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Dissertations / Theses on the topic 'Physical Metallurgy'
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Zhu, Yao-Hua. "Physical metallurgy of Zn-Al based alloys." Thesis, Aston University, 2006. http://publications.aston.ac.uk/21803/.
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Peters, Michael Andrew. "The physical metallurgy of β/β' NiTi/Ni₂TiAl alloys." Thesis, University of Cambridge, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.624799.
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Quariguasi, Netto Pedro Gutemberg. "Mathematical and physical modelling of a single-belt casting process." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0016/NQ44560.pdf.
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Kim, Hyoungbae 1969. "Physical modelling of two phase flows in ladle-shroud systems." Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=20914.
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The onset of a 'late' rotating vortex over an off-centre drain nozzle at 2/3 radius was studied in an 1160-mm diameter tank. It was found that using a sloped bottom ladle could be beneficial in terms of steel yield, provided the exit nozzle is located 'centrically'.Miner modification of the nozzle (skewed nozzle) to impart a radial component of velocity to the spinning vortex core was found to be effective in making AMEPA system sensitive to early slag entrainment phenomena by diverting the core away from the central vertical axis of the nozzle.
A 0.75 scale water model was constructed to simulate the flow of liquid steel through a ladle shroud in the presence of gas infiltration. It was found that the ladle shroud slag detector could be temporarily 'blinded' by gas bubbles or permanently blinded by a standing submerged gas jet.
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Verhelst, Dominic. "Physical modelling of gas stirred metallurgical reactors containing two liquids." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59908.
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The present work represents a study of the mixing and slag entrainment behaviour of metallurgical processes. Two immiscible fluids were mixed in a model reactor, equipped with a single centrally located tuyere, through which air was blown.For low energy input systems, it was found that the thickness of the second liquid phase can significantly affect the mixing time of the bulk phase by altering the fluid flow pattern of the liquid. The entrainment of the upper phase into the lower phase was also affected by the thickness of the upper phase, as well as by the intensity of bath agitation. At low flowrates, the number density of entrained droplets was constant with time, increasing with increasing agitation and thickness of the layer. The air flow required for the transition in the entrainment behaviour increased with an increase in the thickness of the upper phase.
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Ray, Shamik. "On the application of physical and mathematical modeling to predict tundish performance." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66779.
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ABSTRACT In the continuous casting process, the tundish not only serves as an intermediate buffer, but it also acts as a useful reactor for liquid steel refining. Modern tundishes are now designed to carry out different metallurgical operations, such as inclusion separation and flotation, alloy trimming, calcium doped inclusion modification, and thermal homogenization. To carry out such operations effectively, fluid flow inside a tundish plays an important role. It is now a proven fact that the insertion of different types of flow modifying devices can alter flow patterns within the tundish and thus affect the performance of the tundish significantly. Due to adverse operating conditions, direct experimental investigations are difficult to carry out. For that reason, physical and mathematical modeling is predominantly used to study tundish performance. Parameters like 'Residence Time Distribution' (RTD), tracer dispersion, velocity distribution, inclusion separation, etc. were mostly used to study and predict the performance of a tundish. Slag entrainment, though, is a vital problem during ladle changing that has been given less attention. In this research, it is intended to form a physical and mathematical modeling framework, to study and predict the performance of a 12 t, delta shaped, four strand, billet casting tundish. A full scale water model was studied both physically and mathematically. The phenomenon of slag entrainment occurring during a ladle changing operation was used as the key parameter to assess tundish performance. The amount of slag entering the 'Submerged Entry Nozzle' during a ladle change was measured to quantify the performance of different flow modifying arrangements. It is believed that the results of tests carried out under transient conditions can give a fairly good idea about tundish performance at steady state. To strengthen this belief, mathematical modeling of inclusion sRÉSUMÉDans les procédés de coulées continu, les paniers répartiteurs ne servent pas seulement comme interface tampons, mais aussi comme un réacteur efficace pour raffiner l'acier. Les paniers répartiteurs modernes sont maintenant conçus pour effectuer différentes opérations métallurgiques comme la séparation des inclusions et leur flottation, l'ajustement fin de la nuance, le contrôle de la température de surfusion, la modification des inclusions par ajout de calcium et l'uniformisation de la température.Pour y arriver efficacement, l'écoulement du fluide dans le panier joue un rôle majeur. Il est maintenant prouvé que l'ajout de différents systèmes pour modifier les écoulements peut altérer les patrons d'écoulement dans le panier et en changer significativement la performance. Due aux conditions d'opérations difficiles, des investigations par expérimentation directe sont très difficiles. Pour cette raison la modélisation physique et mathématique est largement utilisée pour étudier la performance des paniers répartiteurs. Des paramètres comme la «Distribution des temps de résidence (RTD)», la dispersion d'éléments traceurs, le champ de vélocité, la séparation des inclusions, etc. sont largement utilisés pour étudier et prédire les performances d'un panier. L'entrainement du laitier, quoiqu'un problème vital lors du changement de creuset, a pourtant reçu moins d'attention. Dans cette recherche, le but est de développer une méthodologie de modélisation physique et mathématique pour étudier et prédire la performance d'un panier répartiteur de douze tonnes de forme triangulaire à quatre jets de coulée. Un modèle aquatique de grandeur nature fut étudié physiquement et mathématiquement. Le phénomène d'entrainement de laitier durant les opérations de changement de creuset fut utilise comme paramètre clé pour quantifier la performance du panier. La$
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Moon, Ki-Hyeon. "Physical and mathematical modeling of a metal delivery system for a single belt caster." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=84868.
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In order to design the metal delivery system for the single belt caster in the MMPC (McGill Metals Processing Centre) foundry, water modeling and mathematical modeling were carried out for a newly devised three-chamber type tundish. Water flow in the acrylic tundish was visualized using dye injection. Flow velocities were also measured using a Dual Nd-YAG PIV (Particle Image Velocimetry) system. A commercial FEM code, FEMLAB 2.3 was adopted to predict the velocity field and temperature profile within the tundish, especially in the output chamber. Calculated results were validated with the PIV measurements. A full-scale water model was built for the single belt caster to simulate the casting operation and to validate the optimized delivery system. Temperature profiles for the tundish wall were also predicted to choose a suitable method of preheating and to determine refractory wall specifications.A three-chamber type tundish comprising an entry chamber, a head control chamber and an output chamber was designed to provide clean metal and strips of uniform thickness across the width of the belt. An output chamber proved to be essential for removing the bubbles and for obtaining a uniform film of water on the substrate by preventing strong hydraulic jump. The output chamber had to be completely closed for rapid bubble removal. For rapid filling of the output chamber at start up, the starting stopper proved to be essential. The 3-hole type nozzle, proved to be more effective for removing the bubbles, was found to have problems in terms of strongly impinging jet flow and non-uniform lateral velocities.
Using mathematical modeling and full scale water modeling, including PIV measurements, the "FD" type nozzle, which had a multi channel flow modifier in the output chamber and a slot type inlet nozzle, was found to be the best in terms of rapid bubble removal and uniform distribution of flow. This was achieved by a dramatic reduction in the strength of the vertically impinging flow towards the belt. However, this "FD" type nozzle generated a dead zone near the triple point within the output chamber. To remove the dead zone, a gently sloped shape insulator was inserted between the tundish back wall and the belt.
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Lewis, David. "Physical and electronic structure studies of CuZn and CuPd alloys." Thesis, University of Liverpool, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367165.
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Gateaud, Arnaud. "Physical and chemical mechanisms of lubricant removal during stage I of the sintering process." Link to electronic thesis, 2006. http://www.wpi.edu/Pubs/ETD/Available/etd-040606-161143/.
