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

Blending of lamellae grains with other organic elements is the basic feature of biological nacre material to demonstrate its highest strength. Reconstruction of these hierarchical structures with combinations of metallic lamellae grains is a challenge of the day which is trending in the field of bioinspired structural materials. Such nanolaminated aluminum alloy based metallic nanocomposites are processed through addition of graphene using powder metallurgy route followed by hot extrusion. Intervallicre-nucleation to achieve lamellae grains in the nanocomposites by addition of graphene significantly enhanced the mechanical properties like micro-hardness and strength of the prepared nanocomposites. © 2020 Elsevier B.V.

World University root node

School of Mechanical Engineering

Vellore Campus

Materials Letters

Property evaluation of hot extruded aluminum alloy – Graphene nanocomposites

A Study On Shift Towards Digitalization Of Medical Reimbursement By Insurance Companies During COVID Like Pandemic Situation

Hastelloy X develops hot fissuring during fusion welding, which could be precluded using single-pulsed gas metal arc welding (SP-GMAW) and double-pulsed gas metal arc welding (DP-GMAW). The outcome of this research is to provide a better insight into microstructural characteristics, and mechanical properties of Hastelloy X welded by GMAW, SP-GMAW, and DP-GMAW techniques. GMAW depicts the cellular dendrites, whereas DP-GMAW and SP-GMAW displayed fine equiaxed dendrites. Mo-rich segregation is identified in the interdendritic region of GMAW owing to high solidification time. Mo-rich segregation is reduced for SP-GMAW, whereas it is completely precluded for DP-GMAW due to the existence of refined grain. The development of M3C (Fe2MoC) and M6C (Fe2Mo4C) carbide precipitates is identified in GMAW and SP-GMAW. But, DP-GMAW displays the absence of Mo-rich carbides and the development of Mo1Ni4 intermetallic precipitates. DP-GMAW provides better joint efficiency (96.32%), UTS, and ductility, which is followed by SP-GMAW and GMAW. DP-GMAW shows higher mean microhardness (7.31% and 3.52%) and impact toughness (49.01% and 26.67%) on comparison with GMAW and SP-GMAW, respectively. Inverse pole figure (IPF) maps of SP-GMAW weldment confirmed that the broad and straight dendrites formed tend to grow along &lt; 100 &gt; direction during the entire solidification process. DP-GMAW also displays the major intensity shift from &lt; 100 &gt; to &lt; 111 &gt; direction. Evidence for the formation of equiaxed grains of random orientation along with dendrites is confirmed by IPF maps from DP-GMAW weldments. The presence of these equiaxed grains in the DP-GMAW weldment might have contributed to the enhancement of tensile properties. © 2021, ASM International.

Department of Design and Automation

Journal of Materials Engineering and Performance

Investigation of Double-Pulsed Gas Metal Arc Welding Technique to Preclude Carbide Precipitates in Aerospace Grade Hastelloy X

In this manuscript, the latest developments pertaining to sensitization are discussed. Sensitization leads to intergranular corrosion and intergranular stress corrosion cracking. The advantages and disadvantages of conventional methods to combat sensitization are elaborated. Emerging/newer techniques such as grain boundary engineering, creation of orientation gradients, and high density of twinning to improve resistance to sensitization are also covered. Detection and monitoring of deleterious phase precipitation such as carbides, nitrides, and other intermetallic phases during operation necessitate making use of nondestructive testing (NDT) methods. Possible information that we get from NDT is for material characterization includes the size, shape, and location of a defect. Herein, the significant developments for monitoring and detection of phases concerning sensitization by NDT are discussed. These range from magnetic methods to ultrasonic techniques. The multi-physics approach is essential to fully utilize NDT to ensure/predict the lifetime of the components used in the industry. Further, proper selection of suitable NDT for defect detection can avert accidents, catastrophic failures, and economic losses due to corrosion degradation. For this, the corrosion engineer/corrosionist properly apply the suitable techniques (prevention, monitoring, and assessment) to address the issues of sensitization among the wide choice available. © 2021, ASM International.

Metallography, Microstructure, and Analysis

Sensitization of Austenitic Stainless Steels: Current Developments, Trends, and Future Directions

The driver’s comfort and position are factors of utmost importance in motorsports, and these are key aspects in deciding the overall performance of a race car. This paper presents a strategy to increase overall driver comfort in a race car by providing design proposals for a comfortable seat. A prototype was built, as per norms and cockpit constraints, from which the design considerations for the driver’s position were decided. Vertebral and thigh impressions of four drivers were taken by using expandable two-part urethane foam. Three-dimensional scanning technique was used to convert these impressions into point cloud data. The data were refined to form surfaces of respective impressions. These scanned surfaces were converged to a single optimized seat design which was comfortable for all drivers. Using data acquisition (DAQ), a comparative study of lap timings was done on the experimental seat and existing seat design for validation. This methodology of seat design was implemented to improve driver performance. It was observed that from a graphical comparison of car’s timings on both seats, the timings of the car with existing seat design showed a steeper increase in timings than the car with new seating design. © 2021, Springer Nature Singapore Pte Ltd.

