Other In Formations

M.E Project :- Creep, wear resistance & corrosion behaviour & characterizations of

advanced Mg alloys & Mg alloys based composite materials. Magnesium alloys have become attractive candidate for applications in automotive, aerospace & electronic industries owing to their high specific strength, which leads to weight reduction, resulting in considerable economic advantage. To achieve further, application of Mg based alloys in automotive engine and transmission components of commercial vehicles it is necessary to improve their creep and wear resistance. In fact, the creep resistance of Mg cast alloy is found to be limited to 473K. A considerable improvement in the creep properties of Mg alloys can be achieved potentially by non metallic reinforcement. Thus, Mg metal matrixes composites (MMCs) are advanced materials with potential for high temperature applications. Reinforcement by second phase has the advantage of keeping the weight light, and increasing the specific strength, elastic modulus and creep resistance. Of several available MMC systems, fibers or particulate reinforcements are of main interest. The present work was initiated to provide a systematic assessment of creep and wear properties of cost effective Mg based composites having AE42 as matrix and Al2O3, SiC as reinforcement with varying volume fraction. However there have been very few investigations on the creep and wear behaviour of Mg-MMCs as compared to Al-MMCs. In view of its potential applications in engine components it is essential to understand the creep and wear behaviour of the composite. As corrosion resistance of Mg based alloys are very poor, so to improve the same, laser treated MRI 230D alloys was investigated to compare & characterized the corrosion behaviours. This project is in collaboration between IISc, Bangalore and GKSS Research Centre, Germany. All alloy and composite materials are specially prepared for automotive application using squeeze casting technology. The creep behaviour of the materials (AE42+20% Saffil® MMC & AE42 matrix based hybrid MMCs (AE42+ 15% Saffil® + 5% SiC, AE42 + 10% Saffil® + 10% SiC, AE42 + 10% Saffil® + 15% SiC) were examined to study the effect of high temperature and stress on creep mechanisms as well as microstructure. Impression creep technique is employed to generate creep data over a wide range of stresses for Hybrid & 20% Saffil® with AE42 matrix composites. Material flow behaviours in the adjacent region to indenter and variation of pressure & stress in that region are also analyzed. Observation of microstructural changes & XRD analysis are carried out on surface as well as sub surfaces of the tested samples. The hybrid composites exhibit creep resistance comparable to 20% Saffil® composite. The dry sliding wear behaviour of AE42 alloy and all above composites were investigated in dry sliding condition using pin-on-disc configuration as per ASTM G99 in the load range of 5 to 40 N and at the sliding speeds of 0.838 m/s for a constant sliding distance of 2.5 km. At the sliding speed 0.838 m/sec the hybrid composites show better wear resistance at all load levels than alloy and 20% Saffil® composites in both transverse and longitudinal directions. Among the hybrid composites, AE42+ 10% Saffil® + 10% SiC shows better wear resistance than others. At high load (40 N) alloy exhibited better wear resistance than 20% Saffil® composite & there was a crossover in wear rate. It was observed that oxidation and abrasion appear are the dominant wear mechanisms at lower loads and it changes to delamination at higher loads. The detailed study about wear mechanisms, using scanning electron microscopy was carried out to interpret the wear behaviour of these materials. Here, an attempt was made to enhance corrosion resistance of MRI 230D Mg alloy by laser surface treatment. The study included a detailed characterization of laser treated surface in terms of microstructure and phase analysis. Corrosion behaviour of the as cast alloy and laser surface treated alloy was studied in detail. The corrosion resistance of the laser surface treated alloy significantly improved in a 5 wt.% NaCl solution because of grain refinement and redistribution of the intermetallic phases following rapid solidification associated with the process.