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Nickoletopoulos, Nicholas. "Physical and numerical modeling of steel wire rod fracture during upsetting for cold heading operations." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=37796.
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A comprehensive methodology to physically and numerically model upsetting in cold heading was developed.The physical model was a Drop Weight Test with a guided pocket-die set capable of approximating industrial cold heading conditions. The results show that the test is sensitive to the critical parameters for cold heading. These include surface quality, residual element level, nitrogen content, microstructure, decarburization, and specimen geometry. The test is capable of assessing the fracture behavior of cold heading materials.
One goal of the study was to reveal differences in fracture behavior with varying steel sources. Accordingly, the matrix of test materials consisted of grade 1038 steels from three different steel sources.
Material preparation and conditioning of test materials approximated industrial procedures for cold heading materials. These procedures included hot rolling, controlled rod cooling, descaling, straightening, lime coating and lubricating, and wire drawing. Spheroidization of test specimens was performed in an industrial batch furnace using an industrial heat treatment cycle.
A finite element program (FEM) enabled the simulation of upsetting in cold heading. The inputs required to model the cold heading process include flow stress behavior and friction conditions representative of cold heading. These inputs were obtained using the CANMET Cam Plastometer and the Friction Ring Test.
The Cockcroft and Latham fracture constants for an as-rolled and a spheroidize annealed 1038 material were computed by FEM modeling and the critical values were calibrated using the Drop Weight Test. The fracture criterion constant was found to be independent of strain path for upsetting in cold heading and thus is material-related.
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Brauer, Stephan F. "The kinetics of rapid crystallization of metallic glasses." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=39382.
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Time-resolved x-ray scattering has been used to study the kinetics of polymorphic crystallization of amorphous metals on time-scales varying from minutes to milliseconds. Using a high flux synchrotron beamline and fast position-sensitive detector system, simultaneous wide and small angle scattering patterns from the transforming material have been acquired in situ, with time-resolution as short as 3ms. A fast pyrometric temperature controller has been developed to change and regulate the sample temperature with microsecond response. Two alloys have been identified in which crystallization proceeds by thermally activated nucleation and growth of a single equilibrium phase at all observable transformation rates. Crystal volume fractions as small as 10$ sp{-4}$ can be measured and the results are well explained by a simple nucleation and growth model. There is no evidence for a nucleation transient. Small angle scattering from such alloys reveals an increase in intensity prior to crystallization followed by a rise commensurate with the crystallization itself. In all other studied alloys however, as the transformation rate is increased, the crystallization mechanism changes such that transient crystal phases are formed en route to the equilibrium structure. Two new metastable phases have been crystallographically identified. At high equilibrium rates, the kinetically favored phases are those which require the least atomic rearrangement from the glassy state.
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Sagoe-Crentsil, Kwesi Kurentsir. "The effect of misfit on morphology and kinetics of plate shaped precipitates." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/29380.
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Lattice misfit and its effect on the morphology, interfacial structure and kinetics of plate shaped precipitates are investigated in this study. The 7-Ag₂Al phase in the Al-Ag system was used as the reference system and its misfit was controlled by ternary additions of Mg and Cu. The addition of 0.S1 at% Mg was found to increase the misfit from 0.8% for the binary to 1.11%. Cu additions on the other hand, reduced the misfit by 0.38% for Cu concentrations up to 0.51 at%. Electron probe microanalysis showed that the Mg atoms preferentially partition to the 7 phase whereas Cu atoms partition equally between the precipitate and matrix phases.
Direct transmission election rnicroscope observations were made on the interface structure in both the equilibrated state and during precipitate dissolution. The interface structure in the ternary Mg alloy consisted of a hexagonal network of partial dislocations which essentially remained the same before and during dissolution. A single array of a/2<110> dislocations was observed in the binary and ternary Cu systems prior to dissolution. This unit array transformed to a stable hexagonal network structure having the equilibrium spacing at the onset of dissolution and remained throughout the period of dissolution.
The thinning and shortening kinetics of the precipitate plates were at least five times slower than the rates for volume diffusion control in all three systems. This interfacial inhibition has further been confirmed by the consistent fall below equilibrium values of the interface concentration as determined from electron probe microanalysis. This suggests the operation of a ledge migration mechanism. A mechanism of acquiring ledge/dislocations at the interface is used as a basis to correlate the
observed kinetics with misfit and ledge migration at the precipitate-matrix interphase. The
mechanism involves co-ordinated motion of sets of dislocations in the network which rids the surface of the highest steps thereby accomplishing dissolution.Applied Science, Faculty of
Materials Engineering, Department of
Graduate
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Kim, Hee Jae. "The role of B[superscript]+ and N[superscript]+[subscript 2] ion implantation in the corrosion behavior of high purity iron and 44OC stainless steel." Diss., Georgia Institute of Technology, 1985. http://hdl.handle.net/1853/16482.
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Crudden, D. J. "Alloys-by-design : applications to polycrystalline nickel superalloys for turbine disc applications." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:b60e1854-cae4-4dd3-8d6f-cec1351e4c17.
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The nickel-based superalloys have been a key enabler to the development of modern gas turbine engines. Since their introduction the chemical complexity of these alloys has increased significantly, with current generation nickel-based superalloys usually containing over 10 different elements. It is this combination of alloying additions that is responsible for the superior high temperature properties these alloys exhibit. Traditionally, alloy design has invoked considerable use of trial-and-error based approaches involving costly and exhaustive processing backed up by empirical property testing. In this work a computational materials design approach is developed. This method links physically-faithful composition-dependent models with thermodynamic calculations to understand material behaviour. By doing this it is possible to consider large compositional design spaces and isolate alloys expected to have optimal performance for specific applications. The scope of this research has been to apply the computational model to the design of a polycrystalline nickel-based superalloy for turbine disc applications in next generation jet engines. The design trade-offs encountered when developing the new alloy are highlighted. Alloy compositions which are predicted to be optimal for turbine disc applications are isolated. These alloys have been manufactured using a scaled down version of the commercial production method. The newly manufactured alloys have been characterised using microstructural evaluation, mechanical testing and corrosion testing. The experimental results have been compared with modelling predictions in order to determine the capability of the computational approach.
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Mirrezaie, S. R. "Some aspects of the corrosion of Admiralty Brass in saline environment, studies by physical and electrochemical techniques." Thesis, Brunel University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.332445.
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Rigas, Konstantinos. "Thermal Physical Properties of Söderberg Electrode Material." Thesis, KTH, Materialvetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-259191.
