Log in

Relevant bibliographies by topics / Nickel alloys / Dissertations / Theses

To see the other types of publications on this topic, follow the link: Nickel alloys.

Dissertations / Theses on the topic 'Nickel alloys'

Author: Grafiati

Published: 4 June 2021

Last updated: 29 July 2024

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 dissertations / theses for your research on the topic 'Nickel alloys.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.

1

Wang, Shangyu. "Electrochemical properties of nanocrystalline nickel and nickel-molybdenum alloys." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq22500.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Abraham, Matthias. "Electrodeposition and characterisation of nanocrystalline nickel and nickel alloys." Thesis, University of Oxford, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269947.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Heritage, Neil. "Inverse photoemission from nickel and nickel-iron alloys and photoemission from magnesium-transition metal alloys." Thesis, University of Liverpool, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333675.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

Piers, Newbery A. "Electric arc spray forming of nickel alloys and nickel aluminides." Thesis, University of Oxford, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359486.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Lain, M. J. "Electrocatalytic hydrogenation on in-situ electrodeposited nickel and nickel alloys." Thesis, University of Southampton, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356694.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Pattinson, John. "Localised corrosion in nickel-based alloys." Thesis, University of Cambridge, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315133.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Rule, James R. "Friction Stir Processing Nickel-Base Alloys." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1306421751.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Altunoglu, Abdulkadir. "Hydrogen permeation through nickel and nickel alloys : surface reactions and trapping." Thesis, n.p, 1994. http://oro.open.ac.uk/19842/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Leith, Steven D. "Electrodeposition of NiFe 3-D microstructures /." Thesis, Connect to this title online; UW restricted, 1998. http://hdl.handle.net/1773/9855.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Kaya, Irfan. "SHAPE MEMORY BEHAVIOR OF SINGLE AND POLYCRYSTALLINE NICKEL RICH NICKEL TITANIUM ALLOYS." UKnowledge, 2014. http://uknowledge.uky.edu/me_etds/37.

Full text

Abstract:

NiTi is the most commonly used shape memory alloy (SMA) and has been widely used for bio-medical, electrical and mechanical applications. Nickel rich NiTi shape memory alloys are coming into prominence due to their distinct superelasticity and shape memory properties as compared to near equi-atomic NiTi shape memory alloys. Besides, their lower density and higher work output than steels makes these alloys an excellent candidate for aerospace and automotive industry. Shape memory properties and phase transformation behavior of high Ni-rich Ni54Ti46 (at.%) polycrystals and Ni-rich Ni51Ti49 (at.%) single-crystals are determined. Their properties are sensitive to heat treatments that affect the phase transformation behavior of these alloys. Phase transformation properties and microstructure were investigated in aged Ni54Ti46 alloys with differential scanning calorimetry (DSC) and transmission electron microscopy (TEM) to reveal the precipitation characteristics and R-phase formation. It was found that Ni54Ti46 has the ability to exhibit perfect superelasticity under high stress levels (~2 GPa) with 4% total strain after 550°C-3h aging. Stress independent R-phase transformation was found to be responsible for the change in shape memory behavior with stress. The shape memory responses of [001], [011] and [111] oriented Ni51Ti49 single-crystals alloy were reported under compression to reveal the orientation dependence of their shape memory behavior. It has been found that transformation strain, temperatures and hysteresis, Classius-Clapeyron slopes, critical stress for plastic deformation are highly orientation dependent. The effects of precipitation formation and compressive loading at selected temperatures on the two-way shape memory effect (TWSME) properties of a [111]-oriented Ni51Ti49 shape memory alloy were revealed. Additionally, aligned Ni4Ti3 precipitates were formed in a single crystal of Ni51Ti49 alloy by aging under applied compression stress along the [111] direction. Formation of a single family of Ni4Ti3 precipitates were exhibited significant TWSME without any training or deformation. When the homogenized and aged specimens were loaded in martensite, positive TWSME was observed. After loading at high temperature in austenite, the homogenized specimen did not show TWSME while the aged specimen revealed negative TWSME.

