Dissertationen zum Thema „Zr-Cu“
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Carrasco, Valenzuela Wilson Rodrigo. „Cristalización de Aleaciones Amorfas Cu – Zr – Al“. Tesis, Universidad de Chile, 2009. http://www.repositorio.uchile.cl/handle/2250/103378.
Der volle Inhalt der QuelleXu, Min. „Crystallization of Zr₂Pd(subscript x)Cu(₁₋(subscript x)) and Zr₂Ni(subscript x)Cu(₁₋(subscript x)) metallic glass“. [Ames, Iowa : Iowa State University], 2008.
Den vollen Inhalt der Quelle findenАбдулов, А. Р. „Термодинамические свойства расплавов Cu-Ti-Zr, Cu-Ni-Ti, Cu-Fe-Ti и моделирование их склонности к аморфизации“. Diss. des Kandidaten der chemischen Wissenschaften, Донбасская государственная машиностроительная академия, 2008.
Den vollen Inhalt der Quelle findenIsmail, Nahla. „Electrochemical Hydrogen Absorption by Zr-Cu-Al-Ni Metallic Glasses“. Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2002. http://nbn-resolving.de/urn:nbn:de:swb:14-1037185293084-48289.
Der volle Inhalt der QuelleCasas, Gómez Camilo Andrés. „Simulación Dinámica Molecular de Aleaciones Amorfas de Cu-Zr-Al“. Tesis, Universidad de Chile, 2010. http://www.repositorio.uchile.cl/handle/2250/102475.
Der volle Inhalt der QuelleKosiba, Konrad. „Flash-Annealing of Cu-Zr-Al-based Bulk Metallic Glasses“. Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-222874.
Der volle Inhalt der QuelleNekouie, Vahid. „Deformation behaviour of a Zr-Cu-based bulk metallic glass“. Thesis, Loughborough University, 2017. https://dspace.lboro.ac.uk/2134/25246.
Der volle Inhalt der QuelleFrigerio, Jean-Marc. „Densités d'états électroniques d'alliages métalliques amorphes Cu-y, Cu-Zr déterminées par spectroscopie optique et d'électrons“. Paris 6, 1986. http://www.theses.fr/1986PA066184.
Der volle Inhalt der QuelleMaria, Felipe Henrique Santa. „Análise térmica da influência do oxigênio na amorfização de ligas baseadas em Cu-Zr“. Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/18/18158/tde-23052018-105250/.
Der volle Inhalt der QuelleCu-Zr-based bulk metallic glasses represent a very promising class of structural materials with interesting properties resulting from the amorphous nature. It is known that oxygen has a great influence on the formation of the amorphous structure and consequently on the properties of these materials. In the present work, Cu-Zr-based amorphous alloys were thermally analyzed in order to observe their behavior against oxygen contamination. Thermal analyzis were performed on a differential scanning calorimetry (DSC) equipment, and characteristic temperatures as glass transition, crystallization, melting and liquidus were determined. It was concluded that, according to the literature, the crystallization process is favored by the presence of oxygen, causing a decrease in the activation energy of the crystallization processes of the worked alloys. Through tests that simulated heat treatments, the amorphous samples were crystallized in order to form composites between crystals and metallic glasses in order to reduce the brittleness of the alloys.
Pauly, Simon. „Phase formation and mechanical properties of metastable Cu-Zr-based alloys“. Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-39545.
Der volle Inhalt der QuelleKhorashadizadeh, Anahita [Verfasser]. „Microstructure characterization of ultra-fine grained Cu-0.17wt%Zr / Anahita Khorashadizadeh“. Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2012. http://d-nb.info/1029489432/34.
Der volle Inhalt der QuelleAleman, Omar Jimenez. „Deposition and characterization of magnetron sputtered coatings in the Zr-Cu-JN and Zr-li-JN(B) ternary systems“. Thesis, University of Sheffield, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.521963.
Der volle Inhalt der QuelleAsgharzadeh, Javid Fatemeh. „Phase formation, martensitic transformation and mechanical properties of Cu-Zr-based alloys“. Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-210276.
