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J. P. Misra ¹, P. K. Jain ¹, D. K. Dwivedi ¹, N. K. Mehta ¹

Affiliations
1 Dept of Mechanical and Industrial Engg., Indian Institute of Technology, Roorkee, IN

Abstract

From last few decades, the gear finishing processes draw the attention of researchers to improve the service performance of gears which is a very essential element in many crucial products for mankind namely automotive products, ships, wind-power systems, machine tools or general gear boxes. This paper presents the experimental investigation of bevel gear finishing using an abrasive bonded mitre gear in an indigenously designed and developed experimental setup. The experimentation has been carried out to evaluate the effect of finishing time and rotating speed of workpiece on improvement in surface quality of gear teeth profile and material removal rate (MRR) of the process. Surface quality of the finished gear has been also analysed and it was found that the process produces a smooth surface by reducing irregularities. Furthermore, future scopes of the process are also highlighted.

Keywords

Bevel Gear, Gear Finishing, Abrasives, Surface Integrity.

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Chaitanya Sharma ¹, D. K. Dwivedi ¹, P. Kumar ¹

Affiliations
1 Mechanical and Industrial Engineering Department, I.I.T., Roorkee, Uttarkhand-247667, IN

Abstract

Friction stir welding is one of the most suitable welding processes to join aluminum alloys, thanks to many economical and technical advantages associated with its use. This paper investigates effect of friction stir welding on the microstructure and mechanical properties of solid solution hardening Al-Mg-Mn aluminum alloy. Friction stir weld joints were developed using optimum combination of rotary speed and welding speed. The microstructure evolution in friction stir weld joints was studied by optical microscopy. Fine recrystallized grains were observed in weld nugget zone while thermo-mechanically affected zone showed distorted and unrerystallized grains. Microhardness profiles and stress-strain curves were developed for friction stir weld joints and base material. Friction stir weld joints showed mechanical properties approximately equal to base material. Further, fracture surfaces were investigated using scanning electron microscope to study the mode of fracture.

Keywords

Friction Stir Welding, Microstructure, Mechanical Properties, and Solution Hardening Aluminum Alloys.

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Vandita Rao ¹, D. K. Dwivedi ¹

Affiliations
1 Amorphous Semiconductor Research Lab, Department of Applied Science, Madan Mohan Malaviya University of Technology, Gorakhpur – 273010, Uttar Pradesh, IN

Abstract

Objective: To understand the structural and characteristic properties of phase change materials which are predominant for development of existing as well as future technologies. Crystallization kinetics and unlikeness between the amorphous and crystalline phases are the two main characterizations of phase change materials. Methods: This review demonstrates the different crystallization techniques in details. For re-writable DVD, the crystallization rate should be large enough to enable a high data rate at inflated temperature. Findings: Se-Te based chalcogenide alloys are frequently used in optical memory devices. But due to some drawbacks of these alloys, we have made an attempt to enhance their properties by addition of third element. Activation energy of crystallization (using Kissinger model) and rate of crystallization for ternary glassy alloys have been listed. It has been found that Ge is the favorable dopant for data storage applications because it has low activation energy of crystallization and high rate of crystallization. Applications: The chalcogenide fibers are used in fiber optic chemical sensor systems for remote detection and identification as well as detecting chemicals in mixtures.

Keywords

Chalcogenide Glasses, Crystallization Techniques, Kissinger Model, Phase Change Materials, Rate of Crystallization

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N. K. Soni ¹, K. K. Tiwari ¹, D. K. Dwivedi ², Vikash Singh ³, V. K. Singh ³, A. K. Shukla ⁴

Affiliations
1 Department of Chemistry, University of Allahabad, Allahabad, 211 002, IN
2 Electronics Department, Ewing Christian College, Allahabad, IN
3 Rashtriya Post Graduate College, Jamuhai, Jaunpur-222001, Uttar Pradesh, IN
4 Department of Chemistry, S.P. Mukherjee Government Degree College, Allahabad, IN

Abstract

Various thermodynamic properties viz. acoustic impedance, Z, intermolecular free length, Lr molar sound velocity, R, molar compressibility, W, and molecular association M_A, have been computed for five binary liquid mixtures (Dimethylcarbonate (DMC) + methanol, DMC + cyclohexane, methanol + cyclohexane, DMC + benzene, and methanol + benzene) at 298.15 K. Interactions between the components of binary systems are studied in terms of excess acoustic impedance, Z^E, excess intermolecular free length, L_f^E deviation in molar sound velocity, ΔR, deviation in molar compressibility, ΔW, and deviation in ultrasonic velocity, Δu. Sign and magnitude of the excess properties give an estimate of strength of the unlike interactions in a iquid mixture. Small positive values of L_f^E and negative values of Z^E and Δu signify the existence of weak interactions between component molecules of all the binary systems. Moreover, an attempt has also been made to examine the validity of several theories and relations, viz. free length theory, Nomoto relation, Junjie relation, Van Deal & Vangeel ideal mixing relation and collision factor theory for the theoretical predictions of ultrasonic velocity in the systems under consideration.

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J. D. Pandey ¹, Ranjan Dey ¹, N. K. Soni ¹, R. K. Mishra ¹, D. K. Dwivedi ²

Affiliations
1 Department of Chemistry, University of Allahabad, Allahabad-211002, IN
2 Department of Electronics, E.C.C., Allahabad, IN

Abstract

Flory's statistical theory has been extended for the computation of internal pressure, isentropic compressibility, isothermal compressibility and Pseudo Gruneisen parameter of binary mixture nitrobenzene+benzene at pressure up to 10 MPa and at two different temperatures (293.15K, 303.15K & 313.15K). For a comparative study of the isothermal compressibility of this system, equation of state based on the psuedo spinodal hypothesis developed by Baonza et al has also been utilized to deduce the isothermal compressibility of this mixture. The computed values of P_int, β_T, β_s and Γ have been compared with the experimental findings available in literature. Satisfactory agreement has been found between experimental and theoretical values.

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P. K. Ghosh ¹, D. K. Dwivedi ², P. S. Mishra ³

Affiliations
1 Department of Mechanical Engineering, University of Roorkee, Roorkee, IN
2 Department of Mechanical Engineering, Regional Engineering College, Hamirpur, IN
3 Department of Materials and Metallurgical Engineering, University of Roorkee, Roorkee, IN

Abstract

A commercially available Ni base eutectic alloy powder (EWACI005EC) was modified by mechanical mixing of 2wt.% Al powder with it. Hard surfacing of mild steel substrate was carried out by gas thermal spraying of both the original & modified powders. Oxidation resistance of the hard surfacing produced by using both the original & modified powders was studied under constant heating at temperatures of 800, 850 and 900°C for 8 hours and also under cyclic heating up to 15 cycles where, each cycle was designed as heating for a period of 2 hours at temperature of 800°C followed by cooling down to temperature of 300°C. The characteristics of microstructure and hardness of base metal and both the coatings of original and modified powders were studied. Wear resistance of the hard coatings of both the powders were studied at ambient temperature using “PIN on DISC” wear testing method at nominal loads of 2.5 and 3.5 kg. It was found that at all the test loads, the coating of the original powder is having comparatively better wear resistance than that of the coating of the modified powder Under the cyclic heating original powder coating was marked to be comparatively better oxidation resistant than the modified powder coating. But, at a given temperature the hard coating of the modified powder was found comparatively better oxidation resistant than the same produced by spraying the original powder.

Keywords

Thermal Spraying, Ni Base Eutectic Alloy Powder, Modification of Alloy Powder, Hard Surfacing, Micro Structure, Hardness, Wear, Oxidation Resistance.

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