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B.E . Project: - Development of Al-AlN Composite by powder metallurgy techniques Metallic composite materials are component of two or more different metals. Intermetallic compounds in a metallic matrix posse a particular microstructure arrangement. The properties of composite materials are achieved by proper distribution as well as orientation of hard particles, strong fibers or a layer in the softer matrix. Structure of the matrix clearly shows the presence of two different materials, which is present in large amount, is called matrix. The other materials are sometimes referred as a reinforcing phase. It could be present either as three dimensional particles, layers or long fibers. Composites are artificially produced multiphase materials having desirable combination of the best properties of the constituent phases. Dispersion strengthened composites fall within the particle reinforcement classification. Input strength is achieved by extremely fine particles of the dispersed phase, which hinders the dislocation motion, i.e., the strengthening mechanism involves interaction between the particulate and dislocation that may be treated on the atomic level. Composites materials are used in variety of components such as aerospace, marine, automobile etc. Al-AlN composites can achieve high specific strength, high specific stiffness and improved high temperature strength, which are very much desirable for making various components. The need to sustain high temperature strength and abrasions, various aircraft parts can be made by composite materials. AlAlN is a unique system for such application because of its excellent high temperature properties and high strength to weight ratio. Al-AlN system is frequently used as a substitution of Al-Al 2O3 or Al-SiC system. Wettability of second phase particles in molten Al is poor and to increase the wettability sophisticated N2 purging system is required and aluminum melt needs some addition like MgO or Mg ribbon. Still the yield of the second phase particles is poor and their dispersion in the matrix is not homogeneous. The P/M technique has become indispensable route for making the various composites materials. Extensive literature study survey reveals that Al-AlN system has been developed primarily by melt infiltration techniques. Though the conventional compaction and sintering process has been applied, but in depth has not been done in the light of compaction and sintering mechanism. The present study aims at producing AlAlN by varying AlN content and applying conventional P/M technique where variation in compacting pressures and sintering temperature has been done. In the present investigating Al powder was mixed with AlN in various proportions from 10 vol% to 30 vol% and subjected to various compacting pressures. The green compacts pressed at 300Mpa were sintered at various temperatures ranging from 2000C to 6000C, with an interval of 1000C in an Ar atmosphere for one hour. The green density, hardness and % porosity were measured .The sintered density; % porosity and hardness of sintered components were also evaluated. Extensive microstructural characterization was carried out under optical and electron microscope (few only). This study reveals that AlN particles hinder, the cold welding of Al particles and it decreases with increase in AlN content. AlN particles are homogeneously distributed in the matrix at high compacting pressure. The increase in AlN content decreases the plasticity of Al. The hardness and % porosity decrease with increasing sintering temperature. It was found that the composite with 30 vol % AlN does not show much improvement after sintering and beyond 10 vol % AlN in Al gives detrimental effects in terms of hardness, density and % porosity.

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O T H E R

I N F O R M A T I O N S:-

Key Skills : - Welding Process, Welding Metallurgy, Automobile & Automotive materials / Auto components, Industrial Relations, Third party Inspection , Materials Selection / replacement, Vendor development/ Vendor quality/Supplier audit approval & source materials approval, Product Approval, New Product Design & Development, Process Development, Quality Assurance, Material Testing & Characterization, Metallography, Light metals alloys & composite .

Summary of skills: Welding – Quality Assurance / Control of all types of welding consumables, Welding process approval / Product approval, 3rd party inspections & approval of different reputed agencies, Different welding processes & Metal Joining Techniques, process development/ control, Inspection of welded product Automobile / Auto Component – Selection / inspection / replacement / development & QAP of auto components and automotive materials (structural steels, forgings, casting, heat treated, Sheet Metal Components, fabricated components, different metallic / non metallic materials). Engine Parts - Cylinder Block, Cylinder Head, Crank Case, Cylinder liner, Piston, Combustion Chamber, Connecting Rod, Piston Ring, Crank Shaft, Cam Shaft, Exhaust & Inlet Valve, Rocker lever valve, Oil sump, Inlet & exhaust manifold, Circlip etc. Transmission Parts – Drive Shafts, Ring Gear, Differential Gear, Spring Saddle, Torsion Bar, Front Axle Beam, Stub Axle, Synchronized Ring, Crown Wheel, Drive Flange, Lay Shaft, Planetary Gear, Shift Sleeve, Pinion etc Press & Fabricated Parts – Shim, Spacer, Washer, Mounting Brackets, Shaft Seal etc. Vendor Development – Vendor development and source approval, Supplier Development, Vendor quality audit, Vendor development from raw material to final stage & source approval for vendors by inspecting their technical capabilities, QAP for Supplier Development & supplier audit for continual improvement Manufacturing & Materials Characterization – Metallurgy, Manufacturing processes ( Casting Forging Rolling Extrusion Welding Metal forming), Mechanical Metallurgy , Mechanical behaviours of metal ceramic & polymer materials, Materials testing processing & Characterizations, Selection, analyze & applications of different engineering materials, Electron Microscopy / Microscope ( SEM) Quality System & Standards QMS (ISO 9001) / EMS (ISO 14001) / TS 16949, Working knowledge of BS, IS, DIN, JIS, DBL & MAN Std. on automotive materials, Core tools of 16949 as TQM, SPC, FMEA, APQP, PPAP, MSA etc ASME, BIS related to welding, ASTM related to materials testing.