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Söderberg electrodes take part in the production of ferroalloys, copper, nickel, platinum, and calcium carbide. They are involved in a continuous and with low costs operation. The study of such electrodes is essential, since research and new findings will provide us with vital information regarding the operation of such furnaces leading to a more efficient production. Therefore, the study of Söderberg electrodes materials characteristics is of great importance. The current work refers to the thermal properties of Söderberg electrode paste by focusing on the thermal conductivity coefficient from room temperature up to 800 °C with the Transient Plane Source (TPS) method applied to an electrode paste material with softening point at 65°C. Another electrode paste with higher softening point at 90 °C and an already baked material are studied to some extent. The study gives significant results for the thermal conductivity coefficient for all the investigated cases. Results indicate variation of coefficients regarding the phase evolved during heating at different temperatures. In principle, thermal conductivity of the green paste with low softening point decreases until 400°C and increases after the baking point which is found in between 400-500°C. A few measurements for the green paste with higher softening point indicate the same trend. For the case of the fully baked electrode, thermal conductivity seems to keep an increasing trend according to temperature increase. On the two last mentioned materials, more experimental work will be conducted in future.Söderberg-elektroder används till produktionen av ferrolegeringar, koppar, nickel, platina och kalciumkarbider. De är involverade i kontinuerliga och lågkostnadsoperationer. Studien av sådana elektroder är väsentlig eftersom forskning och nya fynd kommer att ge oss viktig information om driften av sådana ugnar vilket leder till en effektivare produktion. Därför är studien av Söderberg-elektrodens materialegenskaper av stor betydelse. Det nuvarande arbetet refererar till de termiska egenskaperna hos Söderberg-elektrodpastan genom att fokusera på den termiska konduktivitetskoefficienten från rumstemperatur upp till 800°C med den TPS-metoden (Transient Plane Source) tillämpad på ett elektrodpasta-material med en mjukningspunkt vid 65°C. En annan elektrodpasta med en högre mjukningspunkt vid 90°C samt ett redan bakat material studeras även till viss del. Studien ger signifikanta resultat för värmeledningsförmågan för alla undersökta fall. Resultaten indikerar på variationer av koefficienterna gällande fasen som utvecklas under uppvärmning vid olika temperaturer. I stort sett minskar värmeledningsförmågan hos den gröna pastan med låg mjukningspunkt upp till 400°C och ökar efter bakningspunkten som finns mellan 400-500°C. Några mätningar för den gröna pastan med en högre mjukningspunkt visar samma trend. När det gäller den helt bakade elektroden verkar värmdeledningsförmågan hålla en ökande trend beroende på temeperaturökningen. På de två sistnämnda materialen kommer mer experimentellt arbete att genomföras i framtiden.
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Jones, Stephen John. "Modelling inclusion potency and simultaneous transformation kinetics in steels." Thesis, University of Cambridge, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245152.
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Wessman, Andrew E. "Physical Metallurgy of Rene 65, a Next-Generation Cast and Wrought Nickel Superalloy for use in Aero Engine Components." University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1467126769.
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Rubal, Melissa Joanne. "Physical Simulation of Friction Stir Processed TI-5Al-1Sn-1Zr-1V-0.8Mo." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1243884648.
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Raj, Sanjay. "Significance of Activation Energy in Process Metallurgy." Thesis, 2013. http://ethesis.nitrkl.ac.in/5258/1/211MM1366.pdf.
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A study of thermal behaviour, thermal degradation kinetics, and effect of composition on flow characterisation of blast furnace slag is important to Understanding the flow characteristics of blast furnace (B/F) slag. It is an important parameter for efficiency/productivity of a blast furnace. In the present study flow characteristics of five different B/F slag (C/S: 1.04, 1.192, 1.107, 1.101, and 1.189) were investigated. This study was predominantly based on the estimation of activation energy. The activation energy was estimated using two methods: differential scanning calorimetry (DSC) and High temperature viscometer. DSC of different slag were measured at 30-1300oC @ 2o, 4o, 6o, 8o and 10oC/min. Activation energy was estimated from such DSC plots using Kissinger and Ozawa methods. It was observed that activation energy is largely dependent on C/S ratio of B/F Slag – The activation energy decreases with increase in C/S ratio. The flow characteristics of different B/F slag were also investigated by high temperature heating microscope, X-ray diffraction (XRD) and scanning electron microscope (SEM). The estimated IDT (initial deformation temperature), ST (softening temperature), HT (hemispherical temperature) and FT (fusion temperature) of different B/F slag was shown in table. Phase analysis of XRD and SEM micrographs support the results of flow characteristics measured by heating microscope.
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Das, Abhijit Kumar. "Dissimilar Joining of Metals by Powder Metallurgy Route." Thesis, 2015. http://ethesis.nitrkl.ac.in/6788/1/Dissimilar_Das_2015.pdf.
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Dissimilar metal joints have a wide range of applications in electronic connectors, due to its physical and mechanical properties. In the present work powder brazing is chosen as a tool for joining of Cu-SS, Cu-Fe, and Cu-Ni. Powder brazing of dissimilar metals has advantages over conventional joining techniques which does not involve melting of the base metal and thus avoids the problems associated with, variation in thermo-physical properties and leads to formation of high amount of undesirable compounds (high intermetallic layer at the joint interface) as a result high joint strength cannot be achieved, an able solutions to produce this type of joints has been developed. In the present work three different types of powder are chosen for brazing, Copper (Cu)-Stainless Steel (SS), Copper-Iron (Fe), Copper-Nickel (Ni) powders. Cu weight (2 gram), stainless steel powder (2 gram), iron powder (2 gram), and Nickel powder (2 gram), then the specimen were compacted with varying loads (4, 5, and 6 tonne), the compacts were in the shape of cylinders. The compacts were sintered at 900 °c in argon atmosphere with a heating rate of (10 k/min), the specimens were cross sectioned using abrasive cutting machine, mounted and polished for macroscopic and microscopic observation. The mounted specimens were polished with emery paper of 1/0, 2/0, 3/0, and 4/0 and were subjected to chemical etching using nital solution. To study macro and microstructures of the specimen optical and scanning electron microscope was used. Form the macrostructures it was observed that there is no presence of cracks in all the joints. It was observed that with the increases in compaction load there is a better bonding between the joints. Microstructures did not show any presence of Intermetallics. Form the hardness data it was confirmed that there is a presence of Intermetallics due to marginal variation in the hardness at the interface in all the cases. From the compression test it was observed that with the Cu-Ni has shown improved strength compared to Cu-SS and Cu-Fe. At higher compaction loads the specimens has shown higher strength in the all the cases (Cu-SS Cu-Fe, Cu-Ni) may be due to better bonding.
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Tung, Hai-ruei, and 童海瑞. "To Study the Effect of Physical Metallurgy Processes for Natural Quartz Refining." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/72703772648307398813.
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碩士大葉大學
機械與自動化工程學系
100
This research is aimed at the internal impurities removal of nature quartz from different areas. According to the forming conditions are not alike, the ingredients, distribution, and content of metal impurities are also different. If one can use a simple process to purify the quartz and still maintain the α-quartz crystal structure. It is believed that many practical applications for the solar energy and photoelectric industries will be achieved. First, the natural quartz should be crushed, sieved, magnetic separated, acidic leaching, washing and dried to be the experimental material. Following treated with low temperature water quenching process to promote the cracking along the grain boundary which due to the residual stress of quenching. Since the grain boundary cracks created and impurities exposed, the process of acidic leaching together with ultrasonic cleaning was applied. If the effect of acidic leaching not remarkable enough, still other purification methods can be proceed which included frequency conversion ultrasonic cleaning, low temperature high pressure (hydrothermal), high temperature negative pressure or high temperature high vacuum processes. From experimental results shown that, the best purified processes are after 600℃ water quenching, followed by hydrothermal treatment mixed with the hydrochloric acid and hydrofluoric acid in the ratio of 4:2. The outcome data showed that the impurity elimination rate of De-hua quartz powder achieved 76%, respectively. Even the high crystallinity and perfect crystal structure Sri Lanka quartz powder could also achieve 31% elimination rate. Comparing the purity of purified De-hua quartz powder with the standard of American UNIMIN highest solar grade powder, found that almost all metal impurities and total amount impurity have conformed the standard except the sodium content. Therefore, we believed that De-hua powder should be satisfied the needs of manufacturing the poly silicon quartz crucible, even fitting the requirement of outer layer quartz powder for single silicon quartz crucible for solar and/or semiconductor industries.