Der volle Inhalt der QuelleThe fact that the presence of Co extends the stability range of B2 CuZr to room temperature, together with the significant effect of Al on improving the glass forming ability of the CuZr system was the motivation to investigate the ternary and quaternary CuZr alloys with the aim of synthesizing BMG composites containing B2 (Cu,Co)Zr crystals. This PhD thesis deals with preparation and characterization of Cu50-xCoxZr50 (0 ≤ x ≤ 20) and Cu50-xCoxZr45Al5 (x = 2, 5, 10 and 20) alloys. The phase formation, thermal stability, microstructure, martensitic transformation and mechanical properties of these alloys were investigated. The dependence of phase formation on solidification rate and the thermodynamically stability of Cu-Co-Zr alloys reveals that the addition of Co decreases the glass forming ability (GFA) of the Cu-Co-Zr alloys and changes the stable crystalline products of the system from Cu10Zr7 + CuZr2 to (Cu,Co)Zr phase with a B2 structure. The results indicate that for the melt-spun ribbons with at least 5 % Co, the glass crystallizes directly into B2 (Cu,Co)Zr, while in the case of bulk specimens, compositions with 0 ≤ x < 5 of Co contain the monoclinic (Cu,Co)Zr phase and Cu10Zr7 and CuZr2, whereas, for x ≥ 10, the B2 (Cu,Co)Zr phase is the equilibrium phase at room temperature. Furthermore, increasing the cobalt content decreases the martensitic transformation temperatures to lower temperatures. The phase formation in the ternary system is summarized in a pseudo-binary (Cu,Co)Zr phase diagram, that helps for designing new shape memory alloys, as well as bulk metallic glass composites with the addition of glass former elements. In the quaternary alloys, Al increases the glass transition and crystallization temperatures and hence improves the GFA of the system. The X-ray analysis illustrates that for the melt-spun ribbons, the crystallization products vary from Cu10Zr7 + CuZr2 + AlCu2Zr to (Cu,Co)Zr + AlCu2Zr when Co ≤ 5 and Co ≥ 10, respectively. Depending on the cooling rates, the bulk samples represent a fully amorphous structure or BMG composites or a fully crystalline structure. For Co ≤ 5, beside (Cu,Co)Zr and AlCu2Zr, Cu10Zr7 exists as well. Scanning (SEM) and transmission (TEM) electron microscopy investigations were done to investigate the effect of Al and Co addition to the microstructure of CuZr alloys. In the case of Cu-Co-Zr-Al alloys, Cu30Co20Zr45Al5 (ɸ = 4 mm) and Cu45Co5Zr45Al5 (ɸ = 2 mm) compositions were selected for the microstructure verification using TEM. Later, the heterogeneity of the microstructure in Cu40Co10Zr45Al5 (ɸ = 2 mm) alloy was considered. The effect of Co on the mechanical properties of rapidly solidified Cu50-xCoxZr50 (x = 2, 5, 10 and 20 at.%) alloys depict that the deformation behavior of the rods under compressive loading strongly depends on the microstructure, and as a results, on the alloy composition. Cobalt affects the fracture strength of the as-cast samples; and deformation is accompanied with two yield stresses for high Co-content alloys, which undergo deformation-induced martensitic transformation. Instead samples with a martensitic structure show a work-hardening behavior. For quaternary alloys, the effects of cooling rate and chemical composition on mechanical properties of the alloys were investigated. Cu48Co2Zr45Al5 (ɸ= 1.5, 2, 3 and 4 mm) and Cu45Co5Zr45Al5 (ɸ = 3 mm) compositions were selected to discuss the effect of cooling rate and heterogeneity, respectively. The results depict that the mechanical properties of Cu50-xCoxZr45Al5 alloys strongly depend on the microstructure and the volume fraction of the amorphous and crystalline phases. The deformation-induced martensitic transformation of Cu40Co10Zr50 and Cu40Co10Zr45Al5 as-cast rods, was studied by means of high-energy X-rays. The in situ compression measurements were performed in track control and load control modes. The macroscopic and microscopic stress-strain behavior, as well as the phase transformation kinetics were considered. The relative changes in the fully integrated intensity of the selected B2 and martensite peaks, which indicate the changes in volume fraction of the corresponding phases under deformation, was described as phase transformation volume, M/M+B2
Fernández, Urrutia Rubén Marcos. „Recubrimientos de Cu-Zr-Al Amorfos Producidos Mediante Técnicas de Aspersión Dinámica“. Tesis, Universidad de Chile, 2010. http://www.repositorio.uchile.cl/handle/2250/102309.
Der volle Inhalt der QuelleHendrichs-Troeglen, Nicolas Jorge. „Consolidation structures and properties of rapidly soldified Cu-Cr-Zr alloy powders“. Thesis, University of Sheffield, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319440.
Der volle Inhalt der QuelleGomiero, Philippe. „Microstructure et propriétés mécaniques de l'alliage Al-Li-Cu-Mg(Zr) (2091)“. Grenoble INPG, 1990. http://www.theses.fr/1990INPG0129.
Der volle Inhalt der QuelleDéo, Leonardo Pratavieira. „Verificação da precisão de um critério para a seleção de composições formadoras de vidro em ligas metálicas do ternário Zr-Ni-Cu“. Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/88/88131/tde-14122011-142544/.
