To see the other types of publications on this topic, follow the link: Aluminum 2024.
Dissertations / Theses on the topic 'Aluminum 2024'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Aluminum 2024.'
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
Cai, Hong. "Microbiologically influenced corrosion and titanate conversion coatings on aluminum alloy 2024-T3 /." View online ; access limited to URI, 2006. http://0-wwwlib.umi.com.helin.uri.edu/dissertations/dlnow/3225314.
Full text
2
Akhtar, Anisa Shera. "Surface science studies of conversion coatings on 2024-T3 aluminum alloy." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/1713.
Full textAbstract:
The research in this thesis aims to develop new mechanistic knowledge for coating processes at 2024-Al alloy surfaces, ultimately to aid the design of new protective coatings. Coatings formed by phosphating, chromating, and permanganating were characterized especially by scanning Auger microscopy (SAM), X-ray photoelectron spectroscopy, and scanning electron microscopy . The objective was to learn about growth (nm level) as a function of time for different coating baths, as well as a function of lateral position across the different surface microstructural regions, specifically on the μm-sized Al-Cu-Mg and Al-Cu-Fe-Mn particles which are embedded in the alloy matrix . The research characterizes coating thickness, composition, and morphology.
The thesis emphasizes learning about the effect of different additives in zinc phosphating baths . It was found that the Ni²⁺ additive has two main roles : first, the rate of increase in local solution pH is limited by the slower kinetics of reactions involving Ni²⁺ compared to Zn²⁺, leading to thinner zinc phosphate (ZPO) coatings when Ni²⁺ is present. Second, most Ni²⁺ deposition occurs during the later stages of the coating process in the form of nickel phosphate and a Ni-Al oxide in the coating pores on the alloy surface, increasing the corrosion resistance. Aluminum fluoride precipitates first during the initial stages of the coating process, followed by aluminum phosphate, zinc oxide, and finally ZPO.
When Ni²⁺ is present in the coating solution at 2000 ppm, ZnO predominates in the coating above the A-Cu-Fe-Mn particle while ZPO dominates on the rest of the surface. The Mn²⁺ additive gives a more even coating distribution (compared with Ni²⁺) across the whole surface. The Mn²⁺ -containing ZPO coating is similar to the chromate coating in terms of evenness, while there is more coating deposition at the second-phase particles for permanganate coatings. The oxides on the Al-Cu-Fe-Mn and matrix regions are similar before coating, thereby confirming that a variety of observed differences in ZPO coating characteristics at these regions arise from the different electrochemical characteristics of the underlying metals. Upon exposure to a corrosive solution, the ZPO coating provides more protection to the second-phase particles compared to the matrix.
3
Wang, Xi. "Corrosion Protection of Aluminum Alloy 2024-T3 by Al-Rich Primer." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1557143060015145.
Full text
4
Gujarathi, Kedar Kanayalal. "Corrosion of aluminum alloy 2024 belonging to the 1930s in seawater environment." [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-3002.
Full text
5
GUO, YANG. "A Study of Trivalent Chrome Process Coatings on Aluminum Alloy 2024-T3." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1308166499.
Full text
6
Patel, Rishikumar M. "Investigating the Mechanical Behavior of Conventionally Processed High Strength Aluminum Alloy 2024." University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1523106869575194.
Full text
7
Vasudevan, Satish. "AN INVESTIGATION OF QUASI-STATIC BEHAVIOR, HIGH CYCLE FATIGUE AND FINAL FRACTURE BEHAVIOR OFALUMINUM ALLOY 2024 AND ALUMINUM ALLOY 2219." Akron, OH : University of Akron, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=akron1193668130.
Full textAbstract:
Thesis (M.S.)--University of Akron, Dept. of Mechanical Engineering, 2007."December, 2007." Title from electronic thesis title page (viewed 02/23/2008) Advisor, T. S. Srivatsan; Faculty readers, Craig Menzemer, Amit Prakash; Department Chair, Celal Batur; Dean of the College, George K. Haritos; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.
8
Silva, José Wilson de Jesus [UNESP]. "Efeito dos oxi-ânions do grupo VIB sobre a corrosão aquosa das ligas Al(2024) e Al(7050) utilizadas na indústria aeronaútica." Universidade Estadual Paulista (UNESP), 2003. http://hdl.handle.net/11449/97122.
Full textAbstract:
Made available in DSpace on 2014-06-11T19:28:35Z (GMT). No. of bitstreams: 0
Previous issue date: 2003Bitstream added on 2014-06-13T20:37:40Z : No. of bitstreams: 1
silva_jwj_me_guara.pdf: 1820882 bytes, checksum: 7e96fbad2b277d2b628c44604b9cf46d (MD5)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Foram caracterizados os comportamentos eletroquímicos e avaliadas as resistências à corrosão das ligas aeronáuticas 2024-T351 e 7050-T7451 em soluções aquosas de cloreto contendo cromato, molibdato e tungstato. Foram realizados ensaios de corrosão não-eletroquímicos de imersão prolongada acompanhados de análise metalográfica de superfície por microscopia óptica e identificação dos produtos de corrosão por difratometria de raios-X. A análise quantitativa de superfícies das ligas após a imersão, indica que os pites formados têm áreas médias similares. Os pites são mais largos do que profundos e de geometria, predominantemente, cônica ou quase-cônica e irregular. Em todos os produtos de corrosão de cada liga foi encontrado hidróxido de alumínio, em suas diferentes formas cristalinas. Medidas de perda de dureza, como uma conseqüência da deterioração superficial, também foram determinadas. Além disso, ensaios eletroquímicos como medidas de potencial em circuito aberto, curvas de polarização e voltametria cíclica complementaram este estudo. Em meio aerado os resultados obtidos mediante medidas eletroquímicas são consistentes com aqueles obtidos nos ensaios de imersão, em particular o efeito do CrO42- e do MoO42-. O WO42- mostrou-se agressivo em períodos prolongados de imersão. Apesar dos ensaios revelarem uma redução parcial de MoO42- em ambas as ligas, o efeito desse oxi-ânion parece ser diferente sobre cada liga. Em meio desaerado as ligas apresentam passivação em todos os eletrólitos. A adição dos oxi-ânions não modificou significativamente o potencial de pite para a liga 7050, enquanto que para a liga 2024 ele foi deslocado levemente para valores mais positivos.
It has been characterized the electrochemical behavior and evaluated the 2024-T351 and 7050-T7451 aircraft alloys corrosion resistance in chloride aqueous solutions containing chromate, molybdate and tungstate. It has been carried out non-electrochemical long immersion corrosion testings accompanied by surface metalography analysis achieved by light microscopy and corrosion products identification by X-ray difratometry. Surfaces quantitative analysis upon the alloys after immersion, indicates that formed pits have similar average area. Pits are widther than deeper and own predominantly a conical or quasi-conical and irregular geometry. In all corrosion products of each alloy it has been found aluminum hydroxide in its different crystalline ways. Hardness loss measurements have also been determined. In addition, electrochemical testings such as open circuit potential measures, polarization curves and cyclical voltammetry have completed this study. In aerated means the obtained results before electrochemical mesurements are similar to those obtained in the immersion tests, in particular CrO42- and MoO42- effects. WO42- has been found to be aggressive in very long immersion period. Though tests display a MoO42- partial reduction in both alloys, this oxi-anion effect seems to be different upon each alloy. In de-aerated means alloys present passivation in all eletrolytes. Oxi-anion addition has not changed significantly pit potential for 7050 alloy, while for 2024 alloy it has been dislocated, slightly, for more positive values.
9
Mann, Philip. "Evaluation of surface modifications introduced by shot peening of aluminum alloy 2024-T351." Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=123117.