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Mishra, Tanvi. "Joining of Brass/Copper/Nickel with Stainless Steel by Powder Metallurgy Process." Thesis, 2016. http://ethesis.nitrkl.ac.in/9322/1/2016_MT_TMishra.pdf.
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Joining of dissimilar material is very attractive for many applications because of special performance requirements of materials in different areas like light-weight automotivebstructures, improving methods for energynproduction, creating next generation medical products and consumerndevices, and numerous other manufacturingnand industrial uses. Joining dissimilar materials by conventional welding processes have too many issues. One major problem is the direct change in properties ofjbase metals at the welding interface diminishes the quality of joints. In this joining method, two different metals/alloys in powder form are joined by the mechanism of plastic flow of the powder particles and diffusion of interface atoms using powder metallurgy process. The process was started with the blending of 304L Stainless Steel powder in a Ball mill. Then compaction was carried out by pouring 1gm of milled stainless steel (SS) powder and 1gm of copper powder into the die cavity and applying varying load (4 and 5 ton) by the mechanical press. By using same process Brass (1 gm) and Nickel (1 gm) powders were compacted with Stainless Steel (1 gm) powder at 4 and 5 ton load. The compacts were in the shape of solid round disc. After compaction compacts were subjected to the sintering process. This process involved the heating of compacts in Tubular Furnace (using argon atmosphere) below the melting point temperature of both the metals. Cu-SS and Ni-SS were sintered at 1000°C and Brass-SS was at 800°C with a heating rate of 10 k/min, and holding time was 2 hours. The sintered specimens were cross-sectioned by using the hand saw and then mounted and polished for macroscopic and microscopic observation. To study macro and microstructures of the specimen optical microscope and scanning electron microscope (SEM) were used. From the microstructure, it was observed that there is no presence of cracks in all the joints and even at higher magnification there is no appearance of intermetallic in the microstructures. Vickers micro hardness test showed that the increase in compaction load there was a better bonding between the joints. From the compression test, it was observed that Ni-SS and Cu-SS joint have shown improved strength compared to BrassSS.
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Chatterjee, Aniruddha, and Biswaranjan Dash. "Modeling of Phase Transformation Kinetics of Plain Carbon Steel." Thesis, 2009. http://ethesis.nitrkl.ac.in/283/1/CHIKU1.pdf.
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A mathematical model have been generated which incorporates the concept of isothermal/isokinetic steps in close association with the cooling curve to predict the transformation kinetics under continuous cooling conditions. Transformation kinetics under actual cooling conditions was predicted by the dilatometric analysis of the 1080 steel samples. The continuous cooling experiments were conducted for cooling rates of 5, 10, 15, 200 K/min to determine the time and temperature for start and end of pearlitic transformation respectively. The isothermal transformation data was also incorporated in the mathematical model to predict the continuous cooling transformation kinetics. The results of the mathematical model agree closely and in a similar manner with the measurements made at the four cooling rates.
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Banerjee, Abhishek, and Sumit Kumar Dhal. "Effect Of Strain Ageing In Welded And Non Welded Low Carbon Steel." Thesis, 2010. http://ethesis.nitrkl.ac.in/1837/1/Banerjee.pdf.
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Low carbon steels are susceptible to strain ageing as a result of which there is an increase in yield strength at the cost of ductility. These steels are used for structural applications, in which welding is used as a method of joining. There are certain regions away from the weldment which pass through the temperature range of 80 to 2500c during cooling after welding. Since in many of the structures like ship building these steels are welded in deformed condition thus the above said regions are subjected to straining and ageing, thus leading to strain ageing.
In the present study an attempt has been made to study the effect of strain ageing in welded low carbon steel and the results are compared with those obtained after strain ageing of the same steel in the non welded condition. The parameters used were : (1) % The extent of pre-strain of pre-strain used was 6 ± 2 %.(2)The temperature of ageing used was 150 ±300c.(3)The time of ageing used was 4 ± 2 hrs. Using the method of Statistical Design Of Experiments the results were analysed to develop regression equations for welded as well as non welded steels. The equations developed are shown in eqn(1) and eqn(2) respectively.
For non welded: ΔY = 24.04 - 2.18X1 + 4.9 X2 + 1.4 X3 – 0.03X1X2 – 0.018X1X3 + 35X2X3 - 0.28X1X2X3
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Bhattacharjee, Arjit, and Sagar Ranjan Pradhan. "Estimation of stress intensity factor for corrosive environment." Thesis, 2010. http://ethesis.nitrkl.ac.in/1843/1/e_thesis_submission_arijit.pdf.
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Corrosion fatigue refers to the damage and failure of material under the combined action of cyclic stresses and corrosive environment, which affect the life of fatigue critical structures, such as, aero structures, submarine hulls, offshore structures etc. Several surveys have shown that 20-40 % of all engineering failures are due to corrosion fatigue [1]. The corrosive environment may be considered as a condition of enhanced crack growth rate (under constant stress intensity factor) or decrease in net ΔK to maintain the same crack growth rate. In the present investigation an attempt has been made to develop a model to correlate net ΔK with crack length and frequency. The developed model was validated using experimental data generated for 7475-T7351 alloy in aqueous solution of 3.5% NaCl. It is also noticed that the frequency significantly does affect the crack growth rate (constant ΔK) and the maximum crack growth rate is usually achieved at an intermediate frequency.
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Tamuli, Kausik, and Ayaz Khan. "Effect of copper on the austempering behaviour of spheroidal graphite iron." Thesis, 2011. http://ethesis.nitrkl.ac.in/2172/1/report.pdf.
Full textAbstract:
Two types of spheroidal graphite cast iron samples, one with Cu and other without Cu were austempered at four different temperatures. The austempering temperatures were 250 ˚C, 300 ˚C, 350˚C, 400˚C. The main objective of the project was to develop the physical properties and morphology of the microstructures by austempering process. The tensile strength, yield strength, ductility, hardness and morphology of microstructure were studied after austempering. The effects of Cu on graphite nodule count, nodularity and pearlite percentage were observed. Samples with Cu showed higher values of tensile strength, yield strength, hardness but lower values of ductility as compared to samples without Cu. The effect of Cu on the formation of nodular graphite is not completely understood and much further work remains to be done. Both the types of irons have good nodular structure. Iron without Cu had a matrix of 95% ferrite and 5% pearlite. Iron with Cu % (0.42%) had about 50% ferrite and 50% pearlite as determined by using image analyzer. Thus offering all the production advantages of a conventional ductile iron casting, subsequently it is subjected to the austempering process to produce mechanical properties that are superior to conventional ductile iron.
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Mohanty, Jyotiranjan. "Fatigue Life Prediction Under Constant Amplitude and Interspersed Mode-I and Mixed-Mode (I and II) Overload using An Exponential Model." Thesis, 2009. http://ethesis.nitrkl.ac.in/2802/1/Jyoti_Thesis.pdf.
Full textAbstract:
Fatigue performance of structures is greatly affected by the presence of stress raisers such as fastener holes, manufacturing errors, corrosion pits, and maintenance damage which serve as nucleation sites for fatigue cracking. During service, sub-critical cracks nucleate from these sites and grow till catastrophic failure takes place when the crack length reaches a critical dimension. A structure can not be retired from service simply on detecting a fatigue crack. Hence, proper evaluation of fatigue crack propagation and residual life prediction of structures (aircraft, ship, railways, bridges, gas and oil transmission pipelines, etc.) are important to ensure the public safety, environmental protection, and economical consideration.
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Dhal, Jyoti Prakash. "Strengthening of SS316LN for Development of Superconductor Jacket." Thesis, 2011. http://ethesis.nitrkl.ac.in/2863/1/print_copy_of_J_P_Dhal.pdf.
