Hatia, India
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Mishra A.,NIFFT | Khobragade N.,NIFFT | Sikdar K.,NIFFT | Chakraborty S.,National Institute of Technology Rourkela | And 2 more authors.
Advances in Materials Science and Engineering | Year: 2017

Present research aims to assess the influence of nanocrystalline mica (NM) dispersion (10, 15, 20, and 25 vol.%) in hydroxyapatite (HA) matrix on its mechanical and tribological properties and bioactivity. Nanosized mica (NM) was prepared by mechanical milling of commercial mica powder. The composite was prepared by mechanically mixing the milled mica with HA and consolidated by microwave sintering at 1200°C for 10 min. Phase characterization by X-ray diffraction (XRD) shows dissociation of HA into β-TCP (tetra calcium phosphate) in sintered compact. Estimated densification is the highest (98%) with 20% NM addition. HA-20%NM also shows an optimum combination of mechanical (hardness 2.80 GPa and indentation fracture toughness 1.51 MPa m1/2) and tribological properties (wear rate 1.6 × 10-6mm3/Nm). Scanning electron microscopy (SEM) of worn out surface elicits that wear mechanism is governed mainly by delamination and abrasive mode. Biocompatibility assessment in simulated body fluid (SBF) indicates that no elemental change occurs (confirmed by energy dispersive spectroscopy (EDS)) even after 60 days of emersion. It reveals that the optimized composition is satisfying fundamental requirements of an implant material. © 2017 Anumeha Mishra et al.

Das R.,KIIT University | Sarmah A.,KIIT University | Sood A.,NIFFT
Procedia Engineering | Year: 2014

Extrusion process has proved its potential in bulk metal forming process since the industrial development. The better product quality, mechanical property and the strength of the extruded products are the advantages in extrusion process. Multi-hole extrusion is used where pressure required for extrusion is in excess of press capacity. It is used for the production of small and precise products such as parts used in automobiles, health-care and aviation industries. The different process parameters affect the extrusion process and quality of the extruded products. In the present investigation, finite element analysis is carried out to study the effect of loaction of holes on the die, die pockets and the extrusion speed on the extrusion load, efective strain and the extruded product length. Extrusion load is found to increase with increase in extrusion speed. The die pockets help in reducing the extrusion load. The effective strain, which provides the information about the work hardening of the material during the extrusion process is dependent of the above said process parameters. The extruded product lengths become more uniform when die pockets are made. The selection of process parameter is based upon the required quality of the product. © 2014 The Authors.

Tiwari A.,BIT Mesra | Mandal A.,NIFFT | Kumar K.,BIT Mesra
Materials Today: Proceedings | Year: 2015

Quality of machined surface strongly depend on the selection of optimal parameter settings and type of machining process. Electro-chemical machining (ECM) offers several unique feature, like higher machining rate, better surface finish, and it is suitable for machining a wide range of materials. In this regard, an attempt has been made to develop a mathematical model for responses i.e. metal removal rate (MRR) and surface roughness (SR) through regression analysis for electro-chemical machining on EN 19. And analysis of variance (ANOVA) test is perform to check the aptness of the developed mathematical models. The performance for ECM process is optimized through Non-dominated Sorting Genetic Algorithm-II (NSGA-II) for maximizing the metal removal rate and minimizing the surface roughness. Through this non-dominated optimum parameter settings has been obtained and reported. © 2015 Elsevier Ltd.

Malapati M.,NIFFT | Sarkar A.,Jadavpur University | Bhattacharyya B.,Jadavpur University
Advanced Materials Research | Year: 2011

Electrochemical micromachining (EMM) appears to be promising as a future micro machining technique since in many areas of applications; it offers several advantages including electronic, biomedical and MEMS/NEMS applications. Present paper will highlight the influence of various EMM process parameters i.e. machining voltage, electrolyte concentration, frequency pulse period and duty factor on machining performance criteria e.g. material removal rate and machining accuracy to meet the micromachining requirements. Some of the experiments had been carried out on copper to investigate the most effective zone, which gives high machining accuracy with appreciable amount of material removal rate. Attempt has also been made to study and compare the surface condition of the machined micro-holes through SEM micrographs. From the analysis of test results and SEM micrographs it can be observed that optimum value of frequency pulse period is about 200 μsec and duty factor is about 20% which will produce accurate micro-holes with highest possible amount of material removal. © (2011) Trans Tech Publications, Switzerland.

