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1
Morrissey, Francis H. J. "A study of fracture and segregation in corrosion resistant alloys : 316ss, Alloy 600 and Alloy 690". Thesis, University of Bristol, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284840.
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From, Malin, Johanna Ejerhed, Artin Fattah, Markus Lindén i Alex Karlstens. "Heat Resistant Steel Alloys : Atlas Copco". Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-256662.
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Atlas Copco is interested in investigating the friction in the top-hammer drilling tool threads thatcauses the steel to heat up, leading to a phase transformation and a softer steel in the threads. Theaim of this project is to find a steel alloy or surface finishing that will retain its hardness atelevated temperatures better than the presently used threads material. The solution is intended tobe used as a replacement material for the threads. The potential material is meant to combat thepremature breakdowns of the threads and thus minimizing the economical losses. To achieve ourproject goal, literature studies and an experimental parts were employed.Hardening methods are discussed thoroughly in the thesis, such as carbides/nitrides,precipitation, solid solution, grain size, and martensitic transformation. Alloying elements andtheir effects on steels properties were also discussed. C, Cr, Co, Mn, Mo, Ni, W, and V werefound to increase the steel's hardness at elevated temperature, high temperature strength andabrasion wear resistance.Nitration can be applied to most of the steels that Atlas Copco uses today, and will give a harder,and more wear resistant surface at elevated temperatures. A problem with nitration is that thenitrided layer is generally thinner than the martensitic hardening used today.Three tool steels samples (ASP 2030, ASP 2053 and ASP 2060) were acquired from Erasteel.These were used in the experimental part and compared to reference steels that Atlas Copcocurrently are using (R1-R6). The experiments were conducted in 400 and 600°C and the sampleswere tempered for 1, 10 and 100 hours before the hardness were measured with a Vickershardness test. The conclusion from the experiments was that ASP 2060 and ASP 2053 fromErasteel are the steels that have a much higher hardness at elevated temperature than the othersteels tested in the experiment. The results indicate that the tool steels will probably notexperience the same premature breakdown as the threads used today. R1 and ASP 2053 have thegreatest heat resistance.The suggested tool steels are all quite expensive, and to minimize the material needed only thethreads and not the rod can be in the new alloy. Lowering the cost could also be achieved byhardfacing where a layer of the new expensive alloy is welded onto a cheaper steel.
3
Sismanis, Panagiotis G. 1959. "The dissolution of niobium and zirconium in liquid steel". Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=28391.
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The dissolution rates of niobium and zirconium cylinders in liquid steel have been measured in a 'dynamic way', with the help of a data acquisition and process control facility. Two distinct periods were identified; the steel shell period and the free dissolution period.Lower bath superheats allowed a reaction to take place at the steel shell/niobium interface while higher superheats didn't; the intermetallic compounds Fe$ sb 2$Nb and Fe$ sb 2$Nb$ sb 3$ were identified as the reaction products. Niobium dissolved relatively slowly in liquid steel and its dissolution speed was increased under dynamic conditions (i.e., inductively stirred baths).
In the case of zirconium, an exothermic reaction occurred at the steel shell/zirconium interface and the intermetallics Fe$ sb 2$Zr and FeZr$ sb 2$ were identified as the reaction products. This reaction was triggered at 1220 K by the formation of a liquid Fe-Zr (76 at% Zr) eutectic. For the experimental conditions under which this study was performed, the hydrodynamic conditions of the steel baths did not seem to influence the dissolution rates of zirconium.
A simplified mathematical model was used in order to simulate the coupled heat and mass transfer phenomena which take place during the two periods.
4
Yu, Dawei. "Welding metallurgy and toughness improvement for mild and low-alloyed steel electroslag weldments /". Full text open access at:, 1988. http://content.ohsu.edu/u?/etd,164.
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Mavropoulos, L. T. "The synergistic effect of niobium and boron on recrystallization in hot worked austentite /". Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74031.
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Schroth, James Gregory. "Combined mode I - mode III fracture toughness of a high-strength low-alloy steel /". The Ohio State University, 1985. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487260859496482.
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Olajire, Kabiru Ayinde. "Machining of aerospace steel alloys with coated carbides". Thesis, Coventry University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301195.
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Harty, Brian Dudley. "Corrosion fatigue of engineering alloys in aqueous environments". Doctoral thesis, University of Cape Town, 1990. http://hdl.handle.net/11427/18215.
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A comparative study of the fatigue crack growth rate (FCGR) behaviour of five alloys in air and in aqueous environments has been performed. The alloys tested include: mild steel as a reference material, a corrosion resistant dual phase steel, 3CR12, a proprietary martensitic stainless steel, AISI 431, a newly developed 8% Cr martensitic steel, Alloy 825, and a newly developed corrosion-abrasion resistant metastable austenitic alloy, 1210. Tests were conducted in laboratory air, distilled water at rest potential, 500 ppm chloride solution at rest potential, 1000 ppm chloride solution at rest potential, and 1000 ppm chloride solution at -1200 m V see; solution temperatures were maintained at 25⁰ C. Crack growth rate tests were performed using sinusoidal loading at a load ratio R = 0.1, a frequency of 3Hz in the laboratory air, and a frequency of 1 Hz in the aqueous environments. At the completion of testing, fracture surfaces were studied using a scanning electron microscope. In air, the mild steel and 3CR12 display comparable rates of cracking and exhibit a greater resistance to fatigue crack propagation than the martensitic AISI 431 and Alloy 825; Alloy 825 shows the least resistance to fatigue crack propagation. The deformation induced transformation in 1210 gives this alloy the greatest resistance to fatigue crack propagation in air. Fatigue crack growth rates were all enhanced in the aqueous environments. The greatest overall rate of environmentally assisted cracking was shown by alloy 825 while the lowest was shown by the mild steel. Although the rate of cracking of 1210 in the aqueous environments was less than that of Alloy 825, 1210 was influenced the most by the aqueous environments. An environmentally assisted cracking index shows that the rate of fatigue crack propagation in 1210 is increased by 32 times in the 500 ppm chloride solution at low stress intensities. The fatigue crack growth rates of mild steel and AISI 431 were significantly influenced by the cathodically polarised conditions in the 1000 ppm chloride solution, compared to the rest potential conditions. In these cases hydrogen was seen to be evolved from the specimen surfaces. Changes in the fatigue crack growth rate behaviour were accompanied by changes in the fracture surface morphologies. The observed changes varied for each alloy and for each environment, and were manifest by the degree of intergranular cracking, cleavage, quasi cleavage, and increased coarseness of the transgranular cracking. The fracture surface morphologies are reported and discussed in detail. In general, the fracture surface morphologies could be directly related to the relative degrees of environmental influence on the rate of cracking; results are explained in terms of existing hypotheses. It is suggested that the environmentally assisted cracking of mild steel and AISI 431 at cathodic potentials in the 1000 ppm chloride solution could only be attributed to hydrogen assisted cracking. Similarly, it is suggested that the large crack growth rate acceleration of 1210 in the aqueous environments could also be attributed to hydrogen. The similar fracture surface morphologies observed on the other specimens after tests in the aqueous environments suggests-that hydrogen could be responsible for the environmentally assisted cracking of all the steels in aqueous environments.