Full textAbstract:
In recent years SS316LN stainless steel is preferred for use as a jacket material for Nb3Sn strands/wires. This superconductor is used in ITER (International Thermonuclear Experimental Reactor), a current driven plasma experiment that sets a milestone towards the demonstration of fusion reaction as a source of energy for future. In Indian scenarios, IPR (Institute for Plasma Research) is currently attempting to fabricate fusion grade Nb3Sn strands and cables for such purposes. So far, the Jacket material development and characterisation for Nb3Sn CICC (Cable-In-Conduit-Conductor) has been attempted at IMMT, Bhubaneswar. In my project work micro-alloyed SS316LN is prepared in a vacuum induction melting furnace; Niobium and molybdenum in their ferroalloy stage are considered as alloying element. These micro-alloyed steels are then subjected to cold rolling and heat treatment to minimize stress and defects in cast ingots. These micro-alloyed steels are expected to improved mechanical properties, compared to pure SS316LN, at liquid Helium temperature (i.e. 4K).
The various properties of the processed steel are examined using XRD, SEM and optical Microscopy. Chemical test such as OES is carried out to know the chemical composition of the micro-alloyed samples and for comparison with pure SS316LN. Similarly mechanical tests such as tensile and hardness tests are done to evaluate UTS, YS and Percentage elongation etc. for both as cast and heat treated samples. From this study it is found that, the Nb/Mo micro-alloyed steels are more suitable for used as jacket material for Nb3Sn superconductor strands to be used at cryogenic temperature.
Keywords: strengthening; micro-alloying; jacket material; CICC superconductor.
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Sarkar, Arindam, and Swayambhu Panda. "A development study of Microalloyed steel (HSLA) through experimental exploration." Thesis, 2012. http://ethesis.nitrkl.ac.in/3267/1/A_development_study_of_microalloyed_(HSLA)_steel_through_experimental_exploration-(108MM051)__%26_(108MM052).pdf.
Full textAbstract:
HSLA steel is indispensable to the development of modern and future civilisations. The selection of optimum solutionizing temperature range for microalloyed steel grades is of utmost importance as it can significantly reduce energy consumption. Reheating studies were carried out on two different micro-alloyed steel grades (strip samples) containing Niobium. The reheating temperature range and the effect of Niobium content on the final properties of the steel were established by performing a series of quench and temper experiments, followed by hardness testing. A different set of samples (of the same grades) were subjected to heating in a controlled atmosphere (Nitrogen atmosphere) to mark the differences as compared to heating in open (air) atmosphere. Hardness variation across the strip width was also tested. Microstructural analysis was done using SEM and EDX for further investigation of the results obtained. For both grades (and for both cases of heating in open and nitrogen atmosphere), hardness increased with an increase in solutionizing temperature. Also, at a particular solutionizing temperature, the hardness value was higher for the grade containing greater niobium content. This effect can be attributed to the increasing fraction of Niobium that dissolves into the solution (matrix) with increasing solutionizing temperature. However, after a particular temperature range, increasing the solutionizing temperature does not significantly increase the hardness, indicating the saturation of Nb levels in the solution.
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Prusty, Dibyaranjan, and Hitaindra Kumar Pradhan. "An investigation on texture-property correlation in cold-rolled non-oriented silicon steel." Thesis, 2012. http://ethesis.nitrkl.ac.in/3256/1/THESIS_MM07%2CMM41.pdf.
Full textAbstract:
Soft magnetic materials like cold rolled non-oriented (CRNO) steels are used in electrical appliances like motors, generators small transformer cores due to its superior magnetic permeability and low watt loss and less magnetic anisotropy signifying uniform magnetic properties in all directions. The application of CRNO steels demands uniform property in all angular directions. Keeping this in mind the objective of the present study is to find out the textural and property change in all angular directions of CRNO steel sheets and correlate texture-property. CRNO steel sheets of different silicon percentages (1.4%, 1.52%, 1.88%, and 2%) were observed in the present study. Four different sets of samples were made from the CRNO sheets: (1) samples along rolling direction, (2) samples at 30° to the rolling direction, (3) samples at 60° to the rolling direction and (4) samples at 90° to the rolling direction. Then the textural, electrical and magnetic properties were investigated using standard techniques. X-ray diffraction (XRD) and electron back scattered diffraction (EBSD) were used for bulk- and micro-texture measurements respectively. While four-probe method was used for electrical resistivity and pulse field hysteresis loop tracer was used for magnetic
property measurements. The results showed different texture and magnetic properties in all the CRNO samples.
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Dhal, Satyanarayan, and Raja Yadlapalli. "Effect of size and strain rate on deformation behaviour of Cu50Zr50 metallic glass: A molecular dynamics simulation study." Thesis, 2012. http://ethesis.nitrkl.ac.in/3349/1/final_thesis.pdf.
Full textAbstract:
Metallic glasses or amorphous metals have attracted considerable attention due to their unique properties and have been evolved as a potential field of research in recent years. The recent discovery of new glass-forming compositions makes it possible to produce metallic glasses in bulk shapes. Bulk metallic glasses provides a promising future to revolutionize the field of structural materials with combinations of strength, elastic limit, toughness, wear resistance and corrosion resistance. Some of their superior properties over crystalline metals have made them a versatile engineering material for many commercial applications now-a-days. Since the fabrication of metallic glasses require high cooling rates and sometimes practically impossible in laboratory conditions, so computational approaches are extensively used to explore various properties and behaviour of metallic glasses.
This project work presents a molecular dynamics simulation study on deformation behaviour of Cu50Zr50 metallic glass where the effect of parameters like sample-size and strain rate on the tensile deformation behaviour have been thoroughly studied. Computational methods to create alloy models, subsequent quenching and further tensile deformation have been mentioned. Stress-strain plots were drawn at same strain rate for different sizes of alloy models and at different strain rates for a particular size. Reasons for getting different stress-stress curves for different conditions have also been discussed.
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Kindo, Ajit Kumar, and Rajesh Goel. "Optimization of heat treatment of steel developed for turbine shafts." Thesis, 2012. http://ethesis.nitrkl.ac.in/3450/1/THESIS(108MM015%2C_108MM022).pdf.
Full textAbstract:
Turbine shafts are basically used in steam turbine, hydro turbine and wind turbines. These turbine shafts require very stringent properties. Generally high yield strength, tensile strength and percentage elongation are required along with high impact values at the same time. In addition, the material should exhibit good high temperature properties such as creep, elevated temperature strength and thermal stability. Practically the turbine shafts used are very massive in size. Hence, the coefficient of thermal expansion should be small so as to maintain a minimum temperature gradient between the core and the surface of turbine shafts. If the temperature gradient crosses a certain limit, it may lead to generation of crack inside the structure.
As mentioned, we require high tensile properties along with good impact strength for proper application. But it is generally observed that these two properties are inversely related to each other i.e. the efforts to increase the tensile strength of materials results in decrease in impact strength and vice versa. Therefore, one has to judiciously select the heat treatment parameters so as to maintain a good combination of these properties.
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Garg, Bhuvnesh, and Pankaj Kumar. "Fatigue behavior of aluminium alloy." Thesis, 2007. http://ethesis.nitrkl.ac.in/4190/1/%E2%80%9CFATIGUE_BEHAVIOUR_OF_ALUMINIUM_ALLOY.pdf.