Full textAbstract:
Shot peening is a cold working mechanical deformation process consisting of bombarding a metallic surface with small spherical media, called shots, at velocities commonly in the range of 10 to 100 m/s. Upon impact, the shots generate a near-surface deformed layer containing local hardening as well as compressive residual stresses, resulting in an improved fatigue resistance. However, the dependence of shot velocity and percentage of the total area covered by shot impacts on the surface modification introduced by shot peening are not well understood.The hardness and residual stress profiles beneath shot peened surfaces were investigated using nanoindentation experiments for the situations of three different average shot velocities, corresponding to 35 m/s, 54 m/s and 66 m/s, and two surface coverages, corresponding to a single shot peening impingement and full coverage (100%). For the situation (i) of a single impingement, a new polishing procedure was developed allowing locating an isolated single impingement, verifying that the impingement was produced by a shot that impacted at normal incidence, as well as preparing the surface such that nanoindentation could be performed on the impingement's cross-section. It was demonstrated that both hardness and compressive residual stresses increased with an increase in shot velocity. The experimental residual stress results were compared to those from numerical simulations that utilized the same peening parameters as the experiments. It was observed that the experimental results demonstrated similar behavior and were of the same order of magnitude as those predicted numerically. The main difference was that the experimental results demonstrated a maximum compressive residual stress that was independent of shot velocity.For the situation (ii) of full coverage, channelling contrast imaging in a scanning electron microscope revealed that there were recrystallized grains adjacent to the shot peened edge. Additionally, the hardness and compressive residual stresses were observed to increase with an increase in shot velocity. Similarly to the single impingement, the location of maximum compressive residual stress was independent of shot velocity.Le grenaillage est un procédé de déformation mécanique consistant à bombarder une surface métallique ductile avec de petits billes sphériques à des vitesses élevées (10 à 100 m/s). Lors de l'impact, les billes génèrent l'apparition d'une zone déformée en surface, caractérisée par un durcissement relativement important ainsi qu'un champ de contraintes résiduelles de compression, ce qui entraîne une meilleure résistance à la fatigue. Cependant, l'effet de la vitesse d'impact de la bille et de la couverture de surface sur la modification des propriétés de surface induit par le grenaillage ne sont pas bien compris.Dans cette étude, la dureté et les contraintes résiduelles ont été étudiées en utilisant des expériences de nanoindentation pour les situations suivantes: trois vitesses de billes différentes correspondant à 35 m/s, 54 m/s et 66 m/s, ainsi que deux couvertures de surface correspondant à un seul impact et à une couverture complète (100%). Pour la situation (i) de l'étude d'un unique impact, une nouvelle procédure de polissage a été développée permettant de localiser un impact isolé. Cette procédure permet de préparer la surface de telle sorte que la nanoindentation peut être effectuée sur la section transversale de l'impact et permet de vérifier que l'impact a été produit par une bille frappant la surface avec une incidence normale. Il a été observé que la dureté et les contraintes résiduelles de compression augmentent avec une augmentation de la vitesse de la bille. Les résultats expérimentaux de contraintes résiduelles ont été comparés à ceux d'une simulation numérique en utilisant les mêmes paramètres expérimentaux de grenaillages. Il a été observé que les résultats expérimentaux montrent un comportement similaire et sont du même ordre de grandeur que ceux obtenus par simulation numérique. La principale différence est que les résultats expérimentaux ont montré une contrainte résiduelle de compression maximale étant indépendante de la vitesse de la bille.Pour la situation (ii) d'une couverture complète et à l'aide du procédé de microscopie électronique à balayage, nous avons observé un raffinement des grains adjacents à la surface grenaillée. En outre, nous avons observé que la dureté et les contraintes résiduelles de compression augmentaient avec une augmentation de la vitesse de la bille. De même que pour l'impact isolé, la localisation des contraintes résiduelles de compression maximale était indépendante de la vitesse de la bille.
10
Lopez-Garrity, Omar A. "Corrosion Inhibition Mechanisms of Aluminum Alloy 2024-T3 by Selected non-Chromate Inhibitors." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1372077968.
Full text
11
Seidt, Jeremy Daniel. "Plastic Deformation and Ductile Fracture of 2024-T351 Aluminum under Various Loading Conditions." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1268148067.
Full text
12
Chilukuri, Anusha. "Corrosion Inhibition by Inorganic Cationic Inhibitors on the High Strength Aluminum Alloy, 2024-T3." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1343784869.
Full text
13
Silva, José Wilson de Jesus. "Efeito dos oxi-ânions do grupo VIB sobre a corrosão aquosa das ligas Al(2024) e Al(7050) utilizadas na indústria aeronaútica /." Guaratinguetá : [s.n.], 2003. http://hdl.handle.net/11449/97122.
Full textAbstract:
Resumo: Foram caracterizados os comportamentos eletroquímicos e avaliadas as resistências à corrosão das ligas aeronáuticas 2024-T351 e 7050-T7451 em soluções aquosas de cloreto contendo cromato, molibdato e tungstato. Foram realizados ensaios de corrosão não-eletroquímicos de imersão prolongada acompanhados de análise metalográfica de superfície por microscopia óptica e identificação dos produtos de corrosão por difratometria de raios-X. A análise quantitativa de superfícies das ligas após a imersão, indica que os pites formados têm áreas médias similares. Os pites são mais largos do que profundos e de geometria, predominantemente, cônica ou quase-cônica e irregular. Em todos os produtos de corrosão de cada liga foi encontrado hidróxido de alumínio, em suas diferentes formas cristalinas. Medidas de perda de dureza, como uma conseqüência da deterioração superficial, também foram determinadas. Além disso, ensaios eletroquímicos como medidas de potencial em circuito aberto, curvas de polarização e voltametria cíclica complementaram este estudo. Em meio aerado os resultados obtidos mediante medidas eletroquímicas são consistentes com aqueles obtidos nos ensaios de imersão, em particular o efeito do CrO42- e do MoO42-. O WO42- mostrou-se agressivo em períodos prolongados de imersão. Apesar dos ensaios revelarem uma redução parcial de MoO42- em ambas as ligas, o efeito desse oxi-ânion parece ser diferente sobre cada liga. Em meio desaerado as ligas apresentam passivação em todos os eletrólitos. A adição dos oxi-ânions não modificou significativamente o potencial de pite para a liga 7050, enquanto que para a liga 2024 ele foi deslocado levemente para valores mais positivos.Abstract: It has been characterized the electrochemical behavior and evaluated the 2024-T351 and 7050-T7451 aircraft alloys corrosion resistance in chloride aqueous solutions containing chromate, molybdate and tungstate. It has been carried out non-electrochemical long immersion corrosion testings accompanied by surface metalography analysis achieved by light microscopy and corrosion products identification by X-ray difratometry. Surfaces quantitative analysis upon the alloys after immersion, indicates that formed pits have similar average area. Pits are widther than deeper and own predominantly a conical or quasi-conical and irregular geometry. In all corrosion products of each alloy it has been found aluminum hydroxide in its different crystalline ways. Hardness loss measurements have also been determined. In addition, electrochemical testings such as open circuit potential measures, polarization curves and cyclical voltammetry have completed this study. In aerated means the obtained results before electrochemical mesurements are similar to those obtained in the immersion tests, in particular CrO42- and MoO42- effects. WO42- has been found to be aggressive in very long immersion period. Though tests display a MoO42- partial reduction in both alloys, this oxi-anion effect seems to be different upon each alloy. In de-aerated means alloys present passivation in all eletrolytes. Oxi-anion addition has not changed significantly pit potential for 7050 alloy, while for 2024 alloy it has been dislocated, slightly, for more positive values.
Orientador: Eduardo Norberto Codaro
Coorientador: Roberto Zenhei Nakazato
Banca: Luis Rogerio de Oliveira Hein
Banca: Gilberto Luis Jardim Pinto da Silva
Mestre
14
Huang, I.-Wen Evan. "Uniform Corrosion and General Dissolution of Aluminum Alloys 2024-T3, 6061-T6, and 7075-T6." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1469105977.
Full text
15
Costa, Douglas Henrique da Silva [UNESP]. "Estudo do efeito do processo de shot peening na taxa de propagação de trinca por fadiga na liga aeronáutica 2024 - T3." Universidade Estadual Paulista (UNESP), 2015. http://hdl.handle.net/11449/123234.