Malapati M.,NIFFT | Sarkar A.,Jadavpur University | Bhattacharyya B.,Jadavpur University
International Journal of Machining and Machinability of Materials | Year: 2012

Electrochemical micromachining (EMM) appears to be a very promising micromachining technique in nearby future. Use of copper as a conductive material in microchips needs generation of complex profiles in copper foil. EMM can be utilised for generating micro-profiles in copper foils, which urgently needs a lot of investigation. For fulfilling various research objectives and needs of EMM, the present research highlights the development of EMM system setup and feasibility study of machining micro-channels. Experimental investigation on the developed EMM setup considering the influence of process parameters on micromachining criterion have been performed based on Taguchi method of robust design. From the results, optimal parametric settings for the responses are electrolyte concentration of 50 g/l, applied voltage of 7 V, frequency of 30 kHz, duty factor of 0.15 and tool feed rate of 312.5 μm/s. Second order regression equations have also been developed to search out the best parametric combination for achieving different micromachining characteristics. Copyright © 2012 Inderscience Enterprises Ltd.

Tiwari A.,BIT | Mandal A.,NIFFT | Kumar K.,BIT
Materials Today: Proceedings | Year: 2015

Objective: of thework is to achieve best optimal combination of various input parameter for radial over-cut (ROC) in electrochemical machining for EN 19 tool steel with copper electrodeapplyingtaguchitechnique. The electrolytic concentration, voltage, feed rate and inter electrode gap are considered as input process parameters for electro-chemical machining. Optimal combination of selected input parameters utilized in order to achieve the minimum overcut effects for better accuracy of shape features. The experiments were undertaken as per taguchiL27 orthogonal array (OA) with three levels for each machining parameter. The Design of Experiments of L27 orthogonal array was tabulated with the aid of Minitab software version 16. The impact of each machining process parameterswere predicted by performing ANOVA at 95% level of significance. This paper also stress on the development of mathematical model by using regression analysis, second order response equation obtained between the controllable variables and parametric interactions for overcut as response. From the obtained results, it wasobserved thatvoltage and concentrationwere the most dominating criteria for minimization of overcut. © 2015.

Sahoo S.,Indian Institute of Technology Kharagpur | Kumar A.,NIFFT | Dhindaw B.K.,Universiti Sains Malaysia | Ghosh S.,Indian Institute of Technology Kharagpur
Materials and Manufacturing Processes | Year: 2013

Mathematical modeling of the solidification behavior of Al-33 wt% Cu strips in a twin roll caster at speeds varying between 0.079 m/s to 3.98 m/s predicted that at high casting speed strips will have layered structure with distinct morphology. The model was validated by production of Al-33 wt% copper strips in a laboratory twin roll caster. As per the prediction from the model the high speed cast strips had layered structure with zones near the roll surface showing higher hardness as compared to the interior. Copyright © 2013 Taylor and Francis Group, LLC.

Pathak A.K.,NIFFT
Advanced Materials Research | Year: 2012

Lean manufacturing production system considers the expenditure for any goals other than the creation of value for the end customer to be wasteful. Only operation adds value to the product and other functions such as inspection, transportation, and delays of a permanent or temporary nature are waste and should be eliminated. The beginning of lean manufacturing can be seen in Just In Time (JIT). It was first implemented in Ford automobile in the form of line assembly. Lean manufacturing is based on pull system. In the pull system parts are produced when they are pulled by the process before that. Lean manufacturing defines the value of a product or a service with the customer point of view not on the basis of type of technology and amount of labour. In the lean manufacturing the organization is treated as a single unit. Team work is more important than individual effort. The implementation of lean manufacturing reduces lead time, reduces work in progress (WIP), saves floor space, increases productivity, improves quality and reduces overall cost. In this paper various aspects of lean manufacturing have been examined and discussed. © (2012) Trans Tech Publications.

Roy D.,NIFFT | Raghuvanshi H.,NIFFT
Journal of Non-Crystalline Solids | Year: 2011

The crystallization behavior and thermal stability of amorphous phases of Al 65Cu 20Ti 15 alloy obtained by mechanical alloying were investigated by using in-situ X-ray diffraction and differential scanning calorimetry (DSC) under non isothermal and isothermal conditions. The result of a Kissinger analysis shows that the activation energy for crystallization is 1131 kJ/mol. The higher stability against crystallization of Al 65Cu 20Ti 15 amorphous alloy is attributed to the stronger interaction of atoms in the Al-Cu-Ti system and formed of complicated compound like Al 5CuTi 2 and Al 4Cu 9 as primary phases. The isothermal crystallization was modeled by using the Johnson-Mehl-Avrami (JMA) equation. The Avarami exponents suggest that the isothermal crystallization is governed by a three-dimensional diffusion-controlled growth. © 2011 Elsevier B.V. All rights reserved.

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