Full textAbstract:
The present project deals with study of fatigue life of Aluminium alloy treated at two different temperatures. This temperature is above and below the recrystallisation temperature of Aluminium alloy. The specimen is commercially available Aluminium alloy which is annealed, tensile testing is done and then fatigue life of the specimen is determined. Failure of the specimen at different stress applied is determined and number of cycles to failure is noted. Fatigue has become progressively more prevalent as technology has developed a greater amount of equipment, such as automobiles, aircraft, compressors, pumps, turbines, etc., subject to repeated loading and vibration. A fatigue failure can usually be recognized from the appearance of the fracture surface, which shows a smooth region, due to the rubbing action. In our experiment we have done the annealing of aluminum alloy above and below recrystallisation temperature in the recovery range. The tensile testing of the specimen was done in INSTRON 1195. The results obtained from this test says that yield strength of the aluminum alloy was found to be more below recrystallisation temperature then that above recrystallisation temperature. The failure of the specimen here occurs at a very large number of cycles. This of the order of 10 5.this number of cycles decreases with an increase in the applied stress. As the load increases the failure of the specimen would occur at a less number of cycles. This alloy used fails at a large number of cycles. Also no endurance limit is obtained here. So for use of this alloy large number of cycles is required and also a lower yield stress. This aluminum alloy can be used for a large number of uses. Aircraft application, gas pipelines, oil tanks, pistons, etc.
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Panda, Sabitra Subhadarsan, and Pradipta Kumar Das. "Fiber reinforced polymer composites characterization by differential scanning calorimeter." Thesis, 2007. http://ethesis.nitrkl.ac.in/4212/1/Fiber_Reinforced_Polymer_Composites_Characterization_by_Differential_Scanning_Calorimeter.pdf.
Full textAbstract:
The conventional materials are nowadays not sufficient to cater to the variety of uses and exposure to various environments that may take place while they are put into use. Hence this leads to the development of composites, which nearly suffice the above two conditions. But they are always prone to detoriation and degradation of properties due to their extreme affinity for moisture absorption. Many complex reactions occur at the fibermatrix interface due to moisture absorption, but very little information is available regarding the deviation in physical and chemical behavior at the interface due to this. The present work focuses on the physical changes occurring at the fiber-matrix interface. In our case, the samples were divided into three parts. One was kept as dry sample; the others were hygrothermally aged for 50 hours and 100 hours respectively at 50o C and 95% humidity. Now a comparative study of all the three samples was done near the interface. The DSC technique was carried out to study the physical changes or deviation of the Glass transition temperature of the composite. From the nature of the curve obtained from the DSC measurements, we can infer about how the Glass transition temperature varies with the heat flow, and how it varies for different samples with different hygrothermal treatment. From these data, the changes occurring at the interface can be known.
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G, Suhas, Tusara Kanta Nath, and Subrat Das. "Property development in S.G iron by heat treatment." Thesis, 2007. http://ethesis.nitrkl.ac.in/4243/1/PROPERTY_DEVELOPMENT_IN_S.G_IRON.pdf.
Full textAbstract:
Cast iron is an alloy of iron containing more than 2% carbon as an alloying element. It has almost no ductility and must be formed by casting. ductile iron structure is developed from the melt of cast iron. The presence of Si in higher amount promote the graphitizarion inhibiting carbon to form carbides with carbide forming elements present the carbon forms into spheres when Ce, Mg, are added to the melt of iron with very low sulphur content having this special microstructure containing graphite in nodular form gives ductile irin thus the ductility and toughness superior to that of any cast iron and steel structure finding numerous success in industrial application however heat treatment is a valuable and versatile too for extending both the consistency and range of properties of ductile iron casting beyond the limits of those produced in as-cast condiotion. Thus to fully utilize the potentioal of ductile iron castings, the designer should be aware of wide range of heat treatment available for ductile irin and its response to this heat treatment. Although ductile iron and steel are superficially similar metallurgically, the high carbon and silicon level in ductile iron results in important differences in their respionses to heat treatment. The high carbon leels increase hardenibility, permitting heavier sections to be heat treated with lower requirements for expensive alloying or severe quenching media also may cause, quench cracking due to the formation of high C martensite. This undesireable phenomena maje the control of composition, austenitising temperature and quenching conditions more critical in ductile iron. Since the formation of martensite is accompanied byu internal stresses, tempering is necessary in order to relieve the internal stresses, decreases the amount of retained austenite and reduces the probability of cracking. Austempering is a critical heat treating process in which austenite transforms isothermally to lower bainite rather than martensite and thus objectively reduces distortion and cracks. It is possible to achieve much larger ranges of tensile strength, ductility with toughness by adopting austempering, heat treatment process of ductile iron.
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Kishor, Rajat. "Assessment of Density and Character of Dislocations in Cyclic Loaded Stainless Steel Using X-ray Diffraction Profile Analysis." Thesis, 2014. http://ethesis.nitrkl.ac.in/5609/1/212MM1415.pdf.
Full textAbstract:
Asymmetric stress-controlled fatigue i.e., ratcheting behaviour of a non-conventional stainless steel X12CrMnNiN17-7-5 has been investigated with varying mean stresses, stress amplitudes and number of cycles at room temperature using a servo hydraulic universal testing machine. The X-ray diffraction profile analysis using the modified Williamson–Hall equation has been carried out in order to estimate the dislocation densities in the specimens subjected to ratcheting deformation. Increase in strain accumulation has been explained by increase in dislocation densities in the ratcheted specimens and a correlation between the strain produced by ratcheting deformation and the estimated dislocation density has been established.
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Sarangi, Rama Chandra. "A Study of Processing of Indium Doped Semiconductor Material." Thesis, 2013. http://ethesis.nitrkl.ac.in/4631/1/211MM1369.pdf.
Full textAbstract:
Indium- doped Silicon is being investigated as an extrinsic photoconductor material for use in the 3 to 5 µm infrared region. The low indium concentration obtained by standard growth methods and presence of a shallower defect level associated with the indium. The concentration of indium in float zone grown crystals is generally even lower than this because of the low segregation co-efficient of indium. A shallower defect Centre associated with indium and labelled as indium. It is observed that in Hall co-efficient measurements at energy of about 0.11eV. Solution growth techniques such as gradient –transport solution growth and LPE have been used to grow III – V compound. The use of temperature – gradient zone melting as a means of producing large area p – n junctions in silicon. An important feature of this solution growth procedure is that the crystals are grown the melting point of silicon.so the retrograde solubility of the impurities can be used to obtain very heavily doped crystals. In the present work Indium is doped on silicon metal inside a micro-oven at the temperature of 2000C.Different samples are kept inside the micro-oven for different time period. After that XRD,SEM and V-I characteristics have been done, then voltage drop is calculated and different peaks have come and changes in micro structure have been found.
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Sampark, P., and Goutam Kumar Majhi. "Deformation Induced Phase Transformation of 304L Stainless Steel and its Structural Characterization." Thesis, 2013. http://ethesis.nitrkl.ac.in/4788/1/109MM0447.pdf.
Full textAbstract:
This report aims to examine deformation induced phase transformation in 304L stainless steel up on compressive loading at room temperature of 300K. For this, compression tests were carried out using specimens of varying length to diameter ratios. To avoid effects of any friction, teflon tapes were use at the specimen platen interfaces. The results indicate that homogenous deformation takes place up to 15% of total compressive engineering strain. X-ray diffraction and scanning electron microscopic studies indicate that metastable austenite transforms to martensite due to compressive loading. “The volume fraction of martensite increases with increase in percentage of deformation.” Post deformation hardness also increases monotonically. Nature of homogenous deformation also gets reduced due to prevailing friction at the interfaces. In the course of the study, the amounts of particular phase fractions have also been calculated from the integrated intensity of XRD results. The results are then correlated with the extent of deformation in the respective samples and the behavior is compared as-against tensile loading conditions.