Full textAbstract:
Made available in DSpace on 2015-05-14T16:53:10Z (GMT). No. of bitstreams: 0
Previous issue date: 2015-01-20Bitstream added on 2015-05-14T16:59:18Z : No. of bitstreams: 1
000824425.pdf: 5119036 bytes, checksum: d2208b40c21a089b314a4455cfc48518 (MD5)Este trabalho tem por finalidade avaliar o efeito do processo de shot peening na taxa de propagação de uma trinca por fadiga já existente. O shot peening é um processo de trabalho a frio, que consiste no jateamento repetitivo com microesferas de aço, cerâmica ou vidro, na superfície de uma peça, produzindo encruamento e induzindo tensões residuais compressivas nas superfícies tratadas. Devido a isso, o shot peening tem-se mostrado um método bastante eficiente para dificultar o início e a propagação de uma trinca por fadiga a partir da superfície do material, melhorando a sua resistência à fadiga. Contudo, estudos de seu efeito sobre uma trinca já existente são pouco conhecidos. Corpos de prova do tipo CT, para a liga aeronáutica de alumínio 2024 - T3, foram inicialmente trincados por fadiga e, em seguida, submetidos ao processo de shot peening em ambos os lados. Após o tratamento, os ensaios foram reiniciados nas mesmas condições. Os ensaios foram realizados com amplitude constante em duas espessuras de corpos de prova e duas razões de carga, R, para analisar possíveis efeitos do estado de tensão na ponta da trinca nos resultados. Duas intensidades de shot peening foram utilizadas para cada valor de R ou espessura analisada. Também foram estudadas duas regiões de aplicação do processo de shot peening (atrás e em volta da ponta da trinca) em dois tamanhos de trincas. Curvas comparativas do comportamento da taxa de propagação de trincas por fadiga, mostrando a influência de cada um dos parâmetros descritos, são apresentadas, e suas diferenças, discutidas. Os resultados encontrados mostram que o processo de shot peening, quando realizado em um tamanho de trinca em pleno estágio II de propagação, apresenta maior influência quando aplicado atrás da ponta da trinca, com menor intensidade, em corpos de prova em estado ... (Resumo Completo, clicar acesso eletrônico abaixo)
This work focuses to evaluate the effect of the shot peening process in the propagation rate of a fatigue crack already existing. The shot peening is a cold working process, which consists of repetitive blasting with steel shot, ceramic or glass, the surface of a workpiece, producing hardening and inducing compressive residual stresses on the treated surfaces. Because of this, shot peening has proved a very efficient method for hindering the initiation and propagation of a fatigue crack from the surface of the material, improving its fatigue strength. However, studies of its effect on an already existing crack are little known. Specimens of type CT to the aeronautics aluminum alloy 2024 - T3, were initially cracked by fatigue and then subjected to shot peening process on both sides. After treatment, the tests were resumed under the same conditions. Tests were carried out with constant amplitude in two thicknesses of specimens and two load ratios, R, to analyze possible effects of stress state on the crack tip results. Two shot peening intensities were used for each R value or thicknesses analyzed, and were also studied two application regions of shot peening process (behind and around the crack tip) in two sizes of cracks. Comparative curves of the fatigue crack propagation rate, showing the influence of each of the parameters described are shown, and their differences discussed. The results show that the shot peening process, when performed in a crack size in full stage II propagation, has greater influence when applied behind the crack tip, with lower intensity, in the specimens in plane stress state and lower load ratio. For crack lower (close to the stage I of propagation), the shot peening process applied behind the crack tip induced delay in their propagation rate in all conditions studied. The delay effect on fatigue crack propagation rate ... (Complete abstract click electronic access below)
16
ASHIRGADE, AKSHAY A. "ENVIRONMENTALLY-COMPLIANT NOVOLAC SUPERPRIMERS FOR CORROSION PROTECTION OF ALUMINUM ALLOYS." University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1153245386.
Full text
17
Gordon, Matthew. "A Nacreous Self-Assembled Nanolaminate for Corrosion Resistance on 2024-Al Alloy." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/33548.
Full textAbstract:
Nanometer thick layers of clay and polymer were formed on mica, silicon, and aluminum 2024-T3 alloy using alternating solutions of positively and negatively charged polymer and clay, respectively. Atomic force microscopy was used to observe the morphology of the composite films on mica and silicon. It was found that solution concentrations of clay above 0.02 weight percent lead to the uncontrolled deposition of clay platelets on the substrateâ s surface. By using solution concentrations of clay above 0.02 weight percent and ultrasonic agitation together it is possible to deposit a uniform monolayer of clay platelets on a mica substrate in £ 20 seconds. Ultrasonic agitation also produced crude patterns of montmorillonite platelets.
Thin films of poly(diallydimethylammonium chloride) (PDDA) were made using concentrations ³ 2 weight percent of PDDA. It was found that the PDDA formed several unusual morphologies. Spherulites of PDDA were observed with AFM and the glass transition temperature of high molecular weight PDDA was measured using differential scanning calorimetry (DSC).
Circular regions of positive charge were discovered on silicon wafers provided by three different sources. These areas of charge have never been reported in literature, but can easily be detected by placing wafers into solutions containing negatively or positively charged solutions of clay or polymer, respectively. The exact nature of these charged regions is unknown, but it is hypothesized that impurities on silicon wafers create the circular regions of positive charge.
ISAM films made of a polyamide salt and a synthetic clay, Laponite RD®, demonstrated significant corrosion resistance on 2024-T3 Al alloys after 168 hours of salt spray testing. The ISAM films offered corrosion protection only if there was a significant layer of underlying surface oxide present, however. It was found that ISAM deposited films of polyarylic acid (PAA) and polyallylamine hydrochloride (PAH) may offer some corrosion resistance on 2024-T3 Al alloys, but these filmsâ corrosion resistance is severely hampered by the presence of Cl- in the PAH solution.
Funding from this project was gratefully received from the Materials Science and Engineering Department at Virginia Tech; Luna Innovations Inc; the American Chemical Society / Petroleum Research Fund #34412-G5 and the Environmental Protection Agency Contract #68-D-00-244.Master of Science
18
Saraloglu, Ebru. "Effect Of Ecap And Subsequent Heat Treatments On Microstructure And Mechanical Properties Of 2024 Aluminum Alloy." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12609811/index.pdf.
Full textAbstract:
Severe plastic deformation (SPD) results in ultra-fine grain sizes in metals and alloys. Equal channel angular pressing (ECAP) is one of the special SPD methods aiming to introduce high plastic strains into the bulk materials without changing their cross section. ECAP results in improvement in hardness and strength while still satisfying acceptable ductility level. The combined effects of ECAP and subsequent heat treatments, i.e. post-aging and post-annealing, on the microstructure and hardness of the 2024 aluminum alloy were investigated. An ECAP die with 120˚
channel angle was constructed. Subgrain formation, increase in dislocation density and dislocation tangling were observed after ECAP, and subgrain growth was detected after post annealing. The specimens revealed higher hardness values after ECAP at room temperature, and further increase in hardness was observed following post-aging at 80&
#730
C, 100&
#730
C and 190&
#730
C. Effect of the aging temperature on the deformed specimens was investigated, and the aging behaviors of the severely deformed and undeformed samples at 190&
#730
C were compared.
19
Gavelius, Marianne, and Karin Andersson. "Surface Treatment for Additive Manufactured Aluminum Alloys." Thesis, Linköpings universitet, Molekylär ytfysik och nanovetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-169027.
Full textAbstract:
Manufacturing of aircraft parts is often complex and time-consuming, which has led to an increased interest in new manufacturing technologies in the Swedish industry such as additive manufacturing (AM). Additive manufacturing techniques could be a solution to meet the aircrafts’ demand since it contributes to an efficient manufacturing and allows a just-in-time production of complex metal parts in their final shape. However, the use of AM aluminum for aircraft applications is in a development phase and no surface treatment process exists. Thereby, it is of high interest to further investigate surface treatments for AM alloys. Currently at Saab AB, conventional aluminum alloys are generally anodized in tartaric sulphuric acid (TSA) to improve the corrosion resistance and adhesion properties of the metal. On the behalf of Saab AB, there is also an interest in establishing powder coating as a surface treatment. This master thesis’ purpose is to investigate the anodizing and adhesion properties for the two additive manufacturing alloys - AlSi10Mg and ScalmalloyⓇ, and compare it with the conventionally produced Al alloy 2024-T3. The anodization and the powder coating is examined by using following characterization techniques: profilometry, light microscopy, scanning electron microscopy and contact angle measurements. The results from the experimental part indicated successful anodizations for all the alloys and good adhesion properties for powder coating. This research is a first step in contributing to a better understanding of the anodic coating and adhesion properties for the AM samples ScalmalloyⓇ and AlSi10Mg
20
Paiva, Sergio Ricardo de. "Efeito da anisotropia na propagação da deformação induzida em ligas 2024 termicamente tratadas." Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/152874.