Der volle Inhalt der QuelleIn the present work it was verified the accuracy of a proposed criterion to predict compositions of glassy alloys applied in the Zr-Ni-Cu system. This criterion combines the topological instability parameter (\'lâmbda\') and a thermodynamic parameter (\'delta\' h) among the alloying elements. The two parameters correlate quantitatively the chemical composition with the glass forming ability. This criterion is a promising and simple tool to guide and reduce the tedious and intensive work of finding good compositions of glasses in metallic systems. In an attempt to prove the efficiency of such tool, the methodology was to calculate the parameter for the system of interest and prepare alloys in accordance with the compositions provided by the tool. The methodology of preparation of the alloys followed the electric arc- melting and subsequent use of fast cooling techniques, melt-spinning and splat-cooling for the production of metallic ribbons and discs, respectively, and a wedge-shaped chiller mold to produce bulk metallic samples. For samples prepared from the melt-spinning and splat-cooling, it was verified the accuracy of the selection criteria by quantifying the percentage of glassy phases from X-ray diffractograms and their thermal behaviors from thermograms produced by differential scanning calorimetry (DSC). For alloys produced from the wedge-shaped mold, some results were obtained with evidence of vitreous structures that were characterized by X-ray diffraction and metallography. Therefore the conclusion is that the selection criteria applied to the system Zr-Ni-Cu can be used to develop favorable compositions for the formation of glasses before the production of the alloys. It is concluded that the selection criterion is a good tool and can be used as a guide to find the best glass forming alloys, thus reducing the experimental procedures of trial and error.
Poblano-Salas, Carlos A. „The microstructure and properties of consolidated water atomised Cu-Cr-Zr alloy powders“. Thesis, University of Sheffield, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.425174.
Der volle Inhalt der QuelleBerezina, A. L., N. N. Budarina, A. V. Kotko, O. A. Molebny, A. A. Chayka und A. Y. Ischenko. „Structural changes in friction-stir welded Al-Li-Cu-Sc-Zr (1460) alloy“. Thesis, Sumy State University, 2011. http://essuir.sumdu.edu.ua/handle/123456789/20580.
Der volle Inhalt der QuelleMAIS, LAURA. „Electrodeposition of Nb, Ta, Zr and Cu from Ionic Liquid for Nanocomposites Preparation“. Doctoral thesis, Università degli Studi di Cagliari, 2015. http://hdl.handle.net/11584/266571.
Der volle Inhalt der QuelleGaganov, Alexander. „Hochfeste und hochleitfähige Cu-Ag-Leitermaterialien“. Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-62066.
Der volle Inhalt der QuelleLaffont, Paul. „Comportement à la rayure de verres métalliques massifs base CuZr“. Electronic Thesis or Diss., Université Grenoble Alpes, 2024. http://www.theses.fr/2024GRALI018.
Der volle Inhalt der QuelleMetallic glasses (MGs) exhibit incredible mechanical properties arising from their particular amorphous structure. This structure is also responsible for the specific deformation mechanisms of MG leading to the nucleation and propagation of shear bands (SBs). Nevertheless, under complex loading, the deformation mechanisms remain to be understood, for example, it isnearly impossible to predict the wear behaviour and so, the lifetime which isdirectly linked to the wear loss of a metallic glass sample. This work aims to understand the mechanical behaviour of MGs, in light of their specific deformation mechanisms, under scratch test for three differents Zr- and Cu-based MGs.The analogy of indentation and scratch tests revealed the importance of the shear strength for MGs. Indeed, the introduction of a lateral force in the case of a scratch test induces the creation of SBs ahead of the tip of the indenter. The activation of the softening mechanism has also been pointed out, which leads to the sink in of the indenter during a scratch test. The study of thermally treated MGs (relaxed and partially crystalized) helps us revealing the impact of the hardness along with the fracture toughness on the wear resitance of a MG. Thereby, the MG showing the best wear resistance is not necessarily the hardest MG, as admitted by the scientific community. Eventually, different strategies in agreements with the results shown in this work, are discussed in order to minimize the wear during the scratch of a MG
Bicker, Matthias. „Strukturelle Änderungen in dünnen amorphen Zr-Al-Ni-Cu- und Ta-Si-N-Schichten“. [S.l. : s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=960137440.
Der volle Inhalt der QuelleSun, Kou María del Rosario, und Sagrario Mendioroz. „Preparación y propiedades de montmorillonitas pilaradas con Zr y su interacción con Cu(II)“. Revista de Química, 2013. http://repositorio.pucp.edu.pe/index/handle/123456789/100753.
Der volle Inhalt der QuelleCataldo, Laurent. „Contribution à l'élaboration et à l'optimisation d'alliages magnétiques permanents Sm-Co-Cu-Fe-Zr“. Lyon 1, 1996. http://www.theses.fr/1996LYO10206.
Der volle Inhalt der QuelleRahioui, Ahmed. „Contribution à l’Étude microstructurale des effets d'implantation d’espèces métalliques (Cu,Zr,Fe) dans l'alumine“. Lyon, INSA, 1993. http://www.theses.fr/1993ISAL0046.
