (DOE). The DOE gives the optimal values of speed, feed and depth of cut for tool nose radius of 0.4 and 0.8 mm. The three-factor three-level fractional experiments were conducted. This result shows that the effects of speed, feed, depth of cut and tool nose radius on surface finish are statistically significant. The results observed that using larger tool nose radius always gives a good surface finish. The results also revealed that the following level for each of the factors produces the smooth surface finish within the range of experiments: larger tool nose radius, lower feed, higher speed and lower depth of cut. © 2021, The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

Lecture Notes in Mechanical Engineering

Parametric Evaluation of Lathe Boring Operation to Improve the Surface Finish of Gray Cast Iron (SG-260) Under Dry Condition

The technological challenges faced by any industry in machining OHNS steel in the use of tools and die by conventional processing techniques point to tool wear rate and poor surface finish. To overcome these, Electrical Discharge Machine (EDM) process, an inevitable Unconventional Machining process is used in the precision and micro component manufacturing industries. Here an attempt has been made to machine OHNS material with a lately developed copper titanium diboride (Cu-TiB2) of 16% wt of TiB2 is prepared through powder metallurgy route which enhances the shortcomings obtained in conventional techniques. The experiment models are made to optimize through statistical Response Surface Methodology (RSM). The experiments were conducted by considering the effect of pulsating direct current, pulse time ON, and pressure flushing. Then, ANOVA is executed to predict the impact of each parameter and its significance concerning the output responses of roughness (SR) and Volume of Material removed (MRR). The equation developed for each output response and then the optimum process parameters obtained in the desirability based multi-objective optimization using RSM. The minimum surface roughness and maximum material removal rates are attained at 14 A, 16(μs) and 0.6 MPa. Then the confirmation experiments were carried to validate the model and it is witnessed that the error percentage attained was within the satisfactory range. © Published under licence by IOP Publishing Ltd.

IOP Conference Series: Materials Science and Engineering

Effect of Titanium Di-Boride/Copper (TiB2-Cu) Electrode on the Machinability of OHNS Steel by EDM Process

Globe valves are primarily manufactured by a casting process are extensively used for controlling the fluid flow in pipelines in various mechanical devices, viz. boilers, condensers, overhead tanks, etc. However, the component faces a lot rejection due to various casting defects occurring during the manufacturing process majorly because of the improper gating system design. In view of this, the present work proposes a numerical simulation on globe valves prepared by the sand casting process by varying the number of gates in gating system design. The effectiveness of both the designs is evaluated in terms of flow front, air entrapment and porosity percentages obtained from both the designs. From the simulation results, it is observed that an increasing number of gates in gating system design can result in better flow front, lesser air entrapment, promotion of directional solidification and lesser porosity percentage in casted product. The proposed model can be useful for producing sound casted product and defect-free casting thereby reducing the manufacturing costs. © 2021, Springer Nature Singapore Pte Ltd.