Full textAbstract:
Submitted by SERGIO RICARDO DE PAIVA null (sergio.paiva@embraer.com.br) on 2018-03-01T23:18:05Z
No. of bitstreams: 1
Dissertação Sergio Paiva_Versão Final_F_Alterações.pdf: 4152807 bytes, checksum: bd7266ab07460bb304ec051893e2dce2 (MD5)Approved for entry into archive by Pamella Benevides Gonçalves null (pamella@feg.unesp.br) on 2018-03-02T12:14:34Z (GMT) No. of bitstreams: 1 paiva_sr_me_guara.pdf: 4152807 bytes, checksum: bd7266ab07460bb304ec051893e2dce2 (MD5)
Made available in DSpace on 2018-03-02T12:14:34Z (GMT). No. of bitstreams: 1 paiva_sr_me_guara.pdf: 4152807 bytes, checksum: bd7266ab07460bb304ec051893e2dce2 (MD5) Previous issue date: 2018-01-26
O processo de rebitagem é largamente utilizado na indústria aeronáutica para fabricação de fuselagens de aviões. Durante esse processo deformações locais são introduzidas nas estruturas por meio da expansão dos rebites devido sua conformação. A deformação plástica causa uma expansão no rebite e consequentemente na estrutura circundante onde o mesmo foi inserido. Este trabalho tem como objetivo analisar o efeito da anisotropia na propagação da deformação induzida em corpos de prova de ligas 2024 que passaram pelo processo de rebitagem, em chapas de alumínio termicamente tratadas. O experimento avaliou como a geometria do grão, relacionadas ao tamanho e forma dos mesmos, assim como o efeito do tratamento térmico, influenciam na expansão diametral. Foram empregados corpos de prova de liga de alumínio 2024 com tratamento térmico T3 e TO, comumente utilizadas pela indústria aeronáutica, em diferentes direções de grãos, longitudinal e transversal, onde foram cravados rebites e avaliado o alongamento dos corpos de prova pelo efeito da rebitagem. Os resultados obtidos comprovam que a anisotropia exerce uma influência significativa no fator expansão e que a deformação plástica na direção transversal de laminação foi aproximadamente 60% maior que na direção de laminação para os dois tratamentos térmicos analisados. Também foi constatado que o tratamento térmico do material influencia no fator expansão. Verificou-se que a expansão dos corpos de prova recozidos foi o dobro nas direções transversal e longitudinal quando comparados com os corpos de prova de condição envelhecida
The riveting process is wide used at Aerospace industry during airplane fuselage construction. During this process, local deformations are introduced in the structures by the rivet expansion, due the plastic deformation. The plastic deformation makes the rivet expand inside the hole and consequently, the structure around the rivet expand too. The goal of this research is to analyses the anisotropy effect in the squeezing force propagation in specimens of 2024 alloys that were submitted to the riveting process, in aluminum plates heated treatment. The research analyzed the grain geometry related to size and form, and how the heat treatment effect influences the hole diameter expansion. It was used specimens of aluminum alloy 2024 T3 and TO, commonly used in aerospace industry, in different grains directions, longitudinal and transversal. Rivets were installed and the specimen stretching was analyzed. The results prove that the anisotropy have a significative influence in the expansion factor, the plastic deformation in the transversal rolled direction was about 60% bigger than rolled direction for the two heat treatment analyzed. Also, it was verified that the material heat treatment influences the factor expansion. According the results the expansion in the relieved specimens condition were the double in the transversal and longitudinal direction than the aging specimens condition
21
Shivalli, Praveen Smith Bert. "The effect of dents on fatigue life and fatigue crack growth of aluminum 2024-T3 bare sheet." Diss., A link to full text of this thesis in SOAR, 2006. http://soar.wichita.edu/dspace/handle/10057/681.
Full textAbstract:
Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering."December 2006." Title from PDF title page (viewed on Sept. 24, 2007). Thesis adviser: Bert Smith. Includes bibliographic references (leaves 62-64).
22
Beal, Roger Zack. "A study comparing changes in loading conditions of an extended service life system using aluminum 2024-T351." Thesis, The University of Utah, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1569706.
Full textAbstract:
The current fiscally austere environment prevalent in the military and industry is driving extreme measures to save money. In the United States Air Force, this has driven enormous efforts to trim sustainment spending on extended life aircraft. The challenge to the aerospace engineer is to ensure flight safety in the midst of this economic pressure.
One method of cutting costs is to increase the time an aircraft is in service by delaying the point when the aircraft is taken out of service for depot maintenance. To ensure flight safety, in depth fatigue and fracture analysis needs to be accomplished to assess increasing the inspection interval.
The purpose of this study was to determine the sensitivity of Aluminum 2024-T351 alloy, a common material used in tension dominated aerospace applications, to two different loading spectra—one that is aggressive and the other that is benign. This was accomplished by conducting five different combinations of the two spectra, developing computer simulations using the AFGROW software and comparing with the measured data. The results showed that the material demonstrated significantly different behavior between the two spectra. These results provide a valuable tool for the aerospace engineer for fatigue life prediction and inspection interval evaluation.
23
Fang, Yan. "Simulation, measurement and Image analysis of corrosion initiation and growth rate for Aluminum 2024 and Steel 304." VCU Scholars Compass, 2011. http://scholarscompass.vcu.edu/etd/2569.
Full textAbstract:
Abstract SIMULATION, MEASUREMENT AND IMAGE ANALYSIS OF CORROSION INITIATION AND GROWTH RATE OF ALUMIUM 2024 AND STEEL 304 By Yan Fang, MS A thesis submitted in partial fulfillment of the requirements for the degree of M.S. of Mechanical and Nuclear Engineering at Virginia Commonwealth University. Virginia Commonwealth University, 2011 Major Director: Dr. Brian Hinderliter, Ph. D Associate professor, Mechanical and Nuclear Engineering Time: 11 a.m. Place: Room E3210 Engineering East Hall Date: Friday August 12, 2011 Corrosion initiation and growth rate are important properties in maintaining structural integrity, especially for surface and pit corrosion of common infrastructure and transportation metals. In this study, the surface corrosion pit initiation and growth rate on Aluminum 2024(common aerospace alloy) and Steel 304(common alloy for infrastructure) in different pH solutions was measured and values were analyzed by image analysis over a scheduled time. A MATLAB algorithm was developed for detecting the initiation and growth rate of pits as a function of time. The developed algorithm was validated with simulated specimen as well as experiments conducted corrosion specimen. Based on the result of obtained, the MATLAB algorithm predicts the right trends and power law radial corrosion pit growth rates and should be useful for corrosion initiation and growth predictions in various metals.
24
Costa, Douglas Henrique da Silva. "Estudo do efeito do processo de shot peening na taxa de propagação de trinca por fadiga na liga aeronáutica 2024 - T3 /." Guaratinguetá, 2015. http://hdl.handle.net/11449/123234.
Full textAbstract:
Orientador: Marcelo Augusto Santos TorresBanca: Antonio Jorge Abdalla
Banca: Carlos Antonio Reis Pereira Baptista
Resumo: Este trabalho tem por finalidade avaliar o efeito do processo de shot peening na taxa de propagação de uma trinca por fadiga já existente. O shot peening é um processo de trabalho a frio, que consiste no jateamento repetitivo com microesferas de aço, cerâmica ou vidro, na superfície de uma peça, produzindo encruamento e induzindo tensões residuais compressivas nas superfícies tratadas. Devido a isso, o shot peening tem-se mostrado um método bastante eficiente para dificultar o início e a propagação de uma trinca por fadiga a partir da superfície do material, melhorando a sua resistência à fadiga. Contudo, estudos de seu efeito sobre uma trinca já existente são pouco conhecidos. Corpos de prova do tipo CT, para a liga aeronáutica de alumínio 2024 - T3, foram inicialmente trincados por fadiga e, em seguida, submetidos ao processo de shot peening em ambos os lados. Após o tratamento, os ensaios foram reiniciados nas mesmas condições. Os ensaios foram realizados com amplitude constante em duas espessuras de corpos de prova e duas razões de carga, R, para analisar possíveis efeitos do estado de tensão na ponta da trinca nos resultados. Duas intensidades de shot peening foram utilizadas para cada valor de R ou espessura analisada. Também foram estudadas duas regiões de aplicação do processo de shot peening (atrás e em volta da ponta da trinca) em dois tamanhos de trincas. Curvas comparativas do comportamento da taxa de propagação de trincas por fadiga, mostrando a influência de cada um dos parâmetros descritos, são apresentadas, e suas diferenças, discutidas. Os resultados encontrados mostram que o processo de shot peening, quando realizado em um tamanho de trinca em pleno estágio II de propagação, apresenta maior influência quando aplicado atrás da ponta da trinca, com menor intensidade, em corpos de prova em estado ... (Resumo Completo, clicar acesso eletrônico abaixo)
Abstract: This work focuses to evaluate the effect of the shot peening process in the propagation rate of a fatigue crack already existing. The shot peening is a cold working process, which consists of repetitive blasting with steel shot, ceramic or glass, the surface of a workpiece, producing hardening and inducing compressive residual stresses on the treated surfaces. Because of this, shot peening has proved a very efficient method for hindering the initiation and propagation of a fatigue crack from the surface of the material, improving its fatigue strength. However, studies of its effect on an already existing crack are little known. Specimens of type CT to the aeronautics aluminum alloy 2024 - T3, were initially cracked by fatigue and then subjected to shot peening process on both sides. After treatment, the tests were resumed under the same conditions. Tests were carried out with constant amplitude in two thicknesses of specimens and two load ratios, R, to analyze possible effects of stress state on the crack tip results. Two shot peening intensities were used for each R value or thicknesses analyzed, and were also studied two application regions of shot peening process (behind and around the crack tip) in two sizes of cracks. Comparative curves of the fatigue crack propagation rate, showing the influence of each of the parameters described are shown, and their differences discussed. The results show that the shot peening process, when performed in a crack size in full stage II propagation, has greater influence when applied behind the crack tip, with lower intensity, in the specimens in plane stress state and lower load ratio. For crack lower (close to the stage I of propagation), the shot peening process applied behind the crack tip induced delay in their propagation rate in all conditions studied. The delay effect on fatigue crack propagation rate ... (Complete abstract click electronic access below)
Mestre
25
Widener, Christian Aragon Talia George E. "Evaluation of post-weld heat treatments for corrosion protection in friction stir welded 2024 and 7075 aluminum alloys." Diss., Click here for available full-text of this thesis, 2005. http://library.wichita.edu/digitallibrary/etd/2005/d004.pdf.