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Nayak, Dillip kumar, and kumar Palai Rajesh. "To study the effect of strain rate on tensile properties and high cycle fatigue behaviour of if steel." Thesis, 2013. http://ethesis.nitrkl.ac.in/5054/1/109MM0483.pdf.
Full textAbstract:
Interstitial Free steel finds its application in automobile industries. Their extensive use in this industry is due to its excellent formability, weldability and toughness. These materials are usually exposed to various strain rates during service. In the present investigation an attempt has been made to study the effect of strain rate. And it has been found that as the strain rate of loading increases the strength of the material increases but the ductility decreases. Though enough information are available on the effect of low cycle fatigue on this type of material, however in many cases they are also exposed to high cycle loading condition. Therefore an attempt has been made to study the effect of high cycle fatigue with ómax close to the yield strength of the material. And a relation has been established between the stress ratio and the number of cycles to failure
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Sahoo, Sanjay Kumar, and Siddharth Pal. "Recrystallization Texture Development in CP-Titanium." Thesis, 2013. http://ethesis.nitrkl.ac.in/5319/1/109MM0487.pdf.
Full textAbstract:
Most of the structural components are subjected to annealing as a final forming operation for different applications. It is therefore very important to understand/know the texture development during annealing of a material. This will decide the mechanical property of the component. Annealing texture of cubic crystal system has been widely researched, but little work has been done for the hexagonal close-packing materials. In the present study recrystallization texture development in CP-titanium was investigated. CP-titanium plates were subjected to cold rolling of 90% reduction in thickness. The rolled samples were then subjected to isochronal annealing at 5000C, 6000C and 7000C for 30minutes to obtain the recrystallization temperature, determined by EBSD analysis. Final annealing was carried out at 600oC for different soaking time: 10sec, 20sec, 1min, 2min, 5min, 10min, 20min and 30min to establish the texture development during annealing. These annealed samples were subsequently characterized under XRD (X-ray Diffraction) for bulk texture measurement. The initial deformation texture i.e. (1 1 -2 4)<1 -1 0 0> got attenuated with time and development of new basal orientation i.e. (0 0 0 1)<1 -1 0 0> and non-basal orientations i.e. (2 1 -3 7)<1 -2- 1 0>, (3 1 -4 9)<2 -15 13 1> and (5 1 -6 15)<1 -5 4 0> were observed.
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Sahoo, Baidehish. "Recrystallization Texture development in CP-Titanium." Thesis, 2013. http://ethesis.nitrkl.ac.in/5320/1/211MM1367.pdf.
Full textAbstract:
Understanding of recrystallization texture, the objective of the present study, is very
important because most of the engineering components subjected to annealing as a final
forming operation before different applications. Such recrystallization texture is well
established in cubic materials compared to hexagonal materials. In the present study
recrystallization texture development in CP-titanium was investigated. CP-titanium grade-2
plates were subjected to cold rolling of 90% reduction in thickness. The rolled plates were
annealed at 700oC for 5hrs. Such annealed plates were then subjected to accumulative roll
bonding (ARB) for 6 passes. The ARB processed samples were then subjected to isochronal
annealing at 200oC, 300oC, 400oC, 500oC and 600oC for 1hr to obtain the recrystallization
temperature. Final annealing of the ARB processed samples was carried out at 600oC for
different soaking time: 5sec, 10sec, 20sec, 30sec, 60sec, 120sec, 300sec, 600sec, 1200sec,
1800sec and 3600secr, to establish the texture development during annealing. The annealed
samples were subsequently characterized under XRD (X-ray Diffraction) for bulk texture
measurement and EBSD (Electron backscattered diffraction) for micro-texture and
microstructural developments. Strengthening of (11-24)<31-4-1> orientation with increasing
annealing time was observed.
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Sahu, Lopamudra. "Ratcheting behavior of a non-conventional stainless steel and it's associated microstructural variations." Thesis, 2013. http://ethesis.nitrkl.ac.in/5339/1/211MM1368.pdf.
Full textAbstract:
The aim of this investigation is to study the influence of asymmetric cyclic loading on accumulation of plastic strain with attendant in-situ microstructural variations that occur during cyclic deformation of a non-conventional stainless steel. The phenomenon of plastic strain accumulation due to asymmetric cyclic loading is known as ratcheting. Stress-controlled cyclic loading experiments have been carried out at 300 K for constant mean stress levels with varying stress amplitudes and constant stress amplitudes with varying mean stress. These tests have been carried out by using a 100 KN servo-hydraulic INSTRON (model: 8500R) testing machine. Cyclic loading rate for stress control test is 50 Mpa/s. The stress, nominal strain and the actuator displacement data were continuously recorded during each test to acquire at least 200 data points per cycle. All fatigue tests have been done upto 50 and 100 number of cycles for further analysis. Transverse sections from the gauge portion of the ratcheted samples have been cut after the cyclic loading tests and were subjected to X-ray diffraction (XRD) analyses using Cu Ká radiation. Microstructural examinations have been done with the help of scanning electron microscope (SEM). In addition, ratcheted samples were investigated to assess any variation of their hardness values. The results highlight that the nature of strain accumulation is dependent on the combinations of means stress and stress amplitude. The results of post-ratcheting hardness tests indicate that there is considerable variation in hardness with number cycles. XRD results indicate that considerable amount of austenite transforms to martensite during ratcheting deformation and the amount of martensite varies with the combination of stresses. Increase in ratcheting strain with increase in mean stress or stress amplitude can be explained from increased plastic damage to the material as well as shifting of zone of plastic deformation.
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Mishra, R., and A. Dash. "An investigation on texture property correlation in annealed CP-Titanium." Thesis, 2014. http://ethesis.nitrkl.ac.in/5569/1/E-THESIS_38.pdf.
Full textAbstract:
Rapid industrial development and advances in the fields of engineering and related technologies during the last five decades have led to the extensive use of traditional metals and their alloy counterparts. Ti is one such metal which has gained popularity in the aerospace and defence related applications due to its wide range of mechanical properties like excellent specific strength , stiffness, corrosion and erosion resistance, fracture toughness and capability to withstand significant temperature variations. The present investigation is a step at correlating the crystallographic orientation and mechanical properties of commercially pure Ti (CP-Ti). Annealed CP-Ti specimens were prepared along the rolling direction, perpendicular to the rolling direction and 45o to the rolling direction. The specimens were then deformed to failure under uniaxial tension test in tensile test. Crystallographic textures of the specimens were measured before and after tensile deformation. Correlation of texture and mechanical properties was investigated. Subsequently, hardness of different grains/orientations of CP-Ti was measured through nano-indentation, grain average misorientation, elastic stiffness and Taylor factor measurements
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Dungdung, A. J., and R. K. Sethy. "Textural and magnetic properties of cross-rolled silicon steels." Thesis, 2014. http://ethesis.nitrkl.ac.in/5809/1/E-23.pdf.
Full textAbstract:
Silicon steels are widely used for their electrical applications in motors, generators, small transformer cores due to their high permeability, low core losses and their uniform magnetic properties in all directions of the material. The major processing steps involved for the production of silicon steels are hot rolling, cold rolling and annealing. The processing steps largely affect the texture of these steels which subsequently improves the electrical properties of these steels. The objective of the present study is to investigate the cross-rolling effect on texture development of silicon steels and its magnetic/electrical properties. X- ray Diffraction (XRD) method is carried out on the sample to understand the textural development. PC based Pulse Field Hysteresis Loop Tester is used to estimate the magnetic properties. It is observed that the steels have improved textural and magnetic properties.