Applications – Failure analysis, Nanotechnology, Magnesium Aluminium alloys Steel & Cast irons, Hard facing or reclamation products, Creep wear / tribology / friction test & corrosion study of light metals alloys & composite for automotive & aerospace applications, Different processing and manufacturing techniques of composite materials (stir mixing, powder metallurgy, thixo-casting, preform infiltration and squeeze casting), Knowledge about the properties of different varieties of raw materials as metal powders / ferro alloys / complex oxides / sands / clays / carbonates / fluorides / alumino-silicate / liquid & solid organic binders, Handling third party inspections / testing for Homologation of Vehicles, 3

Courses taken at IISc (Indian Institute of Science, Bangalore ) as part of the Post Graduate degree requirement : -

Numerical Methods - Taught by Prof. Govindan Rangarajan Metallurgical Thermodynamics - Taught by Prof. T. A. Abinandanan Structure & Characterization techniques of Materials - Taught by Prof. V. Jayaram & Prof. S.Ranganathan Transport Phenomena in Materials processing (Fluid Mechanics & heat transfer) – Taught by Prof. Govind S.Gupta Mechanical Behaviour of Materials – Taught by Prof. U. Ramamurty Solidification Process - Taught by Prof. K. Chattopadhyay Light metals, Alloys and Composites - Taught by Prof. Subodh Kumar Diffusion controlled interaction in Solid state – Taught by Prof. Aloke Paul Deformation and Failure Mechanisms at elevated Temperatures – Taught by Prof. A. H. Chokshi Interfacial Phenomena in Materials Processing – Taught by Prof. S. Subramanian Single Crystal growth & Characterizations techniques – Taught by Prof. H. L. Bhat Laboratory experiments in Metallurgy – Many Faculties

Exposures to various instruments : JEOL 40 Scanning Electron Microscope - Independent user FEI Sirion Scanning Electron Microscope with EBSD, Back scattered & Secondary images, EDX / WDX attachments Transmission Electron Microscopy Atomic Force Microscopy Optical Carl Zeiss make Microscope - Independent user JEOL’s X –Ray diffraction Unit for material characterization & different techniques - Independent user Pin on Disc type wear testing Machine - Independent user Creep testing Machine (Compression & Impression type) - Independent user Different types of hardness-testing machines ( eg. Brinell . Vickers, Rockwell, Knoop etc.) -- Independent user Shimadzu Dynamic Ultra Low Load Micro hardness Tester Shimadzu Micro hardness Tester - Independent user Zwick make micro hardness tester - Independent user Leitz make micro hardness tester - Independent user XRF analyzer for chemical analysis of any type of materials - Independent user Spectrometer for chemical analysis of metallic materials - Independent user LECO carbon & sulphur analyzer / LECO Oxygen/Nitrogen Analyzer - Independent user

Inductively coupled plasma (ICP) spectroscopy – For chemical analysis in solution state Heat treatment furnaces in laboratory scale - Independent user Impact testing machine - Independent user Ferrite meter - Independent user Zwick make Universal tensile testing machine - Independent user Instron 8032 Testing Machine Instron Servo Hydraulic Machine – for compact testing Diffusible hydrogen analyzer - Independent user

Professional affiliation:ASME - American society of Mechanical engineers IIW - Indian Institute of Welding IIM - Indian Institute of Metals

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Conferences attended: 1. Nineteenth Annual Symposium on Metallurgical and Materials Research, January 12-13, 2006 , IISc , Bangalore. 2. The Eighth International Conference on Nanostructure Materials (Nano-2006), August 20-25, 2006, NSSC, Bangalore. 3. The 20th Annual Symposium on Metallurgical and Materials Research, January 4-5, 2007, IISc, Bangalore. 4. Mechanical Behaviour of Systems at Small Length Scales- 2 , 5-9 February, 2007 , Faculty Hall , IISc, Bangalore. 5. Advances in Materials Engineering, 4-6 July, 2007, NSSC, IISc, Bangalore

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