Der volle Inhalt der QuelleIon implantation is being investigated as a method to alter near-surface properties of materials, particularly ceramics. It allows, in non-equilibrium conditions, a thin layer to be created, the composition and structure have beneficial effects of surface properties. This study was related to the high doses implantation of metallic ions into polycrystalline alumina. The species (Cu, Zr, Fe) has been chosen from the gap between their valences and the formation free enthalpies of their oxides. In order to understand the microstructural evolution of the as-imp- planted and the implanted-annealed samples, various techniques have been used, suer as transmission electron microscopies (conventional and high resolution), X-ray emission spectroscopy (EDS) and X-ray absorption spectroscopy (XANES) The observed microstructure in the as-implanted material is composed of several regions. The first of these consists in of highly divided alumina grains including a fine precipitation of the metallic species. In the case of iron, the spinel phase is also observed near the implanted surface. Beyond the implanted zone, a high density M crystalline defects is seen in the alumina lattice. Moreover, an amorphous-like layer is produced by implantation of zirconium. In most cases, the evolution of the implanted zone composition after annealing is consistent with the expected equilibrium phase diagrams
Mechler, Stefan. „Die Rolle der ikosaedrischen Nahordnung bei Glasbildung und Kristallisation im System Zr-Ti-Ni-Cu-Be“. [S.l.] : [s.n.], 2007. http://opus.kobv.de/tuberlin/volltexte/2007/1539.
Der volle Inhalt der QuellePavlenyi, Marc. „Effects of short range order on structural and transport properties of Cu-Ni-Zr amorphous alloys“. Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59379.
Der volle Inhalt der QuelleIt is observed that there is a linear increase in the values of the susceptibility, resistivity, and superconducting transition temperature of the system from CuZr$ sb2$ to NiZr$ sb2.$ This is attributed to an increase of the electronic density of states as the concentration of Ni increases. There is little or no influence on transport properties due to topological short range order.
Davin, Laury F. „Ultra-fine characterisation of nanostructures in Al-(Li)-Cu-Mg-(Zr) alloys by three-dimensional atom probe“. Thesis, University of Oxford, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.408822.
Der volle Inhalt der QuelleVerdu, Catherine. „Origines microstructurales et modélisation de l’Amorçage des fissures inter granulaires d'un alliage Al-Li-Cu-Mg-(Zr)“. Lyon, INSA, 1991. http://www.theses.fr/1991ISAL0012.
Der volle Inhalt der QuelleThis work is concerned with the microscopic mechanisms of inter granular fracture in an Al. Li. Cu. Mg. (Zr) alloy. By means of an original approach, it has been shown that the fracture of this alloy is due to his specific plastic deformation mode. Indeed, only a one single slip system is mainly activated due to a very pronounced crystallographic texture and the shearing of Al Li precipitates. Therefore incompatible deformation occurs between contiguous grains. It induces a localisation of the plastic deformation near the grain boundaries and the initiation of a very coarsened and sinuous slip. Inter granular granular cracks are mainly due to the interaction of slips with grain boundaries. The crack initiation is also enhanced because of the plastically interaction stress field induced by incompatibility problems between: the T2 phase and the precipitate free zone. In the last part of this work an inter granular crack initiation model is proposed from the formation of dislocations pile ups against the grain boundaries. This model leads to à clear understanding of the inter granular fracture in the againg Al. Li. Cu. Mg. (Zr) alloys
Bolam, Vivienne Jane. „The influence of surface treatments on the fatigue properties of an AL-LI-CU-MG-ZR (8090) alloy“. Thesis, University of Southampton, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315087.
Der volle Inhalt der QuelleXiaofeng, Gu. „Preparation, glass forming ability, crystallization and deformation of (Zr, HF)-CU-NI-AL-TI based bulk metallic glasses“. Available to US Hopkins community, 2003. http://wwwlib.umi.com/dissertations/dlnow/3080671.
Der volle Inhalt der QuelleRitter, Yvonne [Verfasser], Karsten [Akademischer Betreuer] Albe und Gerhard [Akademischer Betreuer] Wilde. „Molecular Dynamics Simulations of Structure-Property Relationships in Cu-Zr Metallic Glasses / Yvonne Ritter. Betreuer: Karsten Albe ; Gerhard Wilde“. Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2012. http://d-nb.info/1106256514/34.
Der volle Inhalt der QuelleMarques, Paulo Wilmar Barbosa. „Relaxação estrutural em ligas vítreas e parcialmente cristalizadas do sistema Cu-Zr-Al através da técnica de espectroscopia mecânica“. Universidade Federal de São Carlos, 2013. https://repositorio.ufscar.br/handle/ufscar/4965.