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Hayes, Alethea M. "Compression behavior of linear cellular steel". Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/32857.
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Wong, Yat Khin. "A phenomenological and mechanistic study of fatigue under complex loading histories". University of Western Australia. School of Mechanical Engineering, 2003. http://theses.library.uwa.edu.au/adt-WU2003.0017.
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[Truncated abstract. Please see pdf format for complete text.] Over the years much work has been done on studying sequence effects under multilevel loading. Yet, the underlying fatigue mechanisms responsible for such interactions are not fully understood. The study of fatigue under complex loading histories begins by investigating strain interaction effects arising from simple 2-step loading sequences. Fatigue for all investigations were conducted under uniaxial push-pull mode in strain-control. Fatigue is traditionally classified as either low or high cycle fatigue (LCF and HCF respectively). The boundary for LCF and HCF is not well-defined even though the fatigue life of LCF is typically dominated by crack “initiation”, while for HCF, fatigue life is usually dominated by stable crack growth. The terms LCF and HCF, apart from referring to the low and high number of fatigue cycles required for failure, also bear little physical meaning in terms of describing the state of fatigue imposed. As a result, conventional definitions of the two distinct regimes of fatigue are challenged and a new method of classifying the boundary between the two regimes of fatigue is proposed. New definitions are proposed and the terms plastically dominant fatigue (PDF) and elastically dominant fatigue (EDF) are introduced as suitable replacements for LCF and HCF respectively. PDF refers to the condition of a material undergoing significant reverse plasticity during cyclic loading, while for EDF, minimal reverse plasticity is experienced. Systematic testing of three materials, 316 L stainless steel, 6061-T6 aluminium alloy and 4340 high strength steel, was performed to fully investigate the cycle ratio trends and “damage” accumulation behaviour which resulted from a variety of loading conditions. Results from this study were carried over to investigate more complex multilevel loading sequences and possible mechanisms for interaction effects observed both under 2-step and multi-step sequences were proposed. Results showed that atypical cycle ratio trends could result from loading sequences which involve combinations of strain amplitudes from different fatigue regimes (i.e. PDF or EDF). Mean strain effects on fatigue life were also studied. The objective of this study was to identify regimes of fatigue which are significantly influenced by mean strains. Results indicated that mean strains affected EDF but not PDF. 2-step tests, similar to those performed in earlier studies were conducted to investigate the effects of mean strain on variable amplitude loading. Again, atypical cycle ratio trends were observed for loading sequences involving combinations of PDF and EDF. It is understood that fatigue crack growth interaction behaviour and mean stress effects are two dominant mechanisms which can be used to explain cycle ratio trends observed. The significance and importance of proper PDF/EDF definition and specification are also stressed. The study of fracture mechanics is an important component of any fatigue research. Fatigue crack growth in 4140 high strength steel CT specimens, under conditions of plane stress and plane strain were studied. In this investigation, the effects of R and overload ratios were also studied for both plane stress and plane strain conditions. Results indicate that differences in the point of crack “initiation” under both plane stress and plane strain conditions decrease with increasing load range, while the extent of crack retardation as a result of overloading, is greater under plane stress than plane strain conditions. The extent of crack growth retardation increases with decreasing R ratios and increasing overload ratios. The final phase of this project involves the proposal of two practical models used to predict cumulative “damage” and fatigue crack propagation in metals. The cumulative “damage” model proposed takes the form of a power law and the exponent which governs “damage” accumulation can easily be calculated by knowing the failure life, Nf, for a given strain or load level. Predictions for the “damage” model performed better when compared to other popular cumulative “damage” models. The second model proposed predicts fatigue crack growth behaviour from known monotonic and smooth specimen fatigue data. There are several benefits of having a model that can predict fatigue crack growth from monotonic and smooth specimen fatigue data: a) traditionally, engineers had to rely on expensive and time-consuming crack propagation tests to evaluate and select materials for maximum fatigue resistance, and b) monotonic and smooth specimen fatigue data are readily available. The crack propagation model is proposed to alleviate the material selection process by providing engineers a means to rapidly eliminate and narrow down selections for possible material candidates.
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Chen, Jhewn-Kuang. "Effects of alloying elements upon austenite decomposition in high strength low alloy steels". Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-10102009-020227/.
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Külünk, Bahadir. "Aqueous modelling of aluminum wire injection procedures in steelmaking". Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66225.
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Daames, Sherwyn. "The metallurgical phase transformations in ROQ-tuf AD690 due to the MMA welding process". Thesis, Peninsula Technikon, 2002. http://hdl.handle.net/20.500.11838/1264.
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Thesis (MTech (Mechanical Engineering))--Peninsula Technikon, 2002Phase transformations in steel are of profound commercial importance due to the fact that they influence the physical and mechanical properties of the end product. During the casting process, which occurs at temperatures in excess of 1500°C, the microstructure of the steel is austenitic. During slow cooling the austenite will decompose into lower temperature microstructures such as ferrite, pearlite or hard, brittle cementite, the latter becoming increasingly present the higher the carbon content of the steel. Steel manufacturers, however, make use of additional forming processes such as rolling, quenching and reheat or tempering to impart specific mechanical or metallurgical properties to a particular steel. If the cooling rate is increased, as would be the case during a quenching process, the austenite will decompose forming a needle like microstructure called bainite in addition to the other microstructures. A further increase in the cooling rate will result in the diffusionless transformation of part of the austenite to form martensite, a hard brittle microstructure. If heat was now to be applied to the steel, as in a tempering process, some of the martensite formed during the quenching process will again transform into a softer microstructure such as pearlite or ferrite.