APA, Harvard, Vancouver, ISO, and other styles

11

Raza, Syed Shehzad. "Thermal Analysisi of Nickel Based Super Alloys." Thesis, KTH, Materialvetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-127258.

Full text

APA, Harvard, Vancouver, ISO, and other styles

12

Henderson, Alistair. "Abrasive flow machining of nickel based alloys." Thesis, University of Nottingham, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.422738.

Full text

APA, Harvard, Vancouver, ISO, and other styles

13

Fretwell, Grant Michael. "On the biocompatibility of nickel titanium alloys." Thesis, University of Liverpool, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366485.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Baldwin, K. R. "The corrosion of electrodeposited zinc-nickel alloys." Thesis, Cranfield University, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334720.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

Rodelas, Jeffrey M. "Friction Stir Processing of Nickel-base Alloys." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1341512683.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

El-Sharif, M. R. "Continuous codeposition of chromium-nickel and chromium-nickel-iron alloys from aqueous amide electrolytes." Thesis, University of the West of Scotland, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376533.

Full text

Abstract:

There are numerous reports of attempts to deposit thick coatings of chromium-nickel and chromium-nickel-iron and although high quality deposits have been obtained these have been limited to very thin coatings only. The purpose of the present work was to identify and understand the controlling factors preventing continuous deposition and the build-up of thick coatings, and to develop a suitable process for such thick coatings. An amide electrolyte system was chosen asworking model for its relative simplicity and the high quality chromium-nickel deposits obtained from this system. This bath was investigated initially using conventional operating techniques (Constant Current) to establish its general characteristics. High quality deposits were obtained for thin coatings only. The need for a major change of operating philosophy was identified as essential. A number of published hypotheses explaining the failure of continuous deposition were experimentally tested and shown not to apply. Electrolytically generated chromium (II) has been identified to be an important controlling factor on the quality and composition of chromium-nickel alloys codeposited from amide electrolytes. The control of the low transient chromium (II) level, necessary for the maintenance of high quality codeposition with constant composition, can be achieved as follows. A controlled potential is required, in combination with circulation and agitation of the electrolyte and the generation of the chlorine gas as the preferred anodic product. The combination of the three techniques is necessary for the control of chromium (II) and if any of the three techniques are not employed sustained deposition fails. Chromium (II) has further been identified to catalyse an electrochemical ageing of the bath. Reproducible high quality true metallic deposits of constant composition of chromium-nickel and chromium-nickel-iron can be obtained to a thickness of several hundred microns. These have shown to display a laminar structure on etching and possible causes have been considered. Mossbauer spectroscopy and x-ray diffraction have shown that chromium-nickel-iron deposits contain a significant quantity of micro-crystalline austenite phase ~, fcc) with a dominant ferrite (e<, bcc) phase.

APA, Harvard, Vancouver, ISO, and other styles

17

Lei, Kuan-Shaur. "Breakdown of the passive film on monocrystalline and polycrystalline nickel by chloride ions /." The Ohio State University, 1985. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487263399025293.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Coulter, Robert A. "Alloying effects on high temperature deformation behavior of nickel aluminide intermetallics." Morgantown, W. Va. : [West Virginia University Libraries], 2000. http://etd.wvu.edu/templates/showETD.cfm?recnum=1382.

Full text

Abstract:

Thesis (M.S.)--West Virginia University, 2000.
Title from document title page. Document formatted into pages; contains xi, 94 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 88-89).

APA, Harvard, Vancouver, ISO, and other styles

19

Muteba, Itone. "Research on nickel alloy sensitivity." Title page, Contents and Abstract only, 1999. http://web4.library.adelaide.edu.au/theses/09DM/09dmm992.pdf.