Der volle Inhalt der QuelleUniversidade Federal de Sao Carlos
In recent years the study of bulk metallic glasses (BMG) is being of great scientific and technological interest due to their unique properties (the lack of long range atomic order in the structure and compositional homogeneity similar to the liquid state). These alloys show better mechanical properties, superior corrosion resistance, high yield stress and fracture toughness, if compared to their crystalline counterparts. However, a physical understanding of disordered structure and how it affects the properties of metallic glasses is still considered one of the great challenges in Condensed Matter Physics and Materials Science. Since the Mechanical Spectroscopy technique is sensitive to phase transitions and dynamical processes, it provides the anelastic spectra (internal friction and oscillation frequency) as function of temperature, through which relevant informations to the understanding of structural and vibrational changes of metallic glasses are obtained. In this study, the mechanical spectroscopy technique was used to investigate dynamic processes related to elastic and electronic contributions of atomic motions and clusters, as well as other changes in the atomic bonds on the glassy and partially crystallized alloys of the ternary system Cu-Zr-Al. The samples were obtained combining criteria of the minimum topological instability and the average electronegativity (λmin∙Δē), and were investigated at temperatures above and below room temperature (300 K) with applied frequencies in Hz, kHz and MHz magnitude order. Above room temperature, the application of alternated stresses in the order of Hz and KHz allowed us to observe structural changes involving atomic rearrangements due to anelastic, viscoelastic and thermoelastic aspects present in the relaxation process. In this temperature range, the viscoelastic and thermoelastic character overlaps the anelastic relaxation mechanisms that could be observed in metallic glasses. Analysis of samples with nominal composition Cu54Zr40Al6 - nanocrystalline and vitreous - show that the anelastic relaxation processes begin below room temperature, and are dependent of the applied frequency. When the applied frequencies are in the Hz magnitude order, some clusters have their shell affected by the alternate elastic stresses. When the samples are excited with kHz order of magnitude frequencies, two well-defined relaxation centers will appear. This phenomenon is caused by the movement of clusters which are created and annihilated at the same time the stress is applied. When the applied stresses are of MHz magnitude order, the clusters are rearranged in a more efficient way, in which the less stable clusters involving Zr are annihilated and clusters with Al or Cu at their centers are reordered in order to promote the stability of the icosahedral structure embedded in the amorphous matrix. Under applied mechanical energy corresponding to the MHz frequencies, more stable structures are created and the clusters approach, interact and interpenetrate each other, giving rise to the free bond planes where the superclusters rearrange leading to the formation of medium range chains. Under persistent mechanical stimulation in MHz, the structures begin to form long-range order that lead to formation of the first crystalline precipitates. Those purely anelastic relaxation mechanisms are initiated at low temperatures, and in most cases, it´s not possible to observe them at higher temperatures due to the viscoelastic and thermoelastic character, which generally occur simultaneously in metallic glasses.
Nos últimos anos, o estudo e o processamento dos vidros metálicos de grande volume (BMG Bulk Metallic Glasses), em sistemas multicomponentes, tem sido de grande interesse científico e tecnológico devido as suas propriedades únicas: como a falta de regularidade atômica de longo alcance e a sua homogeneidade composicional semelhante ao estado líquido. Estas ligas apresentam melhores propriedades mecânicas, resistência à corrosão e alta resistência à fratura quando comparado a sua contraparte cristalina. No entanto, um compreensivo entendimento físico da estrutura desordenada e de como a mesma afeta as propriedades dos vidros metálicos, ainda é considerado um dos grandes desafios na Física da Matéria Condensada e na Ciência dos Materiais. A Espectroscopia Mecânica que fornece o espectro anelástico (atrito interno e frequência de oscilação) em função da temperatura é considerada uma técnica sensível a transições de fase e a processos dinâmicos, através da qual são obtidas informações relevantes para a compreensão das alterações estruturais e vibracionais dos vidros metálicos. Neste estudo, foi utilizada a técnica de Espectroscopia Mecânica para investigar os processos dinâmicos relacionados a contribuições elásticas e eletrônicas devido aos movimentos atômicos e de cluster, bem como, as demais mudanças nas ligações atômicas nas ligas vítreas e parcialmente cristalizadas do sistema ternário Cu-Zr-Al. As amostras obtidas com base no diagrama topológico combinado λmin∙Δē foram investigadas em temperaturas acima e abaixo da temperatura ambiente (300 K) com frequências da ordem de Hz, kHz e MHz. Acima da temperatura ambiente, aplicando tensões alternadas em Hz e kHz, foi possível observar as mudanças estruturais que envolvem rearranjos atômicos devidos aos aspectos anelástico, viscoelástico e termoelástico presentes no processo de relaxação. Nesta faixa de temperatura, o caráter viscoelástico e termoelástico sobrepõe os mecanismos de relaxação anelástica que poderiam ser observados nos vidros metálicos. Em temperaturas abaixo da ambiente, as amostras de composição nominal Cu54Zr40Al6 - vítreas e nanocristalinas - mostram que os processos de relaxação anelástica se iniciam abaixo da temperatura ambiente e são dependentes da frequência aplicada. Nas frequências aplicadas em escala Hz, alguns clusters tem sua blindagem afetada pelas tensões elásticas alternadas. Quando as amostras são excitadas com uma frequência da escala de kHz surgem dois centros de relaxação bem definidos que envolvem a movimentação de clusters que tendem a ser criados e aniquilados ao mesmo tempo em que a tensão é aplicada. Em tensões aplicadas na ordem de MHz, os clusters passam a se reordenar de forma mais eficiente, de modo que, os clusters menos estáveis que envolvem o Zr são aniquilados e os clusters que possuem Al ou Cu em seu centro são reordenados de forma a promover a estabilidade da estrutura icosaédrica dentro da matriz amorfa. Conforme as energias mecânicas em MHz são aplicadas, mais estruturas estáveis são criadas de forma que os clusters tendem a aproximar, interagir e se interpenetrar dando origem aos planos de ligações livres por onde os superclusters passam a se reordenar originando cadeias de médio alcance. Com indefinidos estímulos mecânicos em MHz, as estruturas tendem a formar os primeiros precipitados cristalinos. Estes mecanismos de relaxação puramente anelástica se iniciam em baixas temperaturas, e na maioria das vezes, não são possíveis de serem observados em altas temperaturas devido ao caráter viscoelástico e termoelástico que, em geral, ocorrem simultaneamente nos vidros metálicos.