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Barritt, Andrew Stephen. "Detection of hydrogen embrittlement in steel and steel alloys using methods of neutron radiography". Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/32597.
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Yao, Lan Lance. "Atom probe microscopy of clustering and precipitation processes in microalloyed strip cast steels". Thesis, The University of Sydney, 2011. https://hdl.handle.net/2123/29282.
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The challenge of climate change is pushing the modern steel industry to focus on not only products with better properties and performance but also those produced by greener steelmaking processes. The CASTRIP® process is a recently-developed technology that can produce strip cast steels in a cheaper, more efficient and less energy-intensive way. Thin CASTRIP ® steel products are unprecedented in thickness at 0.8-1.5 mm and display very good mechanical properties. They are an excellent alternative to products made by hot and cold rolling methods that are relatively costly and less efficient.
Nb, a well-known effective element for grain refinement of steels, has been tentatively added into CASTRIP® plain carbon steels. Preliminary research outcomes showed finer microstructure and corresponding improved strength as the result of Nb additions. Moreover, Nb solutes are thought to be uniformly distributed within the grain. No obvious precipitates are found in the microstructure. Providing the well-known affinity between Nb and interstitials i.e. C and N, opportunities are hypothesised to further strengthening by utilising these Nb solutes in solid solution.
In this thesis, heat treatment is adopted to induce modification of the solid solution. Through ageing at 525° C, secondary phases are believed to be formed in the steels as the properties of tl1e aged sample are improved. Interestingly both yield strength and total elongation exhibit improvement despites the conventional dilemma in improving both of these antagonist properties. To explore the origins beyond this fascinating property changes, atom probe microscopy (APM) is adopted to provide materials information in three dimensions with near atomic resolution and high chemical sensitivity.
Several APM techniques have been developed essentially to support this project: The optimal experimental conditions for running microalloyed steel specimens, a filtering technique for atom probe microscopy data, a new method for the quantitative determination of crystal structure (plane spacings and angles between families of planes) via Hough transformation and the idea of time-chemical correlation in atom probe data were introduced and investigated.
Using these technical advances, unprecedented fine microscopic imaging and quantitative analyses of NbCN clustering processes in aged samples are characterized. It is concluded that the strengthening originates from both clustering and precipitation, leading to the win-win property change in both strength and ductility after ageing.
16
Zacharia, Nicole S. B. Massachusetts Institute of Technology. "Thermal imaging of quenched microstructural evolution in steel alloys". Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/118566.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2001.Cataloged from PDF version of thesis.
Includes bibliographical references (page 41).
A method was devised for quenching undercooled samples of Fe-12Cr-16Ni. The samples were levitated in a magnetic field as a way of containerless processing. They were dropped onto a nucleation trigger and then into a quenching bath. This process was successful in producing quenched samples , but the layer of In-Ga wetting their surface showed problematic in the analysis of the samples. Data shows that double recalescence was observed in a few cases. SEM proved inconclusive and was not sensitive enough to detect the small chemical variations expected in the dendrites. Also, across the entirety of the sample there was no significant partitioning of Cr or Ni.
by Nicole Zacharia.
S.B.
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Hiuhu, John. "Shear spinning of nickelbased super alloys and stainless steel". Thesis, Högskolan Väst, Avdelningen för maskinteknik och naturvetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-8685.
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Shear spinning of Haynes 282, Alloy 718, Alloy 600 and AISI 316L was done using several tool feeds and mandrel clearances. Multi passing of the materials was limited due to strain hardening and circumferential cracking except for AISI 316L. The effect of the tool feed and the mandrel clearance on the successful forming of the materials was established. The successfully spun samples were solution heat treated at varying temperatures and holding times to establish a range of grain sizes and hardness levels. An aging heat treatment process was performed for Haynes 282 and Alloy 718 to achieve precipitation strengthening. The micro hardness measurements were conducted for the materials prior to spinning and after spinning. The same was also done after the various heat treatment processes. Grain size mapping was conducted by the use of lineal intercept methods. Comparison of the results in terms of grain sizes and hardness values was done. The temperature ranges suitable for full recrystallization of the materials after the shear spinning were identified and the effect of the holding times on the grain growth established. Comparison with unspun samples showed that the heat treatment times required to achieve comparative hardness and grain sizes were distinctively different.
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Kish, Joseph J. "Active-passive corrosion of Fe-Cr-Ni alloys in hot concentrated sulphuric acid solutions /". *McMaster only, 1999.
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Mukherjee, Sunit. "Quantitative characterization of void nucleation and growth in HY-100 steels". Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/19574.
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Sulaiman, Samsiah. "Structure of properties of the heat affected zone of P91 creep resistant steel". Access electronically, 2007. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20080916.150054/index.html.
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Wang, Xiaolan. "The effects of rust on the gas carburization of AISI 8620 steel". Worcester, Mass. : Worcester Polytechnic Institute, 2008. http://www.wpi.edu/Pubs/ETD/Available/etd-073108-094449/.
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Thorpe, Adam. "The Sintering of maraging steel with phosphorous additions /". St. Lucia, Qld, 2003. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe17533.pdf.
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Martins, Meco Sonia Andreia. "Joining of steel to aluminium alloys for advanced structural applications". Thesis, Cranfield University, 2016. http://dspace.lib.cranfield.ac.uk/handle/1826/10288.