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Behera, S. "Synthesis, characterization and mechanical properties of (Al, Cu)3Ti powder blend by mechanical alloying." Thesis, 2014. http://ethesis.nitrkl.ac.in/5822/1/E-33.pdf.
Full textAbstract:
In the present investigation, an attempt has been made to study the formation of intermetallic compound for Al70Cu22Ti8 alloy composition by mechanical alloying. Elemental powder of Al70Cu22Ti8(all in wt. %) composition was milled in a Fritsch pulverisette planetary mill for 50h under toluene. Powder of 1wt. % Y2O3 and 1wt. % TiO2 were added separately to the 50 h milled base alloy powder to study the effect of oxide dispersion. X-Ray diffraction shows the formation of AlCu, AlTi3, and Cu9Al4intermetallics compound formation after 50h of milling. There is a formation of Al2O3 for Y2O3 and TiO2 dispersed base alloy sintered at all temperatures. It has been observed that the rate of reduction of size is very fast up to 10h of milling and after that it is gradually decreases and remains constant after 10 h of milling. Particle size has been reduced from 45 ƒÝm to 6 ƒÝm after 50 hour of milling. DSC study shows the presence of small endothermic peak at 535C for formation of Al2Cu and two exothermic peaks at 701C and 850C for formation of other intermetallics like AlTi3, Cu9Al4andAlCu. A maximum of 81% theoretical density was obtained for the composite powder mixture sintered at 1100C for 1h. A maximum Vickers microhardness of 449, 649, 872HV were obtained for base alloy, Y2O3 and TiO2 dispersed alloy sintered at 1100C for 1h respectively. It was also found that TiO2 and Y2O3 dispersed base alloy have higher wear resistance than base alloy.
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Singh, S. K., and R. Bhengraj. "Study of Zn-Sn-Al solder alloys." Thesis, 2014. http://ethesis.nitrkl.ac.in/5893/1/E-80.pdf.
Full textAbstract:
In the electronic industry Pb-Sn solder is a very important material but Pb is toxic and has adverse effects on the environment and human beings. Due to the harmful effects of the Pb the use of the Pb-Sn solder alloys are being avoided and new Pb-free solder alloys are being used for electronic applications. The Sn – Zn – Al alloys are one of significant candidates in the proposal of alternative lead-free solders for high temperature soldering. Three Sn – Zn – Al alloys were prepared and studied experimentally. The micro-hardness and X-ray micro-analysis of the samples were conducted. The specimens were studied metallographically including SEM (BSE) in order to determine the composition and identification of individual phases. Melting point and significant temperatures of the alloys are found by DSC and TGA analysis. The diagram of the Al – Sn – Zn ternary system is given thermodynamically more precisely on the basis of our complex study. The fracture analysis wa also done with the help of FESEM. The basic difference between the eutectic solder and addition of Aluminium was observed. Economics of the processing of the solder was briefly discussed.
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Sahu, Bibhudatta. "Effect of notch geometry on the mechanical properties of pure copper using MD simulation." Thesis, 2014. http://ethesis.nitrkl.ac.in/6239/1/110MM0378-17.pdf.
Full textAbstract:
The aim of this investigation is to study the effect of various notch geometries on the tensile and compression behaviors of nano-scalecopper at various temperatures through simulations based on molecular dynamics. In view of this, first simulation boxes have been created comprising of cylindrical, square and v-notches. Simulations for tensile and compression deformations have been done for all un-notched and notched specimens at different temperatures (viz. 100 K, 200 K, 300 K, 400 K and 500 K). The results indicate that yield and tensile strength values decreases with increase in temperature for all notched and un-notched simulation boxes. Strength values increase with introduction of notches of all geometries as compared to the un-notched ones, at all temperatures.In contrast to the tensile strength, it is found that the compression strength of notched specimen decreases with introduction of notches at a particular temperature.The variation in strength is attributed to the formation of stress triaxiality around the tip of the notch and plastic constraint factor. The square notch is the highest contributor to increase the tensile strength. Overall, it can be stated that molecular dynamic simulation can be effectively used to study the deformation behaviour of notched specimens.
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Upadhyay, Supriya. "Low cycle fatigue and post fatigue tensile behavior of a non-conventional austenitic stainless steel." Thesis, 2014. http://ethesis.nitrkl.ac.in/6387/1/E-20.pdf.
Full textAbstract:
Traditionally, stainless steels find a wide range of applications, which include pipelines, automobiles, engine and gear parts etc. In many of these applications, structures and components go through fatigue loading ranging for low cycle to high cycle. ISO/TR 15510 X12CrMnNiN17-7-5 is a special grade of austenitic stainless steel, which is developed to conserve nickel and is used in automobile parts such as automotive trim, automobile wheel covers, flat conveyer chains, railroad passenger car bodies. The aim of this project is to explore the low cycle fatigue behaviour and its effect on the tensile properties of the abovementioned non-conventional stainless steel, which is unavailable in literature. Attempts have also been made to understand the microstructural variation due to deformation in the steel, as the structure is austenitic, hence metastable in nature. For these purposes a set of non-conventional austenitic stainless steel rods were annealed by soaking at 1000°C for one hour these were followed by water quenching prior to machining.The fatigue studies have been carried out at four different strain amplitudes (at ambient temperature) up to 100 cycles, which have been followed by tensile tests on the fatigued samples at constant crosshead speed of 1mm/minute. The low cycle fatigue results include that the steel undergoes cyclic softening behavior, which has also been reflected from the post-fatigue tensile results X-ray diffraction studies indicate that deformation induced phase transformation takes place in the steel due to combined effects of fatigue and tensile loading. The extent of phase transformation has been estimated and is correlated with the extent of deformation.
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Bishoyi, Bibhudutta. "Laser beam welding of commercially pure titanium sheets." Thesis, 2014. http://ethesis.nitrkl.ac.in/6398/1/E-5.pdf.
Full textAbstract:
In the present work, effect of process parameter such as laser power, welding speed, size of beam diameter on the microstructure and mechanical properties on laser beam welding of annealed commercially pure titanium (cp-ti) grade-2 is investigated.Titanium is preferred due to its wide applications in the field of automobile, marine, aerospace, power plant, structural etc. for its light weight, high specific strength, high corrosion resistance, having good mechanical properties at elevated temperature.Laser welding has more advantages over other normal fusion welding due to its low heat input, high cooling rate and high power density.it provides deeper and narrower weld bead results high welding efficiency and smaller heat affected zone leads to good mechanical property.The laser welding of cp-ti sheet of 1mm thickness was carried out by using a continuous wave (CW) CO2 laser at different operating conditions such as laser power at 2kW & 2.5kW, welding speed from 4m/min to 8m/min and laser intensity distribution by Gaussian Mode (0.18mm beam diameter at focus) and Donut Mode (0.36mm beam diameter at focus).Microstructure of weld size and fusion zone were examined by using optical microscope at different magnifications.Weld size was decreased with increasing welding speed and increased with increasing laser power and spot diameter.At low welding speed, elongated grains were observed in the weld interface. It also showed a sharp interface at large beam diameter (Donut mode). Measurement of micro-hardness was taken across the welding by using micro-hardness testing machine. The Vickers hardness increases from base material to centre of weld region. Tensile testing of the weld was carried out in a universal testing machine and it is observed that tensile strength of weld at different process parameters is approximately equal to the tensile strength of base metal.Comparative studies of process parameters on the laser welding of cp-ti were investigated.