Mackie, Alexander J. „Spark Plasma Sintering as a powder processing route for pre-alloyed Sm2(Co, Fe, Cu, Zr)17 permanent magnets“. Thesis, University of Sheffield, 2017. http://etheses.whiterose.ac.uk/21654/.
Der volle Inhalt der QuelleVilela, Marcio Maia. „Medidas de poder de freamento de Si, Ti, V, Cu, Zn, Zr e Pd utilizando ions 14N e 16O“. Universidade de São Paulo, 1986. http://www.teses.usp.br/teses/disponiveis/43/43131/tde-08112013-145930/.
Der volle Inhalt der QuelleEnergy loss has been measured 14N and 16O at energies of 1 MeV/amu to 4 MeV/amu in Si, Ti, V, Cu, Zn, Zr and Pd foils. The technique consists in the measurement of the energies of ions scattered through 25 ° by a goldfoil before and after passing through the stopping foil. Our data compared to the semiempirical tabulations of Northcliffe and Schilling (N&S), Ziegler and new version of N&S by Hubert et al.. The predictions of these semiempirical compilations are in reasonable agreement with our experimental data.
Krzelowski, Mirosław. „Analiza struktury faz Laves'a Nb (Cu, Al, X) 2 (X = Ni, Co, Cr, Ti i Zr) metodą krystalografii elektronowej“. Doctoral thesis, Katowice : Uniwersytet Śląski, 2008. http://hdl.handle.net/20.500.12128/5130.
Der volle Inhalt der QuelleLin, Pin-Chen, und 林品辰. „High-Temperature Oxidation Behavior of Cu-Zr Binary and Zr-Cu-Al Ternary Bulk Metallic Glasses“. Thesis, 2010. http://ndltd.ncl.edu.tw/handle/94418180036321475320.
Der volle Inhalt der Quelle國立臺灣海洋大學
材料工程研究所
98
The oxidation behabior of three Cu-Zr based bulk metallic glasses, containing Cu64.5Zr35.5 (CZ2), Zr50Cu43Al7 (CZA7) and Zr50Cu40Al10 (CZA10) and their crystalline counterparts was studied over the temperature range of 400oC ~ 500oC in dry air. In general, the oxidation kinetics of three glassy alloys followed the two- to three-stage parabolic-rate law, indicating that diffusion is the rate-determining step during oxidation. The oxidation rate constants (kp values) gradually increasing with temperature for CZ2, but fluctuating with temperature for both CZA7 and CZA10. The scales formed on these BMGs consisted mostly of monoclinic-ZrO2 (m-ZrO2) and CuO, and minor amounts of tetragonal- and orthornombic-ZrO2 (t- and o- ZrO2). However α-Al2O3 was also detected at 500oC for CZA7 and CZA10, whose formation is responsible for the reduction of oxidation rates, as compared to those at lower temperatures. It was found that small amounts of Al addition increased glass forming ability (GFA), however, there is no reduction of the oxidation rates with respect to the binary BMG. The amorphous substrates retained unchanged at the temperature below the glass-transition temperature (Tg), however they underwent a pre-oxidation process and followed by the crystallization after oxidation at the temperature above Tg , consisting of both Cu10Zr7 and Cu51Zr14 for the CZ2 substrate, and of both Zr2Cu and Cu2ZrAl for the Al-containing ternary alloys.
Liu, Chih-Hua, und 柳智華. „Zr-Cu-Ni Phase Diagram at 800℃“. Thesis, 2004. http://ndltd.ncl.edu.tw/handle/35921417714601195951.
Der volle Inhalt der Quelle國立中山大學
材料科學研究所
92
Zirconium base alloys have very good metallic glass forming ability. In this study,the Zr-Cu-Ni ternary isotherm at 800℃ were determined by using metallography,electron-probe microanalysis and X-ray diffraction.The main objective is to provide the necessary information for alloy design to form new Zr-base with better glass forming ability.