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When joining steel to aluminium there is a reaction between iron and aluminium which results in the formation of brittle intermetallic compounds (IMC). These compounds are usually the reason for the poor mechanical strength of the dissimilar metallic joints. The research on dissimilar metal joining is vast but is mainly focused on the automotive industry and therefore, the material in use is very thin, usually less than 1 mm. For materials with thicker sections the present solution is a transition joint made by explosion welding which permits joining of steel to aluminium and avoids the formation of IMCs. However, this solution brings additional costs and extra processing time to join the materials. The main goals of this project are to understand the mechanism of formation of the IMCs, control the formation of the IMCs, and understand their effects on the mechanical properties of the dissimilar Fe-Al joints during laser welding. Laser welding permits accurate and precise control of the welding thermal cycle and thereby the underpinning mechanism of IMC formation can be easily understood along with the factors which control the strength of the joints. The further goal of this project is to find an appropriate interlayer to restrict the Fe-Al reaction. The first stage of the work was focused on the formation and growth of the Fe-Al IMCs during laser welding. The understanding of how the processing conditions affect the IMC growth provides an opportunity to act and avoid its formation and thereby, to optimize the strength of the dissimilar metal joints. The results showed that even with a negligible amount of energy it was not possible to prevent the IMC formation which was composed of both Fe2Al5 and FeAl3 phases. The IMC growth increases exponentially with the applied specific point energy. However, for higher power densities the growth is more accentuated. The strength of the Fe-Al lap-joints was found to be not only dependent on the IMC layer thickness but also on the bonding area. In order to obtain sound joints it is necessary to achieve a balance between these two factors. The thermal model developed for the laser welding process in this joint configuration showed that for the same level of energy it is more efficient to use higher power densities than longer interaction iv times. Even though a thicker IMC layer is formed under this condition due to higher temperature there is also more melting of aluminium which creates a larger bonding area between the steel and the aluminium. The joint strength is thus improved ... [cont.].
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Al-Zamily, A. A. H. "Combined temperature and strain cycling effect on three steel alloys". Thesis, University of Bristol, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384447.
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Seth, Sampan. "Novel aluminium alloys for thermal spray applications to steel substrates". Thesis, Sheffield Hallam University, 2015. http://shura.shu.ac.uk/20345/.
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?Extensive research on alloying aluminium (Al) with zinc (Zn), indium (In) and titanium (Ti) to improve corrosion and wear resistance has been conducted since 1950's to meet the increased demand of Al in construction, automotive, aerospace and food industries in the form of coatings deposited using thermal spraying, hot dipping and cladding. This research has investigated the performance of arc sprayed Al-5wt%Zn-(0.02-0.05wt%)ln and Al-3wt%Ti-0.15wt%C coatings to protect steel structures from corrosion and wear. The accelerated and electrochemical tests conducted on Al-5wt% Zn-(0.02-0.05wt%) In showed that its superior corrosion performance was attributed to the synergetic interaction of Zn and In. Cyclic formation and rupturing of passive Al oxide layer was found to be the underlying mechanism of activation produced by combination of both Zn and In. The presence of In in the corrosion product or on the surface of the coating In was not detected, hence validation of surface enrichment theory was improbable. The micro-scale abrasive wear test showed that the wear coefficient of an arc sprayed Al-3wt%Ti-0.15wt% C coating was found to be very close to that of an arc sprayed 13wt%Cr steel coating with a much higher hardness. This was attributed to the formation of Al[3]Ti and (Ti,Al)C particles due to rapid cooling that takes place in arc spraying . This resulted in precipitation strengthening, explAlning the increase in the hardness of the sprayed Al-3wt%Ti-0.15wt%C coating compared to its feedstock alloy. To establish a mechanism by which the identified phases in the microstructure of arc sprayed Al-3wt%Ti-0.15wt%C alloy coating showed improved hardness and wear resistance than the bulk alloy, growth of identified phases in the coating was promoted by two different heat treatment cycles. The coated samples were held at three chosen temperatures of 150°C, 350°C and 550°C separately for 1 hour and 3 hours, followed by two different cooling regimens; the first involved rapid quenching of samples and the other was room temperature exposure for 5 hours. After both heat treatment cycles; Precipitations of Ti rich high contrast and near spherical brittle phases were observed in the microstructure of Al-3wt%Ti coatings. A reduction in the spread of micro-hardness value with increase in exposure temperature from 150°C to 550°C was also observed. An overall increase in the wear coefficient value of rapidly quenched coatings in comparison to as-sprayed Al-3wt%Ti-0.15wt%C coating was seen. A similar increase in the wear coefficient value was also observed after room temperature cooled coatings. However, an exceptional 15 % reduction in wear coefficient value was seen in the room temperature cooled coating after 3 hours of exposure at 550°C. The role of precipitated phases and possible mechanism of their effect on micro-hardness and wear resistance of Al-3wt%Ti-0.15wt%C alloy coating has also been discussed.
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Kalcioglu, Ali Ferdi 1960. "Distribution of antimony between carbon-saturated iron and blast furnace slags". Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/277129.
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Understanding the effects of the process parameters on the distribution behaviour of antimony between metal and slag in the iron blast furnace is critical to develop a universal method of controlling temper embrittlement in commercially pure low alloy steels.
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Yin, Maggie Huaying Materials Science & Engineering Faculty of Science UNSW. "Metal dusting of iron and low alloy steel". Awarded by:University of New South Wales. School of Materials Science and Engineering, 2006. http://handle.unsw.edu.au/1959.4/25188.