Full textAbstract:
Thesis (Ph.D.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering."December 2005." Title from PDF title page (viewed on February 8, 2007). Thesis adviser: George Talia. Includes bibliographic references leaves 192-203).
26
Guo, Xiaolei. "Corrosion inhibition of aluminum alloy 2024-T3 based on smart coatings, hybrid corrosion inhibitors, and organic conversion coatings." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1461188604.
Full text
27
Goetze, Paul Aaron. "A Comparative Study of 2024-T3 and 7075-T6 Aluminum Alloys Friction Stir Welded with Bobbin and Conventional Tools." Miami University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=miami1556807142415698.
Full text
28
Sofyan, Nofrijon Bin Imam Gale W. F. "Microstructure and mechanical properties of 2024-T3 and 7075-T6 aluminum alloys and austenitic stainless steel 304 after being exposed to hydrogen peroxide." Auburn, Ala, 2008. http://repo.lib.auburn.edu/EtdRoot/2008/SUMMER/Materials_Engineering/Dissertation/Sofyan_Nofrijon_36.pdf.
Full text
29
André, Natália Manente. "Friction spot joining of aluminum alloy 2024-t3 and carbon-fiber-reinforced polyphenylene sulfide composite laminate with additional pps film interlayer." Universidade Federal de São Carlos, 2015. https://repositorio.ufscar.br/handle/ufscar/8275.
Full textAbstract:
Submitted by Alison Vanceto (alison-vanceto@hotmail.com) on 2016-10-21T11:41:37Z
No. of bitstreams: 1
DissNMA.pdf: 5169564 bytes, checksum: 024c06d911b0aca7d5ad498353cc25ef (MD5)Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-11-08T18:38:42Z (GMT) No. of bitstreams: 1 DissNMA.pdf: 5169564 bytes, checksum: 024c06d911b0aca7d5ad498353cc25ef (MD5)
Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-11-08T18:38:48Z (GMT) No. of bitstreams: 1 DissNMA.pdf: 5169564 bytes, checksum: 024c06d911b0aca7d5ad498353cc25ef (MD5)
Made available in DSpace on 2016-11-08T18:38:54Z (GMT). No. of bitstreams: 1 DissNMA.pdf: 5169564 bytes, checksum: 024c06d911b0aca7d5ad498353cc25ef (MD5) Previous issue date: 2015-11-30
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Friction Spot Joining (FSpJ) is a prize-winning joining technique for hybrid metal-polymer composite structures. This master thesis was devised to investigate the feasibility of FSpJ of metal-composite structures with additional film interlayer. Friction spot joints of aluminum alloy 2024-T3 and carbon-fiberreinforced polyphenylene sulfide laminate composite with additional PPS film interlayer were successfully produced. The highest peak temperature achieved during the joining process was 417°C. DSC analysis demonstrated that the degree of crystallinity decreased for the composite (from 22% to 12%) and increased for the PPS film (from 7% to 27%) after joining. TGA analysis indicated that no extensive thermo-mechanical degradation induced by the joining process occurred. The main bonding mechanisms of FSp joint were identified as macro- and micro-mechanical interlocking, as well as adhesion forces. The process-related microstructural effects were evaluated and correlated to the local mechanical performance of the joining parts through micro and nanohardness. Further, mechanical grinding, sandblasting and plasma activation surface pre-treatments were performed on the composite part to enhance the adhesion between the joining parts. The generated surface features due to the surface pre-treatments were correlated to the mechanical performance of the joints. Sandblasted specimens showed the best mechanical performance among the surface pre-treatments used in this work. The lap shear strength of joints with interlayer (2703 ± 114 N up to 3069 ± 166 N) was up to 55% higher than the corresponding joints without film. The fatigue life of the joints with interlayer was 4 times longer in comparison with those without interlayer; superior fatigue strength was also observed. The durability of the joints was evaluated through hydrothermal accelerated aging; the maximum reduction in initial strength was 12.4% for 28 days of aging. Finally, the failure mechanisms of the joints were discussed, demonstrating a mixture of adhesivecohesive failure mode.
A União Pontual por Fricção (FSpJ) é uma técnica internacionalmente premiada para união de estruturas híbridas metal-compósito polimérico. Esta dissertação de mestrado investigou a viabilidade técnica da produção de juntas metal-compósito com filme polimérico intermediário através do FSpJ. Juntas de alumínio 2024-T3 e laminado compósito de poli(sulfeto de fenileno) (PPS) reforçado com fibras de carbono com filme intermediário de PPS foram produzidas com sucesso. A máxima temperatura processual identificada foi de 417°C. Análises de DSC demonstraram decréscimo no grau de cristalinidade do compósito (de 22% para 12%) e acréscimo no caso do filme intermediário (de 7% para 27%) depois de submetidos ao processo de união. Análises de TGA não identificaram evidências de ocorrência de degradação termomecânica dos componentes poliméricos das juntas induzida pelo FSpJ. Os principais mecanismos de união identificados na interface das juntas foram macro- e micro-ancoramento mecânico, além de forças adesivas. As mudanças microestruturais induzidas pelo processo de união foram investigadas e correlacionadas com o desempenho mecânico local dos componentes da junta através de medidas de micro e nanodureza. Pré-tratamentos superficiais de lixamento, jateamento de areia e ativação por plasma foram realizados no componente compósito a fim de aprimorar a adesão entre os componentes a serem unidos. As superfícies pré-tratadas foram caracterizadas e suas propriedades foram correlacionadas com a resistência mecânica das juntas correspondentes. As amostras jateadas produziram juntas com a melhor resistência mecânica entre os pré-tratamentos superficiais investigados neste estudo. A resistência ao cisalhamento das juntas com filme (2703 ± 114 N até 3069 ± 166 N) apresentou-se até 55% superior à resistência das respectivas juntas sem filme. A vida em fadiga das juntas com filme apresentou-se cerca de 4 vezes mais longa em comparação às juntas sem filme. A durabilidade das juntas foi investigada através de envelhecimento hidrotérmico acelerado, sendo que a máxima redução em resistência ao cisalhamento foi de 12,4% para 28 dias de envelhecimento. Finalmente, os mecanismos de falha das juntas foram discutidos, demonstrando a predominância do modo coesivo de falha.
30
Tan, Evren. "Severe Plastic Deformation Of Age Hardenable Aluminum Alloys." Phd thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614968/index.pdf.
Full textAbstract:
Industrial products of high-strength Al-alloys are currently manufactured by thermo-mechanical processes, which are only applicable in the integrated plants requiring high investment cost. Moreover, reduction of the average grain size not less than 10 &mum and re-adjustment of process parameters for each alloy type is evaluated as disadvantage. Therefore, recently there have been many research studies for development of alternative manufacturing techniques for aluminum alloys. Research activities have shown that it is possible to improve the strength of Al-alloys remarkably by severe plastic deformation which results in ultra-fine grain size. This study aims to design and manufacture the laboratory scale set-ups for severe plastic deformation of aluminum alloys, and to characterize the severely deformed samples. The stages of the study are summarized below: First, for optimization of die design and investigation of parameters affecting the deformation finite element modeling simulations were performed. The effects of process parameters (die geometry, friction coefficient) and material properties (strain hardening, strain-rate sensitivity) were investigated. Next, Equal Channel Angular Pressing (ECAP) system that can severely deform the rod shaped samples were designed and manufactured. The variations in the microstructure and mechanical properties of 2024 Al-alloy rods deformed by ECAP were investigated. Finally, based on the experience gained, a Dissimilar Channel Angular Pressing (DCAP) system for severe plastic deformation of flat products was designed and manufactured
then, 6061 Al-alloy strips were deformed. By performing hardness and tension tests on the strips that were deformed by various passes, the capability of the DCAP set-up for production of ultra-fine grain sized high-strength aluminum flat samples were investigated.