Full text

Abstract:

"April 1999." Includes bibliographical references (leaves 46-51). Aims to collect information about the numbers of dental workers who are sensitive or allergic to nickel and to help identify signs which might predict those people who are most likely to be sensitive to nickel. Uses a standard patch test to identify sensitive subjects.

APA, Harvard, Vancouver, ISO, and other styles

20

Barbero, Bernal Laura Isabel. "Cyclic Behavior of Superelastic Nickel-Titanium and Nickel-Titanium-Chromium Shape Memory Alloys." Thesis, Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4937.

Full text

Abstract:

Shape memory alloys (SMAs) are a class of alloys that display the unique ability to undergo nonlinear deformations and return to their original shape when heat is applied or the stress causing the deformation is removed. This unique shape memory characteristic is a result of a martensitic phase-change, which can be temperature induced (shape memory effect) or stress induced (superelastic effect). In this study, the cyclical behavior of NiTi, a binary shape memory alloy, is compared to the cyclical behavior of NiTiCr, a ternary SMA. The purpose of this study is to compare the behavior of a 0.085-in. diameter NiTiCr wire with the behavior of the same size NiTi wire to determine whether ternary SMAs are more viable ways to take advantage of the unique properties of SMAs for seismic applications. The experimental results showing the superelastic behavior of these alloys under cyclical tensile loading are summarized with attention to the effects of annealing temperature, strain rate, and cyclical training on the stress-strain hysteresis, maximum recoverable strain and equivalent viscous damping.

APA, Harvard, Vancouver, ISO, and other styles

21

Lockman, Zainovia. "Surface oxidation epitaxy of (100) <001> nickel and nickel-based alloys." Thesis, Imperial College London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.407610.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Larson, Christopher M. "The corrosion of Ni₃Si alloys in sulfuric acid." Diss., Rolla, Mo. : Missouri University of Science and Technology, 2009. http://scholarsmine.mst.edu/thesis/pdf/Larson_09007dcc8064d372.pdf.

Full text

Abstract:

Thesis (M.S.)--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 April 27, 2009) Includes bibliographical references (p. 67-68).

APA, Harvard, Vancouver, ISO, and other styles

23

Child, Daniel. "Corrosion-fatigue interactions of high-temperature nickel alloys." Thesis, Loughborough University, 2012. https://dspace.lboro.ac.uk/2134/9732.

Full text

Abstract:

Corrosion and fatigue aspects of high temperature turbine components made from Alloy 720Li and RR1000 have been studied with a view to understanding the potential failure mechanisms occurring in these materials. Understanding of such failure mechanisms is important in order to make safety improvements and significant cost savings by reducing engine downtime. Some exservice discs currently exhibit pit-like features at a specific location on the firtree lobes, which potentially may lead to more serious alloy fissuring. Shot peening is currently employed to improve fatigue resistance at the surface of components. This work aims to fully characterise these pits and fissure features in addition to shot peening, and the components in general, using advanced analytical techniques, in order that the failure mechanism(s) can be determined and mitigated against.

APA, Harvard, Vancouver, ISO, and other styles

24

Yang, Iuan-Jou. "Passivity and localized corrosion of nickel-based alloys." Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293886.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Vassiliou, George E. "The erosion-corrosion behaviour of copper-nickel alloys." Thesis, University of Glasgow, 2001. http://theses.gla.ac.uk/2458/.

Full text

Abstract:

The research focuses on an investigation of the erosion-corrosion behaviour of Cu-Ni-base alloys in aqueous environments. The principal objectives of the research were to examine the fundamental mechanisms of the erosion-corrosion attack. The work was focused on a standard Cu-10%Ni alloy that is used extensively in a variety of marine industries and on Marinel alloy, which is a high strength precipitation-hardened copper-nickel alloy. Erosion-corrosion tests were carried out for exposure times up to 72 hours, in a solid free 3.5% NaCl solution impinging at velocities of 2.38-86 m/sec, (Re=4500-86000), at temperatures of 19°C and 35°C. The overall erosion-corrosion behaviour and the direct corrosion component were monitored using gravimetric and electrochemical-monitoring techniques. Contributes from mechanical erosions were assessed by cathodically protecting specimens under impingement conditions. The research also considered the influence of various parameters such as temperature, time, velocity, salinity variations, and impingement angle. The extent and morphology of material deterioration and protective film formation under various environmental conditions were assessed, utilizing surface profiling equipment and light optical and scanning electron microscopy. The work has quantified the complex contributions of corrosion, erosion and synergy to the overall erosion-corrosion material loss. An important finding was the substantial superior erosion-corrosion resistance of Marinel compared to the standard Cu-10%Ni, with interesting effects of impinging velocity and time of exposure being observed. Also this work provided some clear evidence of significant potential benefits in terms of erosion-corrosion resistance, obtained by the exposure of Marinel at the elevated temperature.

APA, Harvard, Vancouver, ISO, and other styles

26

CORTEZ, ORFELINDA AVALO. "SYNTHESIS AND CHARACTERIZATION OF NANOSTRUCTURED IRON-NICKEL ALLOYS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2008. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=12975@1.

Full text

Abstract:

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
Oxido de níquel e hematita nanoestruturadas foram sintetizadas a partir da decomposição térmica de nitrato de níquel hexahidratado e nitrato férrico nonahidratado respectivamente, na faixa de temperatura de 350-450°C com variações no tempo reacional. Os tamanhos de cristalito do NiO e Fe2O3 foram estimados a partir dos difractogramas de Difração de Raios-X (XRD) utilizando os software PowderCell e Topas. Foi observado que o tamanho de cristalito varia em função da temperatura de sínteses. O resultado mais significante foi observado nos cristalitos de NiO os quais aumentam de 31 nm (T=350°C, 3hr) a 98 nm (T=450°C, 5hr). Foram realizados estudos cinéticos da redução NiO e Fe2O3 por hidrogênio na faixa de temperatura de 250-600°C. Ligas ferroníquel nanoestruturadas com composições FexNi100-x (x = 25, 50, and 75 w%) têm sido preparadas com sucesso por decomposição térmica de nitratos (formação de óxidos) e posterior redução com hidrogênio a 700ºC (formação das ligas). As ligas Fe-Ni, caracterizadas por difração de raios-X mostraram tamanhos de cristalito da ordem de 25nm. A fase rica em Ni, liga Fe25Ni75, apresentou uma estrutura γ(FCC). A liga Fe50Ni50 apresentou a existência de uma estrutura tetragonal. A fase rica em Fe, liga Fe75Ni25, contém uma mistura de fases α(BCC) e γ(FCC). A coexistência das fases e atribuída à segregação de fases que acontece nestas ligas como resultado da difusão atômica. A partir dos resultados das medições magnéticas efetuadas a 300K, pode-se estabelecer que as ligas Fe-Ni nanoestruturadas tem um comportamento superparamagnético.
Nickel oxide and hematite nanostructured were successfully prepared by thermal decomposition from nickel nitrate hexahydrate and ferric nitrate nonahydrate in the temperature range of 350-450°C with variation of the time. The average crystallite sizes of NiO and Fe2O3 were estimated from X-ray diffraction (XRD) peaks using the PowderCell and Topas software. We observed that the crystallite size changes as a function of synthesis temperature. The significant result was the large size of the resulting NiO crystallites, which increased from 31nm (T=350°C, 3hr) to 98nm (T=450°C, 5hr). Kinetic studies of the reduction of NiO and Fe2O3 by hydrogen in the temperature range 250-600°C have been investigated. Nanostructured Fe-Ni alloys with compositions FexNi100-x (x = 25, 50, and 75 w%) have been successively prepared by thermal decomposition from mixtures of nitrates (formation of oxides) and reduction by hydrogen at 700ºC (formation of alloys). The Fe-Ni alloys, characterized by X-ray diffraction show crystallites sizes about 25nm. The Nirich phase, Fe25Ni75 alloys show the existence of γ(FCC) phase. The Fe50Ni50 alloy show the existence of tetragonal phase. The Fe-rich phase, Fe75Ni25 alloy, contain a mixture of α(BCC) and γ(FCC) phases. The coexistence of these phases is attributed to phase segregation occurring in these alloys as a result of enhanced atomic diffusion. It was inferred from results of magnetic measurements at 300K, that nanostructured Fe-Ni alloys were in a superparamagnetic state.