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Metal dusting is a kind of catastrophic corrosion phenomenon that can be observed in several of petrochemical processes. It occurs on iron-, nickel- and cobalt-base metals in carbonaceous atmospheres at high temperature when gaseous carbon activity is higher than one. The process is particularly rapid for ferritic alloys The aim of this project was to compare the dusting kinetics of pure iron and a 2.25Cr-1Mo alloy steel under CO-H2-H2O atmosphere at 650??C. Polished (3??m) samples of iron and the steel were exposed to flowing CO-H2-H2O gas atmospheres at 650??C, when the gases were supersaturated with respect to graphite. The partial pressure of CO was varied between 0.25 and 0.9 atm, and the carbon activity was varied from 2.35 to 16, in order to obtain a series of experimental conditions. In most experiments, pO2 was less than 7.37E-24 atm, and no iron oxide could form. However, Cr2O3 would always have been stable. When exposed to these gases, both iron and steel developed a surface scale of Fe3C which was buried beneath a deposit of carbon, containing iron-rich nanoparticles (the dust). Examination by Scanning Electron Microscopy allowed the observation of fine and coarse carbon nanotubes, and also spiral filaments. However, the morphology of the graphitic carbon was not sensitive to pCO and aC. Moreover, the carbon deposit was gas permeable, allowing continuing gas access to the underlying metal. At a fixed=4.5, the carburizing rate clearly increased with CO content from 0.25 to 0.68 atm. However, increasing the CO content to higher value led to decreased rates, indicating that carburizing rate reaches a maximum value at pCO=0.68 atm. When pCO was fixed at 0.25 atm and 0.68 atm, and carbon activity was varied. The induction period was extended by the formation of protective oxide layers at low values of carbon activity (aC= 2.35 and 2.55) where pO2 exceed the iron oxide formation value. For other reaction conditions, the carbon uptake rate for iron and steel did not increase with aC. The present work showed that the carbon deposition rates were not proportional to pCO or pCOpH2. Instead, the rate was affected by the partial pressure of all three reaction gases, and the carbon uptake rate for both materials could be expressed at r=k1pCOpH2+k2pCO2+k3pH22 and the rate constant k3 has a negative value, corresponding to coke gasification. From XRD analyses, it was found that cementite was the only iron-containing phase in the dusting product. The cementite particles acted as catalysts for carbon deposition from the gas. The same deposition process at the surface of the cementite layer led to its disintegration, thereby producing the particles. This disintegration process was faster on the steel than on pure iron. Consequently, the rates of both metal wastage and coke accumulation were faster for the steel. It is concluded that chromium and molybdenum do not stabilize the carbide but accelerate its disintegration process. It is suggested that Cr2O3 fine particles in the cementite layers provide more nucleation sites in the cementite layer on steel, explaining its more rapid dusting kinetics. However, appropriate methods of proving this assumption, such as TEM and FIB, are required.
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Anderson, Danny. "Effect of the joint addition of aluminum and molybdenum on the precipitation and recrystallization in HSLA steels". Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66207.
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Xie, Kelvin Yu Xuan. "The effect of niobium-rich clusters on the mechanical properties of ultra-thin strip cast steels produced by the CASTRIP® process". Thesis, The University of Sydney, 2012. http://hdl.handle.net/2123/17140.
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Armstrong, Derek C. "Influence of segregated impurities on the corrosion and oxidation of ferrous alloys". Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239600.
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Wolff, Ira M. "Ductility in high chromium super-ferritic alloys". Doctoral thesis, University of Cape Town, 1989. http://hdl.handle.net/11427/22200.
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Includes reprints of author's related articles.Bibliography: pages 187-201.
The competition between microfracture and plastic flow has been studied in relation to the thermomechanical processing parameters and minor element chemistry of wrought super-ferritic alloys based on a composition of Fe-40wt% Cr. These alloys have been developed for corrosion-resistant applications, specifically by micro-alloying with platinum group metals to induce cathodic modification, but their use has been hampered by inadequate toughness at ambient temperatures. Brittle cleavage of the alloys is a consequence of the high resistance to plastic flow required to accommodate local stresses, such as those found ahead of a loaded crack. Once initiated, a crack propagates in a brittle manner with minimal ductility. The impact toughness therefore relies on the ability of the alloys to withstand crack initiation. The frequency of the crack initiation events is related to the distribution of secondary phases within the matrix and at the grain boundaries. A direct means of improving the toughness and the ductility is accordingly via annealing cycles and minor alloying additions to control the precipitation of second phases. The ductility is enhanced by raising the mobile dislocation density, and this may be achieved by pre-straining recrystallised material, or increasing the number of dislocation sources in the otherwise source-poor material. The generation of mobile dislocations by prismatic punching at second phase particles in response to local or tessellated stresses was found to increase the ductility and the impact toughness of the alloy. The addition of nickel also increases the brittle fracture resistance by promoting stress accommodation at the crack tip, a result which can, in principle, be explained on the basis of enhanced dislocation dynamics. The tendency of the alloys to form a stable recovered substructure was identified as a critical parameter for both the mechanical and corrosion properties. The low-angle dislocation sub-arrays contribute to overall strain-hardening, but destabilise the passivity of the alloys in acid media. In practice, rationalisation of the microstructural parameters has enabled the practicable fabrication of tough, corrosion-resistant alloys, suitable for commercial development.
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Coffey, Melvin W. "The effect of antimony on segregation during dendritic solidification in a cast modified 4720 alloy /". Full text open access at:, 1985. http://content.ohsu.edu/u?/etd,93.
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Watson, Maxine. "Phase stability, constitution and precipitation effects in Fe-Ni-Cr alloys". Thesis, Sheffield Hallam University, 1990. http://shura.shu.ac.uk/20503/.
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A study of the constitution, transformation and precipitation effects in ternary Fe-Cr-Ni alloys and quaternary Fe-Cr-Ni-X alloys containing Mo, Nb, Ti, and Si was carried out. A systematic approach was adopted so that the microstructural effects observed as a result of ageing the selected iron base ternary alloys could be directly compared to the quaternary alloys. A series of ageing curves were plotted for the six ternary alloys over the temperature range 400°-900°C and for the ten quaternary alloys in the temperature range 650°-850°C. Optical and electron metallography were used to study the transformation and precipitation of intermetallic phases and carbides in the aged microstructures. The transformation of delta ferrite to sigma phase in a duplex (gamma+delta) ternary alloy was studied. The transformation was preceded by the precipitation of a cellular structure which formed on the delta/gamma grain boundaries and consisted of M23C6 and new austenite. A complex transformation product, which resembled a region of imiscibility, then formed at the delta/(gamma + M23C6) interface, this product consumed the delta ferrite grain, eventually transforming to sigma phase and new austenite. The alpha' phase, more commonly referred to as 475°C embrittlement, was also observed precipitating in the delta ferrite grains in two of the iron based ternary alloys in the temperature region 400°-500°C. Overageing of the alpha' precipitates after 1000 hours at 500°G was accompanied by the precipitation of a rod like austenite. The elements 2%Mo, 1%Nb, 1/4%Ti and 1% and 2%Si were added totwo Fe-Ni-Cr base alloys. One alloy was an austenitic (20Cr,23Ni) and the other was a transformable alloy (18Cr, 7Ni). The quaternary element additions had no effect on the constitution of the austenitic ternary alloy. However the addition of Mo to the 18Cr, 7Ni ternary alloy caused the transformation of delta ferrite to sigma phase over ageing temperature range 650°-850°C. The addition of Si moved the constitution of the ternary alloy further into the gamma+delta phase field, a small amount of sigma phase was observed in the 2%Si quaternary alloy on ageing at 650°C for 1000 hours. Irradiation damage studies were performed using High Voltage Electron Microscope and Variable Energy Cyclotron. The effect ofthe quaternary alloying additions Mo, Si, and Nb on the voidswelling behaviour of a 20Cr, 23Ni alloy were studied using 46MeV Ni6 ions in the Variable Energy Cyclotron, irradiating to a total dose of 10dpa at 550°C. All additions reduced void swelling, the largest reduction was observed in the Si containing allov. The Insert A Thermal ageing showed the presence of M23C6 the amount of which increased with increasing ageing temperature. No delta ferrite was observed in these alloys.