Chen, Chih-jung, und 陳致榮. „Preparation and Characterization of Sputtered Zr-Ti and Zr-Cu Thin Film Metallic Glasses“. Thesis, 2007. http://ndltd.ncl.edu.tw/handle/2sepbs.
Der volle Inhalt der QuelleChen, Bo-Jyun, und 陳柏均. „Determination of the amorphous regions of the Cu-Zr-Ag ternary system and the phase equilibria of Cu-Zr-Ag, Cu-Al-Ag ternary systems at 500oC“. Thesis, 2012. http://ndltd.ncl.edu.tw/handle/23320511711154954591.
Der volle Inhalt der Quelle國立臺灣科技大學
材料科學與工程系
100
Bulk metallic glasses (BMGs) have attracted many interests in recent years because their strong mechanical properties, excellent corrosion resistance and good permeability. Zr-Cu based systems have high glass-forming ability (GFA)while Ag is easy to obtain. In this study, Cu-Zr-Ag alloys with different compositions were prepared, and the BMGs were produced by arc melting and copper mold. For comparison, the phase equilibria of Cu-Zr-Ag and Cu-Al-Ag ternary systems was investigated at 500oC. As the result, the best glass-forming ability (GFA) was obtained by the Cu45Zr45Ag10 alloy. In general, the amorphous region of Cu-Zr-Ag ternary system is Cu35-50Zr40-55Ag10-20. While amorphous and crystalline structures existed simultaneously in the region of Cu30-50Zr30-55Ag0-30. According to the results of phase equilibria, there were 9 single-phase regions, 15 two-phase regions and 7 three-phase regions in Cu-Zr-Ag ternary system at 500oC, and no ternary compound was found. On the other hand, in the Cu-Al-Ag ternary system, there were 8 single-phase regions, 13 two-phase regions and 6 three-phase regions but there was no ternary compound at 500oC.
„Estudo da degradação dos eletrodos Cu/Zr e Cu/Cr/Zr utilizados na soldagem de aços revestidos com Zn e liga Zn-Fe“. Tese, Biblioteca Digital de Tese e Dissertação da UFF, 1998. http://www.bdtd.ndc.uff.br/tde_busca/arquivo.php?codArquivo=1397.
Der volle Inhalt der QuelleKosiba, Konrad. „Flash-Annealing of Cu-Zr-Al-based Bulk Metallic Glasses“. Doctoral thesis, 2016. https://tud.qucosa.de/id/qucosa%3A30262.
Der volle Inhalt der QuelleZhang, Yi-zong, und 張益綜. „Zr-based and Zr-Cu based Glass-forming Films for Fatigue-property Improvements of 7075-T6 Aluminum Alloy“. Thesis, 2011. http://ndltd.ncl.edu.tw/handle/98008095198122246510.
Der volle Inhalt der Quelle國立中央大學
機械工程研究所
99
We proposed with the Zr-based and Zr-Cu based metallic glass thin film (MGTF) as promising coating for aluminum alloy fatigue property enhancement. According to the four-point-bending fatigue results, 7075-T6 aluminum alloy with a 200-nm-thick Zr-based MGTF improved its fatigue life cycle 22 times at a stress level of 250 MPa than the bare one. And the other fatigue life cycle of Zr-Cu based MGTF is further improved 44 times which ups to 107 cycles. The improvements of MGTF coating samples in fatigue limit were 235 MPa (56.7 % increase) and 250 MPa (66.7 % increase) for Zr-based and Zr-Cu based glass-forming film, respectively, and 150 MPa for uncoated sample. The films actually restrict the surface offsets and cracks propagating during the fatigue test. Zr-Cu based glass-forming film have better fatigue resistance than Zr-based MGTF, the fatigue life had improved by more than 2 times under a stress of 250 MPa, due to higher hardness and strength, better plasticity, thus it exhibits better improvement in fatigue property. A 50-nm-thick Titanium buffer layer between the film and the substrate was reported adhesion enhancement. The superior mechanical properties of MGTF, such as high strength and good bending ductility, coupled with good adhesion between the film and the substrate as well as the reduced surface roughness, and high compressive residual stress of the metallic film yield the fatigue property improvement of aluminum alloy. Thus demonstrating MGTF as promising coating materials for improving the fatigue properties of materials, and further applied to aerospace, automobile industry and bicycle manufacturing etc.
Shih, Chih-Hsiung, und 施志雄. „The measurement of Ti-Zr-Cu-Ni phase diagram at 800℃“. Thesis, 1995. http://ndltd.ncl.edu.tw/handle/76998752147969416797.
Der volle Inhalt der QuelleYang, Ta-Kai, und 楊達凱. „Effect of Sn addition on the Cu-Zr-Ti amorphous alloys“. Thesis, 2005. http://ndltd.ncl.edu.tw/handle/a2863n.