APA, Harvard, Vancouver, ISO, and other styles

27

Hwang, Il Soon. "Embrittlement mechanisms of nickel-base alloys in water." Thesis, Massachusetts Institute of Technology, 1987. http://hdl.handle.net/1721.1/31011.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Guzowski, John. "Hot Corrosion of Advanced Nickel-Based Disk Alloys." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1366316205.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

Duncan, Adrian. "Cracking in the welding of cupro-nickel alloys." Thesis, Aston University, 1985. http://publications.aston.ac.uk/11871/.

Full text

Abstract:

The problem of variation in weld crack susceptibility caused by small variations in alloy and impurity elements for the 70-30 cupro-nickel alloy has been investigated. Both wrought and cast versions of the alloy have been studied, the main techniques employed being the Varestraint test and weld thermal simulation. In the wrought alloys, cracking has been found to occur mainly in the weld metal, whilst in the cast alloys cracking is extensive in both weld metal and heat affected zone. The previously reported effects of certain impurities (P,S,Si) in increasing cracking have been confirmed, and it has also been shown that Ti and Zr may both have a crack promoting effect at levels commonly found in cupro-nickels, whilst C can interact with several of the other elements investigated to produce a beneficial effect. The testing carried out using the weld thermal simulator has shown that a relationship does exist between hot ductility and weld cracking. In particular, the absence of the peak in ductility in the range 1100°C-900°C on cooling from a temperature near to the solidus is indicative of a highly crack susceptible alloy. Principal practical implications of the investigation concern the relationship of weld metal cracking to alloy composition, especially the level of certain impurities. It would appear that the upper limits permitted by the alloy specifications are unrealistically high. The introduction of lower impurity limits would alleviate the current problems of variability in resistance to cracking during welding.

APA, Harvard, Vancouver, ISO, and other styles

30

Nissley, Nathan Eugene. "Intermediate temperature grain boundary embrittlement in nickel-base weld metals." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1156949345.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Gomez, Villegas M. G. "Electrocrystallization of metals, alloys and polymeric materials." Thesis, Coventry University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384655.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Ghasemi, Hamid-Reza M. R. "Computer simulation of carburization corrosion of nickel-base superalloys." Thesis, Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/76035.

Full text

Abstract:

A computer model for diffusion-controlled internal precipitation was used to simulate the corrosion behavior of Ni-based superalloys in carburizing atmospheres. The model is based on Crank-Nicholson finite difference solution of the diffusion equation. The code also includes the ternary cross diffusion effect due to substitutional alloying elements that are preferentially oxidized. The model can treat two sets of boundary conditions corresponding to the presence or absence of a protective oxide scale. It accounts for internal precipitation of corrosion products whenever thermodynamic solubility limits are exceeded. Up to four different carbides can be treated simultaneously. The solubility product is computed for each reaction and the amount of carbon that reacts is removed from the diffusion process. Under non-protective conditions, the predictions of model were compared to carburization profiles obtained experimentally in H₂-CH₄ environment tests. Results are presented for the formation of Cr, Mo, Ti, W, and Nb carbides in Ni-based superalloys. The predicted corrosion profiles are in qualitative agreement with experimental data.
Master of Science