31
Nookala, RamaKrishna. "Mechanistic Study of Silane Assisted Rubber to Brass Bonding and the Effect of Alkaline Pre Treatment of Aluminum 2024 T3 on Silane Performance." University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1148065049.
Full text
32
Radutoiu, Nicoleta. "Influence des traitements thermiques sur le comportement en corrosion à l'échelle locale de l'alliage d'aluminium en AW 2024." Phd thesis, Toulouse, INPT, 2013. http://oatao.univ-toulouse.fr/17926/1/Radutoiu_N.pdf.
Full textAbstract:
L’influence de traitements thermiques de revenu sur la corrosion localisée ainsi que sur la résistance mécanique en traction de l’alliage d’aluminium 2024 a été étudiée. Cet alliage est utilisé en construction aéronautique, à l’état T351 (mise en solution, trempe, écrouissage et maturation) grâce aux ses propriétés mécaniques élevées ; à l’état T6 (mise en solution, trempe, revenu au pic de dureté) il présente un bon compromis résistance/ductilité. Par contre, la présence d’hétérogénéités microstructurales le rend sensible à la corrosion localisée. Le traitement T7 (mise en solution, trempe, revenu après pic de dureté) peut améliorer la tenue à la corrosion au détriment des propriétés mécaniques. Dans un premier temps, il s’est agit de déterminer les conditions d’obtention des états métallurgiques T6 et T7 à étudier, à partir des courbes de dureté Vickers en fonction du temps de traitement. Les états métallurgiques obtenus, la microstructure et les propriétés mécaniques à l’échelle macroscopique et locale, ont été analysés. Un point important de cette étude a consisté en la recherche d’une méthode optimale pour la détermination de la distribution des particules intermétalliques grossières, paramètre de premier ordre pour les couplages galvaniques mis en jeu lors de la dissolution des particules. Dans un second temps, le comportement en corrosion, à différentes échelles a été suivi. Des techniques électrochimiques tel que le tracé de courbes de polarisation potentiocinétique et le suivi de potentiel libre, ont permis d’évaluer l’influence du traitement de revenu sur comportement globale en corrosion. A l’échelle locale, la dissolution des particules intermétalliques grossières a été suivie par l’évolution du potentiel de surface en fonction des différents traitements thermiques. Cela a pu être déterminé par microscopie à force atomique, couplée à l’analyse chimique des phases obtenue par spectroscopie à sélection d’énergie. Le taux de corrosion ainsi que l’abattement des propriétés mécaniques à différentes échelles, ont clairement montré l’importance du traitement T7 par rapport au traitement T6. L’ensemble des résultats présente un intérêt industriel dans la mesure où la résistance à la corrosion associée aux propriétés mécaniques peuvent indiquer la probabilité de l’endommagement du matériau.
33
Stimpfling, Thomas. "Modified layered double hydroxide (LDH) platelets as corrosion inhibitors reservoirs dispersed into coating for aluminun alloy 2024." Thesis, Clermont-Ferrand 2, 2011. http://www.theses.fr/2011CLF22169.
Full textAbstract:
L’alliage d’aluminium 2024 est très répandu dans l’industrie aéronautique et automobile. Le processus de corrosion peut entrainer des dommages irréversibles pouvant engendrer des issues fatales dans le domaine aéronautique. Ainsi plusieurs couches de revêtements sont déposées à la surface du métal à protéger pour prévenir le processus de corrosion. Depuis le début du 20ième siècle, le chrome hexavalent (CrVI) a été largement utilisé comme inhibiteur de corrosion dans les différentes couches du revêtement (prétraitement, primer et top-coat). La toxicité de ce composé envers l’homme et l’environnement a entrainé son interdiction et donc son remplacement comme agent de protection. Le confinement d’agent anticorrosif dans des nano-conteneurs a ainsi été reporté puisqu’un effet auto-réparant, en relargant sur demande, peut-être apporté : l’inhibiteur de corrosion agit quand le dommage apparait. Cette étude est focalisée sur l’utilisation de matériaux de type Hydroxydes Doubles Lamellaires (HDL) comme réservoir d’inhibiteurs de corrosion en raison leur propriété d’échange. Dans ce travail, plusieurs molécules ont été étudiées comme potentiel inhibiteur de corrosion. Celles-ci ont été tout d’abord caractérisées par DC-polarisation afin de déterminer la nature de leur comportement inhibiteur (anodique, cathodique ou les deux). Ensuite, ces agents anticorrosifs ont été intercalés dans des matrices HDL et leur capacité de relargage ainsi que leur comportement face au processus de corrosion ont été étudiés. Les particules HDL ainsi obtenues ont été dispersées dans la formulation d’un revêtement primaire et déposé directement sur l’alliage aluminium 2024. La résistance à la corrosion a été suivie par spectroscopie d’impédance complexe. Les propriétés d’auto-protection de notre revêtement (relargage d’agent anticorrosive encas de dommage) et leur propriété barrière, apportée par la morphologie lamellaire des nano-conteneurs, entrainant une diminution de la perméabilité aux espèces agressives (ex. eau, O2, électrolyte) responsable de l’apparition de cloques sur les revêtements, ont ainsi été caractériséesAluminum alloy 2024 is widely used in aircraft and automotive industry. Corrosion processes can provide irreversible damage on the metal substrate which could have a tragic issue in the aircraft domain. Thus, several coating layers have been applied on the metal substrate to prevent corrosion process. Since the beginning of the 20th century, hexavalent chromate compounds have been extensively used as corrosion inhibitor agents for paint, primer and conversion coating. The toxicity for human health and environment has led to replace such compounds. The literature has reported different possibilities to replace such unfriendly compounds. Moreover, the entrapment of corrosion inhibitors in nanocontainer provides a self-healing effect by releasing, on demand, the active species when damage occurs. This study focuses on Layered Double Hydroxide (LDH) material as reservoir due to its exchange properties. This study has characterized several potential corrosion inhibitor molecules by DC-Polarization to determine the nature of the inhibitor compound (i.e. anodic, cathodic or both of them). Further, active anticorrosive species have been intercalated into LDH framework. Then, the release of inhibitor agents and their subsequent behaviour toward corrosion inhibition have been evaluated. Modified LDH materials have been further dispersed in the primer coating formulation and applied on aluminum alloys 2024 substrate. Corrosion inhibition has been followed by electrochemical impedance spectroscopy experiments on scratched and unscratched panel which have permitted to evaluate the self-healing property of these modified LDH materials when damage occurs and the barrier property provided by the lamellar morphology of the inorganic reservoir that is found to decrease the permeation by enhancing the tortuosity of the coating layer towards aggressive species (i.e. water, O2, electrolyte) responsible of the blistering phenomenon
34
Nastic, Aleksandra. "Repair of Aluminum Alloy Aerospace Components and Cold Gas Dynamic Spray Flow Distribution Study." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32998.
Full textAbstract:
Aluminum alloys have been used for decades in aircraft as they offer a wide range of properties explicitly developed to provide a set of characteristics adapted to structural and non-structural components. However, aircraft components inevitably undergo degradation during service due to their extensive use and exposure to harsh environments. Typical repair methods are either not efficient for large scale repairs due to their low material growth rate, not suitable for field repair or involve the use of high process temperatures. The present research aims at evaluating the cold gas dynamic spray (CGDS) as a potential repair technology to restore Al7075-T6 nose landing gear steering actuator threads found on the Boeing 757 aircraft. Moreover, it studies the suitability of using cold spray to deposit Al2024 material. The influence of process parameters and substrate surface preparation on the material deposition efficiency and resulting microstructural and mechanical repair properties is also evaluated.
35
Smith, Jarrod L. "Full-Field Measurement of the Taylor-Quinney Coefficient in Tension Tests of Ti-6Al-4V, Aluminum 2024-T351, and Inconel 718 at Various Strain Rates." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1546452653747728.
Full text
36
Albannai, Abdulaziz I. Mr. "Innovative Tandem GTAW with Alternating Side-by-Side Spot-Like Welds to Minimize Centerline Solidification Cracking." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1500528823020898.
Full text
37
Young, Paul S. "Modeling and Analysis for Atmospheric Galvanic Corrosion of Fasteners in Aluminum." University of Akron / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=akron1430416832.
Full text
38
Bugarin, Aline de Fátima Santos. "Estudo da resistência à corrosão das ligas de alumínio 2024-T3 e 7475-T651 soldadas por fricção e mistura (FSW)." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-26102017-141238/.