Der volle Inhalt der Quelle大同大學
材料工程學系(所)
93
This study examined the effect of Sn element addition on the Cu-Zr-Ti amorphous alloys by mechanical alloying technique. The microstructural evolution during mechanical alloying of the mixed powders was investigated by both X-ray diffraction and scanning electron microscopy (SEM).The phase stabilities of the as-milled powders were studied by DSC measurement. According to the result, after 5 hours of milling, the composition of Cu-Zr-Ti-Sn alloys were all amorphization. The thermal stability of the Cu-Zr-Ti-Sn amorphous powder was also investigated by differential scanning calorimeter (DSC). As the results demonstrated, the amorphous powder were found to exhibit a wide supercooled liquid region before crystallization. The temperature interval of the supercooled liquid region was defined by the difference between Tg and Tx. The highest value of △T was found to exhibit at Cu46Zr30Ti20Sn4 alloys system (93K). Finally, the small addition of Sn element significantly improved the glass forming ability (GFA) of Cu-Zr-Ti amorphous alloys.
Kao, Pei-Chin, und 高佩琴. „The Oxidation Behavior of Cu-Zr-Al-Ag Bulk Metallic Glasses“. Thesis, 2009. http://ndltd.ncl.edu.tw/handle/97446194829799000309.
Der volle Inhalt der Quelle國立臺灣海洋大學
材料工程研究所
97
The oxidation behavior of three Cu-Zr based bulk metallic glasses, containing Cu45Zr45Al5Ag5 (CZ45-BMG), Cu43Zr43Al7Ag7 (CZ43-BMG), and (Cu43Zr43Al7Ag7)99.5Si0.5(CZ43S-BMG) was studied over the temperature range of 375 – 500oC in dry air. The oxidation kinetics of the three glassy alloys generally followed a multi-stage parabolic-rate law, and the steady-state parabolic-rate constants (kp values) fluctuated with temperature. It was found that kp values increased with increasing temperature, when it was below the supercooled region, however, those values decreased with increasing temperature at T > 450oC. The scales formed these BMGs consisted mostly of tetragonal-ZrO2 (t-ZrO2), CuO, minor amounts of monoclinic- and orthorhombic-ZrO2, (m- and o-ZrO2), and α-Al2O3 (only detected at 500oC). The formation of α-Al2O3 was responsible for the reduction of oxidation rates of these BMGs at 500oC. ZrO2 of different structures was depended strongly on temperature and duration of time. In addition, small amounts of Ag and Si addition increased glass forming ability (GFA) and provided a better oxidation resistance at T < 425oC. However, no improvement was obtained at higher temperatures. In addition, three amorphous substrates retained unchanged at the temperature below the glass-transition temperature (Tg), however they underwent a pre-oxidation process and followed by the phase transformation after the oxidation at T > 400oC, having a dual-phase structure of Cu10Zr7 and ZrAl for both CZ45- and CZ43-BMG. On the other hand, CZ43S-BMG substrate transformed from the fully amorphous to the mostly Cu10Zr7 and minor Si2Zr crystallines. In summary, CZ45-BMG exhibited a better thermal stability among these BMGs studied.
Yang, Man-Ning, und 楊曼寧. „Fabrication and Thermal Properties of Diamond/Cu-Zr Electronic Packaging Composites“. Thesis, 2013. http://ndltd.ncl.edu.tw/handle/55661231363056225199.
Der volle Inhalt der QuelleTsai, Jian-Cheng, und 蔡建丞. „Sutdy on Zr-based amorphous alloys roll bonding with Cu sheet“. Thesis, 2018. http://ndltd.ncl.edu.tw/handle/k4p8z9.
Der volle Inhalt der Quelle義守大學
材料科學與工程學系
106
Amorphous alloys have excellent mechanical properties, but it lack of ability of plastic deformation and dutility at room temperature. In order to improve these disadvantage, there are many methods that can improve the properties have been developed. For example, thermal treatments, adding of elements, rolling and so on. Zr53Cu30Ni9Al8, this bulk metallic glasses has good glass forming ability, its γm is about 0.739 and wide supercooled liquid region, its ΔTx is about 80K. In this study, for research the working ability of bulk metallic glasses at room temperature, the Cu sheets have been chosen to place at the upside and downside of Zr53Cu30Ni9Al8 bulk metallic glasses to carry out the roll bonding to disperse stress distribution and achieve the goal of average deformation, make bulk metallic glasses and Cu sheet become a composite material. The thin metal coating slows down shear band dynamics and retards its attainment to a critical unstable state. It not only is beneficial to working of bulk metallic glasses but also can keep the thermal properties of bulk metallic glasses, that is different from warm rolling. This study also through Zr53Cu30Ni9Al8 bulk metallic glasses roll bonding with Cu sheet to investigate how the process of roll bonding influence the effet of roll bonding, like surface treatments, the rolling direct of roll bonding, the reduction rate of roll bonding and the thickness of bulk metallic glasses.
Xie, Sujing. „Plastic Deformation and Annealing of Zr- and Cu- Based Bulk Metallic Glasses“. 2007. http://etd.utk.edu/2007/XieSujing.pdf.
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