APA, Harvard, Vancouver, ISO, and other styles

33

Zou, Xiaodong. "Impedance spectroscopy of nickel base superalloys." Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/20307.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Highsmith, Shelby. "Probabilistic fatigue crack life prediction in a directionally-solidified nickel superalloy." Available online, Georgia Institute of Technology, 2004:, 2003. http://etd.gatech.edu/theses/available/etd-04082004-180222/unrestricted/highsmith%5Fshelby%5F200312%5Fms.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Ibañez, Alejandro R. "Modeling creep behavior in a directionally solidified nickel base superalloy." Available online, Georgia Institute of Technology, 2004:, 2003. http://etd.gatech.edu/theses/available/etd-04072004-180026/unrestricted/ibanez%5Falejandro%5Fr%5F200312%5Fphd.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

36

Norfleet, David Matthew. "Sample size effects related to nickel, titanium and nickel-titanium at the micron size scale." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1187038020.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

Rousseau, Thomas. "Modélisation multi-échelle de la modification de structure d'un alliage à base de nickel soumis à de très fortes déformations plastiques en surface." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEC016/document.

Full text

Abstract:

La compréhension des effets du grenaillage ultrasonore sur l’intégrité de surface des composants métalliques représente un enjeu industriel important. Dans le cadre de cette thèse, une modélisation physique multi-échelle de la plasticité cristalline à la DEM (Discrete Element Model) a été développée. Le grenaillage ultrasonore consiste à mettre en mouvement des billes à l’intérieur d’une enceinte par vibration de la sonotrode. Les impacts répétés sur le matériau entraînent un écrouissage en surface, l’établissement de contraintes résiduelles de compression et la formation d’une couche nanostructurée. L’objectif de cette thèse est d’obtenir une meilleure compréhension des mécanismes conduisant à ces modifications sur un alliage à base nickel. Le mouvement des billes obtenu par DEM est relié aux modifications de la microstructure sous impacts via un modèle éléments finis utilisant une loi de plasticité cristalline. Après validation de chaque étape par des mesures expérimentales, le modèle a permis d’étudier l’effet de la quantité de billes utilisées dans le procédé. Ainsi, un nombre croissant de billes induit une augmentation d’impacts en biais de faible vitesse permettant de concentrer les contraintes résiduelles de compression en extrême surface. De plus, les simulations multi-impacts utilisant une loi de plasticité cristalline ont montré que ces impacts en biais engendraient une densité totale de dislocations et un niveau de désorientations élevées pouvant expliquer la fragmentation des grains et la nanostructuration de la surface. Enfin, ces modifications de la microstructure, visibles jusqu’à 300 µm de profondeur, sont en accord avec les profils de dureté obtenus par nano-indentation et les profils de désorientation issus de l’analyse EBSD (Electron BackScatter Diffraction)
Ultrasonic shot peening is widely used to improve mechanical properties of metallic components. Mastering the effects of this surface treatment is a major industrial issue. A physical multi-scale modelling based on crystal plasticity and DEM (Discrete Element Model) was developed in this PhD thesis. This process is performed in a closed chamber where spherical balls are moved by sonotrode vibration. Thousands of impacts induce hardening, residual compressive stress and microstructure modification leading to a nanostructured layer. The aim of this work was to improve our understanding of the mechanisms occurring during this process on nickel-based alloys. Ball motion was computed by DEM and linked to microstructure modifications induced by impacts through a crystal plasticity finite element model. Experimental analyses were performed in order to validate each step of the multi-scale modelling. Then the model was applied to investigate ball quantity effects on peened surface modification. Increasing the number of balls created a larger quantity of low speed oblique impacts which concentrated the residual compressive stress near the surface. Furthermore multi-impacts performed with a crystal plasticity law showed oblique impacts enhanced dislocation storage and disorientations within grains, which could explain the nanostructuration of the peened surface. Moreover, the numerical microstructure modification, observed up to 300 µm in depth, was in agreement with hardness profiles obtained by nanoindentation and disorientation profiles measured by EBSD (Electron BackScatter Diffraction) analysis

APA, Harvard, Vancouver, ISO, and other styles

38

Tan, Geraldine. "Thermomechanical behaviour of NiTi /." Connect to this title, 2004. http://theses.library.uwa.edu.au/adt-WU2005.0111.