Full textAbstract:
O processo de soldagem por fricção e mistura (FSW) tem despertado grande interesse nos últimos anos e tornou-se uma alternativa para unir materiais de baixa soldabilidade, como as ligas de alumínio das séries 2XXX e 7XXX, as quais são empregadas na estrutura das aeronaves, por possuírem elevada relação resistência/peso. O processo FSW, todavia, causa mudanças microestruturais nos materiais soldados, particularmente na zona misturada (ZM) e nas zonas termicamente (ZTA) ou termomecanicamente (ZTMA) afetadas. Estas mudanças geralmente interferem no desempenho frente à corrosão das ligas soldadas. No presente estudo, a resistência à corrosão das ligas de alumínio 2024-T3 e 7475-T761, unidas pelo processo FSW foi investigada em solução 10 mM de NaCl. Ensaios de visualização em gel ágar-ágar e de imersão associados a técnicas microscópicas foram realizados para investigar o efeito do acoplamento galvânico na corrosão das diferentes regiões da junta soldada. Os resultados do ensaio de visualização em gel mostraram que, quando acopladas, a liga 2024 atua como cátodo e a 7475 como ânodo. Os ensaios de imersão revelaram acoplamento galvânico entre as ligas na zona misturada (ZM). A região mais afetada pela corrosão foi a ZTMA da liga 7475, com corrosão intergranular desde as primeiras horas de imersão. A influência do processo de soldagem na resistência à corrosão das duas ligas de alumínio foi investigada por ensaios eletroquímicos. Os ensaios eletroquímicos adotados foram medidas de potencial de circuito aberto (PCA) em função do tempo de exposição ao meio corrosivo, espectroscopia de impedância eletroquímica (EIE) e curvas de polarização potenciodinâmica. Os ensaios de polarização mostraram elevada atividade eletroquímica na zona de mistura indicada pelos altos valores de densidade de corrente em comparação com as demais zonas testadas. Os resultados de EIE globais mostraram que nas primeiras horas de exposição ao eletrólito o processo de corrosão foi predominantemente controlado pela liga 7475; todavia, com o tempo de exposição ao eletrólito, a corrosão passou a ser controlada pela liga 2024.Friction stir welding (FSW) has roused great interest in recent years and it is now an alternative for joining materials of low weldability, such as the aluminum alloys of the 2XXX and 7XXX series, used in the aircrafts structure due to their high strength /weight ratio. However, FSW causes material microstructural changes, mainly in the stir zone (SZ), the heat affected zone (HAZ) or thermomechanically (TMAZ) affected zones of the materials welded. These generally interfere with the corrosive performance of the welded joint. In the present study, the corrosion resistance of the 2024-T3 and 7475-T761aluminum alloys, joined by FSW was investigated in 10 mM NaCl electrolyte. Agar-agar gel and immersion tests associated with microscopic techniques were performed to investigate the effect of galvanic coupling between the welded materials. Results from this test showed that, when galvanically coupled, the 2024 alloy acts as cathode and the 7475 as anode. Immersion tests revealed galvanic coupling between the alloys in the SZ. The zone most susceptible to corrosion was the TMAZ of the 7475. Intergranular corrosion was observed in this zone since the first hours of immersion. The influence of the welding process on the corrosion resistance of the alloys was also evaluated by electrochemical tests. The electrochemical tests adopted were open circuit potential measurements (OCP) as a function of time of exposure to the electrolyte, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curves. The polarization tests showed high electrochemical activity in the stir zone indicated by the high current densities measured comparatively to the other tested zones. The global EIS results indicated that in the first few hours of exposure to the electrolyte the corrosion process was predominantly controlled by the 7475 alloy; however, with time of exposure to the electrolyte, the corrosion was controlled by alloy 2024.
39
Le, Thi My Linh. "Simulation de l'effet du confinement sur l'endommagement d'un assemblage en alliage d'aluminium." Thesis, Dijon, 2013. http://www.theses.fr/2013DIJOS048.
Full textAbstract:
Pour les structures aéronautiques, les zones sensibles à la corrosion sont principalement celles où le plan de protection de la structure peut être mis en défaut, comme à l’intérieur des joints de recouvrement (dénommé «lap joint» en anglais). Les assemblages de tôles métalliques réalisés par recouvrement en utilisant, par exemple le rivetage, peuvent présenter des défauts de contact et donc il peut exister un interstice entre les deux parties de l’assemblage. En général cet interstice est isolé de l’environnement extérieur par un mastic. Mais il y a un risque de piégeage d’humidité plus ou moins concentrée en ions agressifs qui peut provoquer des endommagements ou aggraver ceux initiés sur des défauts des revêtements. Le premier objectif de cette thèse est de développer une méthodologie permettant de reproduire, de manière contrôlée et de façon la plus représentative de cas réels, la corrosion d’un alliage d’aluminium 2024-T3 constituant un joint de recouvrement afin d’effectuer des observations complétées par des mesures chimiques et électrochimiques. Le deuxième objectif est de tester l’application de modèles de transport réactif (en milieu confiné) pour voir s’il est possible de simuler les réponses (chimiques ou électrochimiques) mesurées expérimentalement et donc de prédire sur le long terme l’évolution d’un assemblageFor aircraft structures, corrosion sensitive areas are mainly those where the protection of the structure may suffer local breakdowns, as encountered inside lap joints. The assemblies of metal plates by overlapping (riveting) may present some defects in contact and consequently a gap can exist between the two parts of the assembly. Typically this gap is isolated from the outside environment by a sealant. But there is a risk of trapping of moisture more or less concentrated in aggressive ions which can induce corrosion or increase the damages initiated on coating defects. The first objective of this thesis is to develop a methodology to reproduce in a controlled manner and in the most representative way regarding actual cases, the corrosion of a lap joint made of aluminum alloy 2024- T3 plates, to perform not only observations but also chemical and electrochemical measurements. The second objective is to test the application of reactive transport models (in confined media) to check if it is possible to simulate the chemical or electrochemical changes recorded during experiments and thus to predict the long-term evolution of lap-joint in humid environment
40
Růžička, Martin. "Závislost mezi pevností v tahu a tvrdostí hliníkových slitin." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-417516.
Full textAbstract:
This thesis deals with relationship between tensile strength and hardness of aluminium alloys. The introduction provides an overview of aluminum aloys and their properties. In the following section there is an analysis of the processing of aluminum alloys. A large part is devoted to the course of precipitation hardening. The second part of the thesis contains a practical part, which describes the methodology of measuring hardness and tensile strength. The measurement process is described below. At the end, the measured data are processed into various graphs and their results are evaluated.
41
Pearl, David Lee. "A Novel Characterization of Friction Stir Welds Created Using Active Temperature Control." Miami University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=miami1618585976565749.
Full text
42
Even, Anaïs. "Compréhension des mécanismes d'inhibition de la corrosion dans le cadre de revêtements hybrides pour pièces aéronautiques." Thesis, Lorient, 2019. http://www.theses.fr/2019LORIS534.
Full textAbstract:
La lutte contre la corrosion dans l'industrie aéronautique est un défi permanent. Pour y répondre, le système actuel fait appel aux chromates qui présentent des qualités anticorrosives. Ces composés sont cependant classés cancérigènes, mutagènes, reprotoxiques. Un revêtement hybride sol-gel/polymère non toxique a été développé pour proposer une alternative au système de référence. Il présente des performances de protection contre la corrosion de l’alliage d’aluminium 2024-T3. Ce revêtement est innovant par son application par pulvérisation et sa polymérisation sous irradiation UV. Ce système est complexe et la compréhension des mécanismes mis en jeu lors de l’inhibition de la corrosion a fait l’objet de ce travail de thèse. Tout d'abord, les travaux menés ont permis de mettre en évidence la protection passive du revêtement et de relier ses performances à la structuration du film jusqu’à l’échelle nanométrique. Ensuite, en cas d’endommagement du revêtement, la protection active du revêtement a été étudiée. Lors de la sollicitation du revêtement, la réponse active du système inhibiteur de corrosion a été caractérisée par une exposition en milieu naturel et complétée par des essais accélérés de corrosion cyclique. Ce travail de recherche a montré que l’action d’un inhibiteur de corrosion est étroitement dépendante de la matrice dans laquelle il est intégré. La matrice du revêtement étudié est fermée et dense, conférant un effet barrière, mais réduisant la mobilité des espèces actives lorsque le substrat à protéger est mis à nu. Ces tests révèlent que le revêtement hybride apporte uneprotection supérieure par comparaison à une peinture commerciale non chromatéThe struggle against corrosion in the aeronautical industry is an ongoing challenge. To meet these requirements, the current system uses chromates with anticorrosive properties. However, these compounds are classified as carcinogenic, mutagenic, reprotoxic. A non-toxic sol-gel/polymer hybrid coating has been developed to provide an alternative to the reference system. This coating is innovative in its application by spray and a one-step UV-curing polymerization. This system is complex and the understanding of the mechanisms involved in corrosion inhibition has been the subject of this thesis work. First, work conducted has allowed to highlight the passive protection of the coating and link its performance to the film structuration down to the nanoscale. Then, in case of damage to the coating, the active protection of the coating was studied. During solicitation of the coating, the active response of the corrosion inhibitor system was characterized by exposure to natural environment, supplemented by accelerated cyclic corrosion tests. This research work has shown that the action of a corrosion inhibitor is closely dependent on the matrix in which it is integrated. The coating matrix is closed and dense, providing a barrier effect, but reducing the mobility of active species when the substrate to be protected is exposed. These tests have shown that the hybrid coating provides superior protection in comparison with a non-chromatedcommercial paint
43
Harper, Christopher Paul. "Effect of alumina particle additions on the aging kinetics of 2014-aluminum matrix composites." Thesis, Monterey, California. Naval Postgraduate School, 1991. http://hdl.handle.net/10945/26510.