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Hu, Rong. "Irradiation effects on Fe-Cr alloys". Thesis, University of Oxford, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.560928.
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Ferritic chromium steels are important structural materials for future nuclear fission and fusion reactors due to their advantages over traditional austenitic steels, including low swelling rates, better thermal fatigue resistance, and lower thermal expansion coefficients. Radiation-induced segregation or depletion (RIS/RID) of solute atoms at grain boundaries is considered to be a potentially significant phenomenon for structural materials because of its potentially detrimental role in affecting microstructure and furthermore mechanical properties. However, the behaviour of Cr at grain boundaries in ferritic steels is not well understood. Both segregation and depletion of Cr at grain boundary under irradiation have been previously observed and no clear dependency on irradiation condition or alloy type has been presented. Furthermore, ferritic alloys are known to undergo hardening and embrittlement after thermal aging in the temperature range of 300-550DC and this phenomenon is related with a and a' phase separation occurring in the solid solution. However the low temperature a-a' miscibility gap in the currently used phase diagram is extrapolated from high temperature results and conflicts with many experimental observations. To understand the Cr behaviour at gram boundaries in ferritic steels under irradiation, a systematic approach combining SEM/EBSD, FIB specimen preparation and APT analysis has been developed and successfully applied to a Fe- 15.2at%Cr to investigate the effect of pre-irradiation chemistry, grain boundary misorientation, impurities, irradiation damage, irradiation depth, and other possible factors to get a better understanding of RIS/RID phenomena. Both low sigma boundaries and randomly selected high angle boundaries have been investigated in detail. Systematic differences between the behaviour of different classes of boundaries had been observed, and the operating mechanisms are also discussed in this thesis. The maximum separation method has been applied on APT data to study the C- enriched clusters and Cr-enriched clusters, which were not directly visible on the atom maps. The composition of the Cr-enriched clusters was consistent with a' phase and the irradiation was found to accelerate the nucleation rather than the growth of these clusters. Such results provided important information in re- determining the a-a' phase boundary.
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Kim, Yeong Ho. "Chromium-free consumable for welding stainless steel corrosion perspective /". Columbus, Ohio : Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1133285376.
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Bowen, J. R. "The formation of ultra-fine grained model aluminium and steel alloys". Thesis, University of Manchester, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.508036.
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Bowden, David. "Assessment of cobalt-free hardfacing stainless steel alloys for nuclear applications". Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/assessment-of-cobaltfree-hardfacing-stainless-steel-alloys-for-nuclear-applications(3da6a424-94af-4d11-82fa-92dc3b7ddded).html.
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Hardfacing alloys are utilised in pump and valve components in pressurised water reactors (PWR's). They are designed to withstand wear and galling effects, which occur as a result of surface-to-surface contact, where surface roughness increases by localised plastic deformation, resulting in fracture and material transfer. Typically, alloys that exhibit suitable hardness and galling resistance are known as the Stellites; a Co-base alloy family. Whilst these Co alloys perform well in a hardfacing capacity, they suffer from neutron activation and subsequently decay, forming 60Co isotopes, which emit hazardous γ-rays, contributing to plant worker exposure. The present study was developed to characterise and assess the metallurgical properties of two candidate Co-free replacement alloys; stainless Fe-based alloys Tristelle 5183 and a derivative alloy, developed and patented by Rolls-Royce, known as RR2450. The alloys are produced as gas-atomised powders before undergoing hot isostatic pressing (HIP) into usable parts in-service. As part of this work, we have identified a novel, high-strength Fe-Cr-Ni silicide phase, which precipitates extensively within the RR2450 alloy after HIP consolidation, resulting in the formation of a triplex (austenite/delta- ferrite/silicide) matrix. The use of automated diffraction tomography (ADT) has allowed the crystallography of this phase to be determined as a trigonal R3 space group setting. A carbon atom, identified at a trigonal bipyramidal site along [111] within the silicide phase unit cell, indicates a carbon solubility of up to 1.2 wt% within this phase. HIP cycles were studied in situ using synchrotron X-ray diffraction (XRD), which revealed that the silicide phase decomposes within the metastable gas-atomised RR2450 powder by a eutectoid γ → delta + M7C3 transformation. The starting fraction of metastable delta-ferrite within the RR2450 gas-atomised powder is shown to directly influence the rate of transformation from γ to delta-ferrite during the HIP cycle. The wear resistance of the triplex RR2450 alloy at 300 °C is shown to be superior when compared to the austenitic Tristelle 5183. This is attributed to the high strength silicide phase, which is shown to offer a hardness up to 2 to 2.5 times greater than the austenite and delta-ferrite phases. By producing an elastic angular distortion of the unit cell, the silicide phase is able to withstand loading up to 1 GPa without yielding. The Tristelle 5183 alloy, which produces a lower fraction of silicide phase compared to RR2450, is reliant on the formation of stacking faults and a strain induced martensitic transformation to provide a high wear resistance. These transformations are shown to reduce substantially during wear testing at 190 °C, leading to a loss of high temperature wear resistance in the Tristelle 5183 alloy. Future work into developing silicide based Fe hardfacings is suggested, the microstructures of which can be tailored by controlling Si and Ni additions.