Full text

APA, Harvard, Vancouver, ISO, and other styles

39

Kear, Gareth. "Electrochemical corrosion of marine alloys under flowing conditions." Thesis, University of Portsmouth, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369433.

Full text

APA, Harvard, Vancouver, ISO, and other styles

40

Conrad, Heidi A. Golden Teresa Diane. "Electrochemical deposition of zinc-nickel alloys in alkaline solution for increased corrosion resistance." [Denton, Tex.] : University of North Texas, 2009. http://digital.library.unt.edu/ark:/67531/metadc12101.

Full text

APA, Harvard, Vancouver, ISO, and other styles

41

Ravi, Vilupanur Alwar. "Simultaneous chromizing-aluminizing of nickel and nickel base alloys by halide activated pack cementation /." The Ohio State University, 1988. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487597424136616.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Zhou, Ning. "Simulation study of directional coarsening (rafting) of [gamma]' in single crystal Ni-Al." Columbus, Ohio : Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1228152557.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Arslan, Hulya. "Synthesis And Characterization Of Nickel Based Bulk Amorphous Alloys." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/3/12605099/index.pdf.

Full text

Abstract:

The aim of this study is to synthesize and characterize new bulk amorphous alloys in the Ni- based systems. Theoretical studies on the basis of semi-empirical rules and the electronic theory of alloys in pseudopotential approximation has been provided in order to predict the impurity elements that will lead to an increase in the glass forming ability of Ni-based alloy systems. Glass forming ability of ten different compositions of alloys of Ni-Nb, Ni-Fe, Ni-B, Ni-Hf and Ni-Cr was simulated by using FORTRAN programs based on pseudopotential theory. In addition to the binary alloys, ternary alloys, which were formed by addition of 1 at% of third element to these systems, were also simulated. Since ordering energy is an indicator of glass forming ability, theoretical studies allowed to predict the effect of various third elements on the formation of amorphous phase. Furthermore, ordering energies were also used to calculate other parameters important for glass forming ability. In the second part of the study, on the basis of theoretical results, a series of casting experiments were done. Different compositions of Ni-Nb, Ni-Nb-Sn and Ni-Nb-Al alloys were cast in the centrifugal casting machine. Alloys were melted in alumina crucibles and cast into the copper moulds. Characterizations of cast alloys were done by the use of Metallography, SEM, XRD and DSC. Fully amorphous Ni52Nb41Al7 alloy was synthesized in bulk form with 0.8 mm thickness.

APA, Harvard, Vancouver, ISO, and other styles

44

Kan, Nathan Yu-Kwong. "Fatigue failure from internal defects in nickel base alloys." Thesis, University of Portsmouth, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308845.

Full text

APA, Harvard, Vancouver, ISO, and other styles

45

Yi, Xiaodong. "Rapidly solidified magnesium : nickel alloys as hydrogen storage materials." Thesis, University of Birmingham, 2014. http://etheses.bham.ac.uk//id/eprint/5174/.

Full text

Abstract:

Due to high hydrogen capacity, good reversibility and low cost, magnesium hydride is one of the most promising hydrogen storage materials. However, the high desorption temperature and slow hydriding kinetics hinder the application of magnesium hydrides. To improve the hydrogen storage characteristics of magnesium hydrides, many effective treatments have been developed and applied, such as ball milling, melt spinning, alloying with other metals, adding catalysts and using thin film technique. In this work, melt spinning and alloying with Ni were the main sample modification methods used to improve hydrogen storage properties for magnesium hydrides. At the beginning of this project, it was found that it was difficult to repeat the methodology of sample preparation in the literature. Therefore, sample synthesis method was developed after numerous preliminary trials and a series of Mg-Ni alloys were melt-spun successfully. The structural characterization and analysis of hydrogen storage property were performed on the melt-spun Mg-Ni samples in a range of compositions. It was found that a nanocrystalline / amorphous structure was produced by melt spinning, and a metastable intermediate phase, Mg\(_6\)Ni, was discovered in the melt-spun materials. The melt-spun Mg-Ni ribbons exhibited fast kinetics of both absorption and desorption at 300 °C, with a high capacity. Moreover, they exhibited low temperature and even room temperature hydrogen sorption, with slow kinetics.\(\gamma\)-MgH\(_2\) phase, which forms usually under high pressure, has been found in the samples, which probably caused the ambient hydrogen absorption.