Full textAbstract:
Differential Scanning Calorimetry (DSC) was conducted on 2014 aluminum, 2014 aluminum reinforced with 10 and 15 percent by volume of alumina particles, 2024 aluminum, and a A1/4%Cu alloy. Electrical resistivity and matrix micro-hardness measurements were conducted on the 2014 aluminum alloy and the metal matrix composites (MMC) during isothermal aging. Transmission Electron Microscopy (TEM) and DSC were used to identify the metastable phases formed in the 2014 aluminum alloy. The effect of alumina particle addition on the precipitation, growth and thermal stability of the metastability phases in the 2014 aluminum alloy and MMC were studied. Results were used to characterize the effect of the alumina reinforcement on the aging kinetics of the 2014 aluminum alloy matrix
44
Subramaniyan, Jaya. "Extrusion of 2024 aluminium alloy sections." Thesis, Imperial College London, 1989. http://hdl.handle.net/10044/1/47677.
Full text
45
Ganguly, Supriyo. "Non-destructive measurement of residual stresses in welded aluminium 2024 airframe alloy." Thesis, n.p, 2004. http://ethos.bl.uk/.
Full text
46
Gates, Nicholas R. "Fatigue Behavior under Multiaxial Stress States Including Notch Effects and Variable Amplitude Loading." University of Toledo / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1469637495.
Full text
47
Peng, Ying. "Synthesis, structures and reactions of aluminum(I) and aluminum(III) compounds." Doctoral thesis, [S.l. : s.n.], 2004. http://webdoc.sub.gwdg.de/diss/2004/peng/peng.pdf.
Full text
48
Guillaumin, Valérie. "Étude comparative de la sensibilité à la corrosion localisée des alliages d'aluminium 2024 et 6056." Toulouse, INPT, 1998. http://www.theses.fr/1998INPT022C.
Full textAbstract:
La sensibilite des alliages d'aluminium 2024 et 6056 vis-a-vis de la corrosion localisee et plus particulierement de la corrosion intergranulaire a ete etudiee en milieu chlorure. La courbe de polarisation potentiocinetique de l'alliage 2024 t351 presente 2 potentiels de rupture. Le plus actif, vers 720 mv, correspond au potentiel de dissolution de la phase riche en cu et mg. Pour des potentiels superieurs a 720 mv, les particules intermetalliques grossieres riches en cu et mg sont severement attaquees : dissolution selective de l'al et du mg et fort enrichissement en cu. Le plus noble, vers 620 mv, correspond au potentiel de rupture de la matrice. Le mecanisme de la corrosion intergranulaire consiste en la dissolution selective d'une zone appauvrie en cu situee le long des joints de grains et en la dissolution des precipites intergranulaires riches en cu et mg. La courbe de polarisation potentiocinetique de l'alliage 6056 presente un seul potentiel de rupture : le potentiel de rupture de la matrice. Les particules grossieres riches en mg et si servent de sites d'initiation pour les piqures. Les piqures servent de sites d'initiation pour la corrosion intergranulaire qui prend naissance sur les parois des piqures. Il y a dependance entre les deux types de corrosion. Le mecanisme de corrosion intergranulaire de l'alliage 6056 consiste en la dissolution preferentielle d'une zone appauvrie en cu et si, situee le long des joints de grains, tandis que les precipites intergranulaires riches en si et cu jouent le role de cathodes locales. Le traitement thermique de sur-revenu t78 ameliore la tenue a la corrosion intergranulaire de l'alliage 6056. Un classement des alliages en fonction de leur resistance croissante a la corrosion intergranulaire assistee par la contrainte a pu etre etabli : 2024 t351 < 6056 t6 < 6056 t78 des immersions d'echantillons dans une solution exco ont montre que l'alliage 6056 est plus resistant a la corrosion feuilletante que l'alliage 2024.
49
Elabar, Dawod. "Effect of sulphate impurity in chromic acid anodizing of aluminium and aluminium alloy." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/effect-of-sulphate-impurity-in-chromic-acid-anodizing-of-aluminium-and-aluminium-alloy(ec562f6a-6bc9-4bb4-9eee-468d539f90a2).html.
Full textAbstract:
In this work, the nucleation and growth of pores in anodic films formed on aluminium in chromic acid and the effect of low levels of sulphate impurity in the anodizing bath on the formation of the films on aluminium and AA 2024 alloy are investigated. The sulphate concentrations considered include levels within specified limits for industrial processing. The anodizing is carried out either potentiostatically or by stepping the voltage. The films are examined by scanning electron microscopy, transmission electron microscopy and atomic force microscopy to determine the pore spacing, pore population densities, pore diameters and film thicknesses. Film compositions were determined using energy-dispersive X-ray spectroscopy, Rutherford backscattered microscopy and nuclear reaction analysis. In order to investigate the mechanism of pore formation, two tracer methods are employed. In one method, anodic films are formed first in an arsenate electrolyte in the second method, a tungsten tracer band deposited by magnetron sputtering. The behaviours of arsenic and the tungsten are investigated during the subsequent anodizing in chromic acid. The results suggest that the initiation and growth of pores in occurred as a result of electric field assisted chemical dissolution. The effect of sulphate impurity in the chromic acid is investigated using electrolytes with different sulphate content. In the initial stages of anodizing aluminium at 100 V, sulphate impurity at a level of 38 ppm in the chromic acid is shown to lead to significant incorporation of sulphate ions into the anodic film, a lower current density, a smaller cell size and less feathering of the pore walls. In addition, the efficiency of film formation is increased. In later stages of anodizing, the growth of larger pores and cells, leads to a duplex film morphology, with finer pores in the outer region. The change in pore size correlates with a reduction in the incorporation of sulphate into the film. From the results of sequential anodizing experiments, it is suggested that incorporated sulphate ions generate a space charge layer, which has an important role in determining the current density. The effects of higher sulphate concentrations up to 3000 ppm are investigated, which are shown to significantly affect the current density and the pore diameter. Anodizing of aluminium and AA 2024 alloy was also carried out according to industrial practice. The results show that there is significant effect of sulphur impurity on the film thickness. Corrosion tests in 3.5 % NaCl solution for the alloy after anodizing in low (smaller or equal to 1.5 ppm) and high (~38 ppm) sulphate-containing chromic acid electrolytes demonstrate a better corrosion resistance with films formed in the latter electrolyte.
50
Efthymiadis, Panos. "Multiscale experimentation & modeling of fatigue crack development in aluminium alloy 2024." Thesis, University of Sheffield, 2015. http://etheses.whiterose.ac.uk/7735/.
Full textAbstract:
The objective of this research project is to be able to understand the role of various microstructural features on Fatigue Crack Initiation (FCI) of metallic alloys. By employing a novel experimental set-up, mechanical testing was performed in situ within an SEM chamber, and the deformation of the individual grains was observed real time. A physically-based Crystal Plasticity (CP) model was then developed that accurately predicts the macro and micro mechanical behaviour for Al2024 T3. An experimentally informed FCI criterion was developed that accounts for the effect of local slip bands and the applied local strains. While ‘precious’ insights were given on the small crack growth regime observing the occurring microscale phenomena. FCI is a multiscale process and thus evaluating the microscale does not cover fully the understanding of local deformation and damage. Thus a multiscale DIC process was employed to better understand the macro and mesoscale as well. 3D Digital Image Correlation (DIC) was employed and the strain distributions (at the sample scale) were obtained for various loading conditions. High magnification camera based 2D DIC was then used and the strain measurements were also extracted at clusters of grains. Useful observations were given for the different strain components (εxx, εyy, εxy). Finally the total fatigue lifetime of the component was compared to the modeled FCI for various loading conditions.