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Al, Tooq Zainab. "Simulating radiation damage in austenitic stainless steel and Ni-based alloys". Thesis, Loughborough University, 2013. https://dspace.lboro.ac.uk/2134/12599.
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The evolution of materials at an atomistic level may have vital consequences for the properties of materials. Therefore, modelling long time scale behaviour of defects in a material is very important, particularly for those used in nuclear power plants. The materials used in nuclear power plants should have good mechanical properties to overcome the corrosive environment and high temperature. Examples of these materials are the austenitic stainless steel and the Ni-based alloys due to their high temperature properties. Molecular Dynamics (MD) and on the fly Kinetic Monte Carlo (otf-KMC) techniques have been used to model the radiation damage in austenitic stainless steel and the Ni-based alloys. This thesis represents the main findings obtained. Three potentials were implemented and used to study radiation damage in austenitic stainless steel. Structural properties such as the elastic constants for the point defects in the pure metals were first calculated. This was followed by calculating the formation energies and migration energies of vacancy and self interstitial defects in the pure metals. Different calculations were performed using each potential on the ternary alloy (Fe with 10 at.% Ni and 20 at.% Cr) and the binary alloy (Ni with 20 at.% Cr) . For example, the segregation in these alloys was investigated using Monte Carlo simulations and results obtained for both alloys at high temperature MD. Furthermore, the vacancy formation energies were calculated for both alloys using all the potentials. Radiation damage at Grain Boundaries (GBs) in fcc Ni and a Ni-Cr binary alloy has been studied using MD and otf-KMC techniques. From the results obtained, the mobility of interstitials were found to be higher than that of vacancies and tend to move quickly to the GB. Vacancies are found to migrate to the GB if they are near otherwise they tend to form clusters in the bulk. During the simulations, interesting mechanisms were observed for the point defects migration and recombinations. Large roughening at the GB was observed, especially in the alloy system and overall the total number of defects accumulated on the GB after multiple collision cascades were relatively small. The radiation in fcc Ni resulting from low energy collision cascades was also modelled using MD and otf-KMC techniques. This part of work aimed replicating the observations seen in experiment and trying to understand them. Recombinations between vacancies and interstitials were found to happen from large distances with low barriers. Most defects produced from low energy collision cascades were found to recombine or interstitials were found to form clusters. Modelling the evolution of the vacancies shows the possibility of producing Stacking Fault Tetrahedra (SFT) which were found to dissociate at 200°C.
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Daggula, Manikantha Reddy. "REPLACEMENT OF STEEL PARTS WITH EXTRUDED ALUMINUM ALLOYS IN AN AUTOMOBILE". OpenSIUC, 2016. https://opensiuc.lib.siu.edu/theses/2053.
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Over the past years, vehicle emissions have shown a negative impact on environment and human health. A new strategy has been used by automakers to reduce a vehicle’s weight which significantly reduce fuel consumption and C02 emissions. A very light car consumes very less fuel as it needs to overcome less inertia, decreasing the required power to movie the vehicle. Reducing weight is the easiest way to increase fuel economy and making it by just 10% can increase its efficiency 6 to 8 percent. For a normal scale 80% of vehicles weight is shared among chassis, power train and other exterior components. Almost 60% of the vehicles weight is comprised of steel and the remaining is with cast and extruded aluminum and magnesium alloys. Our main aim is to look for the parts like Fuel tank holder, Fuel filler neck, Turbo inlet assembly, and Brake lines, Dash board frame which are made from steel and replace them with extruded aluminum alloys, to analyze a conventional rear wheel aluminum drive shaft and replace it with a new design and with a new aluminum alloy. The current project involves dismantling an automobile and looking for feasible steel parts and making samples, analyzing the hardness of the samples. These parts are optimally analyzed using Ansys Finite element analysis tool, these parts are subjected to the constraints such as three-point bending, tensile testing, hydrostatic pressure and also torsional stress action on the drive shaft, the deformation and stress are observed in these parts. The results show the current steel parts can be replaced with 3000 series aluminum alloy and the drive shaft can be replaced with new design with 6061-T6 Al-alloy which decreases 25% of the shaft weight.
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Dogo, Harun. "Point defect properties in iron chromium alloys". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2006. http://library.nps.navy.mil/uhtbin/hyperion/06Sep%5FDogo.pdf.
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Thesis (M.S. in Applied Physics)--Naval Postgraduate School, September 2006.Thesis Advisor(s): Craig Smith, Xavier Maruyama. "September 2006." Includes bibliographical references (p. 57-59). Also available in print.
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Watkins, Mark Edward. "Calcium modification of surface oxides formed on levitated iron and steel alloy droplets and related surface tension phenomena /". The Ohio State University, 1987. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487330761217245.
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Sneddon, A. D. "Macrofouling and corrosion of steels and copper-nickel alloys in seawater". Thesis, Robert Gordon University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378071.
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Hays, Richard A. "Surface residual stress effects on stress corrosion cracking/hydrogen embrittlement behavior of AISI 4340 steel". Thesis, Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/80148.
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A series of experiments was performed in an attempt to measure the effects of surface residual stresses on the stress corrosion cracking/hydrogen embrittlement (SCC/HE) behavior of AISI 4340 steel. Stress corrosion tests were performed under load control on cylindrical and notched tensile specimens in acidified 3.5% NaCl solution. The electrochemical potential of the specimens was maintained at -0.7 V versus a saturated calomel reference electrode. Time to failure for specimens tested at various applied and residual stress levels was measured. Stress relieved specimens as well as specimens containing mechanically induced residual stresses were tested. Residual stresses were estimated using Neuber's rule and were measured using an x-ray diffraction technique. In all cases, the sum of the applied and residual stresses was greater than zero.
Test results showed the initiation of SCC/HE cracks to be insensitive to the effects of surface residual stresses under the conditions evaluated. This is probably a result of the total time to failure criterion used to evaluate the SCC/HE tests. The extremely aggressive environment used in these experiments apparently led to rapid crack initiation, even in specimens containing compressive residual stresses. Another possible explanation of the insensitivity of this series of tests is crack initiation in the interior of the specimens below the depth of the mechanically induced residual stresses.Master of Science
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Komarasamy, Mageshwari. "Deformation Micro-mechanisms of Simple and Complex Concentrated FCC Alloys". Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc822829/.