APA, Harvard, Vancouver, ISO, and other styles

46

Engwall, Alison Michelle. "Atomistic computer simulation analysis of nanocrystalline nickel-tungsten alloys." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/57674.

Full text

Abstract:

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2009.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 31).
Nanocrystalline nickel-tungsten alloys are harder, stronger, more resistant to degradation, and safer to electrodeposit than chromium. Atomistic computer simulations have previously met with success in replicating the energetic and atomic conditions of physical systems with 2-4nm grain diameters. Here, a new model subjects a vertically thin unique volume containing 3nm or 10nm FCC grains with aligned z axes to a Monte Carlo-type minimization to investigate the segregation and ordering behavior of W atoms. Short-range order is also tracked with the Warren-Cowley parameter, and energetic results are explored as well. It was found that the Ni-W system has a very strong tendency toward SRO. The 10nm models exhibited more robust order at low concentrations, but ordering in the 3nm model was generally more pronounced. At the dilute limit atoms are driven to the grain boundaries, but as the boundaries are saturated intragranular ordered formations increase and may even perpetuate over low-angle grain boundaries. Ordering was also observed within the grain boundaries at all concentrations for both diameters. The 10nm models were saturated at lower concentration, and grain boundary energy was reduced by up to 93%. W atoms preferred to associate with each other as third-nearest neighbors, but at very high concentrations formations with W atoms as second nearest neighbors were also observed.
by Alison Michelle Engwall.
S.B.

APA, Harvard, Vancouver, ISO, and other styles

47

White, H. J. A. "Photoetching of nickel alloys and reclamation of waste products." Thesis, Cranfield University, 1995. http://dspace.lib.cranfield.ac.uk/handle/1826/11044.

Full text

Abstract:

This thesis details a study into the photoetching of nickel alloys with ferric chloride and the reclamation of waste products. Reclamation occurs through the regeneration of the spent etchant and the recovery of the dissolved nickel content. Etchant regeneration is a means by which a constant etching quality can be maintained. The alternative is its replacement with fresh solution and this option entails the disposal of the exhausted solution according to correct legislative procedures. A cost comparison of both processes, was made in the early stage of this work and a model established to represent the economics of regeneration and conventional disposal (ie. not regenerating) based on the amount of nickel etched per annum. Although the dissolved nickel content will not hinder etchant regeneration, it will affect the quality of subsequent etching and the etchant will remain "contaminated". Consequently, its removal must be considered if etchant regeneration is to be implemented. Therefore, in order to establish the economical viability of nickel removal (and etchant regeneration) it was necessary to investigate potential techniques at an experimental level and to determine their technical feasibility first. Cementation and electrodialysis were investigated, the latter proving to be the more successful technique for this application. Through experimentation, it was possible to determine nickel yield data and the associated chemical and power requirements. This information was then used to calculate the 'costs associated with the process in order to extend the original model.

APA, Harvard, Vancouver, ISO, and other styles

48

Highsmith, Shelby Jr. "Probabilistic fatigue crack life prediction in a directionally-solidified nickel superalloy." Thesis, Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/5410.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Jamison, Jay Dee. "Modeling of thermal and mechanical effects during friction stir processing of nickel-aluminum bronze." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Sep%5FJamison.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

50

Ibanez, Alejandro R. "Modeling creep behavior in a directionally solidified nickel base superalloy." Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/5353.

Full text

APA, Harvard, Vancouver, ISO, and other styles

We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!