Lecture Notes in Mechanical Engineering

Design Analysis and Fabrication of Race Car Seat to Increase Driver Comfort

Nickel-based alloys like Inconel 718 occupy a large share in the aerospace industry because of superior mechanical properties. However, Inconel 718 is categorized as a difficult to machine material. Ultrasonic assisted grinding (UAG), a hybrid grinding process has captured the attention of researchers for grinding of Inconel 718 due its inherent capability in overcoming several problems associated with processing difficult to grind (DTG) materials. Lubrication machining is used for hard to machine materials and minimum quantity lubrication (MQL) is a sustainable method employed to overcome machining problems in such materials. In this context, this work aims to examine UAG of Inconel 718 under different lubrication conditions. Optimization of UAG is necessary in identifying the best parameter combination depending on the process capability of a given machine tool. For this, experimentation using Taguchi L18 orthogonal array parameter design and optimization based on Grey Relational Analysis (GRA) have been performed. The optimization has been performed using grinding forces (tangential force, Ft) and average roughness parameter (Ra) as the output parameters. Additionally, regression models have been developed to enable the prediction of response variables. To determine the factor contribution on output response ANOVA table and S N ratio analysis have been performed on the Grey Relational Grade (GRG). The statistical analysis has revealed feed has the maximum impact on Ra and cutting velocity has the least effect. Similarly, for Ft depth of cut has the maximum effect and cutting velocity has minimum effect. Confirmation experiments reveal that the regression models were able to make accurate predictions under the test conditions. © 2021 Author(s).

AIP Conference Proceedings

Optimisation of ultrasonic assisted grinding of inconel 718 using grey relational analysis

In this study, an attempt has been made in PMEDM process to sustain the homogeneity in the powder-dielectric mixture irrespective of the nature of the powders, their particle size, concentration etc., The traditional way of powder mixing system in Powder Mixing Electric Discharge Machining (PMEDM) has been refurbished with a novel Eductor based system along with a metering devise to ensure uniform mixing of the powers with the dielectric. Additionally sintered crucible filtration test on the sample of powder-dielectric mixture ensured the presence of known quantity of powders in the dielectric. The experiments are conducted on Titanium alloy with Gap current, Duty factor, Delivery pressure, powder types (Alumina, Silica, and copper) and concentration of these powders as variable process parameters. The output responses, namely material removal rate, tool wear index and surface finish obtained during the machining process have been optimized using AHP-TOPSIS method. The confirmation test indicated that the closeness co-efficient value for the TOPSIS analysis improved by 2.37% compared with the predicted value. © 2021, The Author(s).

Fulltext

SN Applied Sciences

Enhancement of machinability of titanium alloy in the Eductor based PMEDM process

The microstructure and mechanical behavior of the Gas Tungsten Arc (GTA) welded joint of ferritic/martensitic (F/M) P91 and austenitic SS304L steel was investigated in as-welded and post-weld heat treatment (PWHT) conditions. The microstructural studies included the particle size and its distribution, grain size, and percentage area fraction of the precipitates (%AFP) in different zones of the weldments. In as-welded condition, weld metal showed untempered martensitic microstructure devoid of carbide precipitates. After the PWHT, weld metal was characterized by tempered martensitic microstructure along with the decoration of the coarse carbide particles at PAGBs and fine carbonitride particles inside the matrix region. The mechanical behavior of the dissimilar weld was analyzed in as-welded and PWHT conditions by performing tensile testing, Charpy impact testing, and microhardness testing. A significant variation in microstructure and mechanical properties was obtained across the dissimilar welded joint (DWJ) for as-welded, which was minimized after the PWHT. The minimum%AFP in the coarse grain heat-affected zone was measured due to the formation of the precipitate-free soft δ ferrite patches, which also showed a negligible response to PWHT. The poor Charpy impact toughness (CIT) of 0.8 ± 1.5 J and high tensile strength of 864 ± 12.5 MPa were measured for the as-welded joint. The combination of high strength and low CIT was obtained mainly due to the untempered martensitic microstructure in the weld fusion zone. The DWJ after the PWHT showed a significant increase in Charpy impact toughness (CIT), and it was measured 70 ± 4 J. Improved mechanical behavior with a good combination of ultimate tensile strength and CIT were obtained after the PWHT. © 2021 Elsevier B.V.

Fusion Engineering and Design

Role of the heterogeneity in microstructure on the mechanical performance of the Autogenous Gas Tungsten Arc (GTA) welded dissimilar joint of F/M P91 and SS304L steel

This work reports one-step synthesis process of LiOH-castor oil based polyurethane foam (PU) by completely replacing synthetic polyol. The reaction involved reacting varying weight percentage of lithium hydroxide with castor oil along with isocyanate. The successfully synthesized stable PU foams were characterized for density, sol fraction, cellular morphology, polymer phase morphologies and thermo-mechanical properties. The properties of the LiOH-castor oil based PU foams were compared with the conventional PU foam. Flexibility of the synthesized foams was observed to be lower than conventional PU foam for 0.05%, 0.1% and 0.5% LiOH due to the presence of closed cells with pin holes. Whereas, presence of open cellular structure in 0.3% LiOH-castor oil based PU foams showed flexible nature. Sol fraction of all the synthesized foams was found low (~ 5%) indicating improved reactivity. Thermal conductivity, glass transition temperature, thermal stability and mechanical properties of the synthesized PU foams suggest the possibility of replacing conventional PU foams for various applications. © 2021, The Polymer Society, Taipei.

Department of Chemical Engineering

School of Chemical Engineering

Journal of Polymer Research

One-step synthesis and characteristics of LiOH-castor oil based stable polyurethane foam

The authors regret “The experimental set up shown in Fig. 1 is wrongly provided in the manuscript”. The correct file is provided for your kind reference and attached. The authors would like to apologise for any inconvenience caused. DOI of original article: https://doi.org/10.1016/j.matchar.2020.110671 © 2021 Elsevier Inc.

Materials Characterization

Corrigendum to microstructure characterization and tensile properties of CMT-based wire plus arc additive manufactured ER2594 [materials characterization 169 (2020) 110671] (Materials Characterization (2020) 169, (S1044580320321422), (10.1016/j.matchar.2020.110671))