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The principal objective of this work was to elucidate the effect of microstructural features on the intrinsic dislocation mechanisms in two FCC alloys. First alloy Al0.1CoCrFeNi was from a new class of material known as complex concentrated alloys, particularly high entropy alloys (HEA). The second was a conventional Al-Mg-Sc alloy in ultrafine-grained (UFG) condition. In the case of HEA, the lattice possess significant lattice strain due to the atomic size variation and cohesive energy differences. Moreover, both the lattice friction stress and the Peierls barrier height are significantly larger than the conventional FCC metals and alloys. The experimental evidences, so far, provide a distinctive identity to the nature and motion of dislocations in FCC HEA as compared to the conventional FCC metals and alloys. Hence, the thermally activated dislocation mechanisms and kinetics in HEA has been studied in detail. To achieve the aim of examining the dislocation kinetics, transient tests, both strain rate jump tests and stress relaxation tests, were conducted. Anomalous behavior in dislocation kinetics was observed. Surprisingly, a large rate sensitivity of the flow stress and low activation volume of dislocations were observed, which are unparalleled as compared to conventional CG FCC metals and alloys. The observed trend has been explained in terms of the lattice distortion and dislocation energy framework. As opposed to the constant dislocation line energy and Peierls potential energy (amplitude, ΔE) in conventional metals and alloys, both line energy and Peierls potential undergo continuous variation in the case of HEA. These energy fluctuations have greatly affected the dislocation mobility and can be distinctly noted from the activation volume of dislocations. The proposed hypothesis was tested by varying the grain size and also the test temperature. Activation volume of dislocations was a strong function of temperature and increased with temperature. And the reduction in grain size did not affect the dislocation mechanisms and kinetics. This further bolstered the hypothesis. The second part deals with deformation characteristics of Al-Mg-Sc alloy. The microstructure obtained from the severe plastic deformation (SPD) techniques differ in dislocation density, grain/cell size, and in the grain boundary character distribution. Therefore, it is vital to understand the deformation behavior of the UFG materials produced by various SPD techniques, as the microstructural features basically control the deformation mechanisms. In this study, a detailed analysis was made to understand the deformation mechanisms operative in various regimes of a stress-strain in UFG Al-Mg-Sc alloy produced via friction stir processing. The stress-strain curves exhibited serrations from the onset of yielding to the point of sample failure. The serration amplitude and frequency was higher in UFG material as compared to CG material. Furthermore, the microstructural features that result in the serrated flow were investigated along with the avalanche characteristics. The presence of both ultrafine grains and Al3Sc precipitates were the necessary conditions to reach the critical stress required to push the grain boundary into a critical state to set off an avalanche. The microstructural conditions that did not satisfy both the requirements did not exhibit deep serrations.
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Adolfi, Sofia. "Slag inclusion formation during solidification of steel alloys and in cast iron". Licentiate thesis, Stockholm : Materialvetenskap, Kungliga Tekniska högskolan, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4371.
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Elmer, John Walter. "The influence of cooling rate on the microstructure of stainless steel alloys". Thesis, Massachusetts Institute of Technology, 1988. http://hdl.handle.net/1721.1/14615.
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Kertz, Joan Elizabeth 1975. "The kinetics of growth competition during rapid solidification of ternary steel alloys". Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/8456.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2001.Includes bibliographical references (leaves 99-102).
The rapid solidification growth behavior of ternary stainless steel alloys was examined using electromagnetic levitation and high-speed digital imaging, and the growth behavior of the stable fee austenite (gamma) phase into the pre-existing metastable bee ferrite [delta] solid/liquid dendrite array was successfully modeled. Alloys with equal thermal driving force for growth during secondary recalescence but different solute concentrations were selected and compared. The growth velocity of stable -y into the metastable [delta]/l semi-solid (Vss ) was confirmed to be independent of undercooling and was determined to be a function of solute concentration. Because the build-up of solute ahead of the dendrite acts to slown down the growing tip, growth velocity decreases as solute concentation increases. It has been shown previously that at a given undercooling, the fee phase grows faster into the bee solid/liquid array when compared to growth into liquid alone. A growth model involving heat extraction was developed that successfully characterizes this behavior. In the model, heat is extracted from the austenite dendrite tip to the pre-exisitng ferrite solid, which acts as a heat sink. The latent heat of fusion rejected at the tip to the liquid is reduced. The solid fee is able to grow into the bee semi-solid at a faster rate because the barrier to growth is curtailed. The model predicts that the amount of heat extracted to the solid, H s, is a linear function that decreases to zero as thermal driving force increases. After heat extraction ceases. the growth velocity of austenite into semi-solid is expected to behave analogous to the growth rate into liquid. It was determined that the difference between the growth velocity into semi-solid and growth into liquid, [Delta]V, actually depends on the product of Hs and Vss , or the rate of heat extraction, J. As thermal driving force increases, both [Delta]V and J increase to the a local maximum before decreasing to zero at the same rate. The model values of Hs can be used in conjunction with existing dendrite growth theory to predict Vss. The resulting velocity for alloys with equal solute concentration is a linear function of thermal driving force, with the slope depending on the empirically determined kinetic coefficient. Experimental values and model predictions for both Hs and Vss agree well.
by Joan Elizabeth Kertz.
S.M.
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McCarty, David Hughes Mary Leigh. "Durability of nitinol for structural applications". Auburn, Ala., 2006. http://repo.lib.auburn.edu/2006%20Summer/Theses/MCCARTY_DAVID_39.pdf.
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Howell, Ryan Andrew. "Microstructural influence on dynamic properties of age hardenable FeMnAl alloys". Diss., Rolla, Mo. : Missouri University of Science and Technology, 2009. http://scholarsmine.mst.edu/thesis/pdf/Howell_09007dcc80689c38.pdf.
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Thesis (Ph. D.)--Missouri University of Science and Technology, 2009.Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed August 25, 2009) Includes bibliographical references.
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Cunningham, David R. "Determination of residual stresses in HSLA-100 steel weldments as a function of welding parameters using x-ray diffraction". Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-11102009-020348/.
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