Thèse (M.Eng.) -- Université du Québec à Chicoutimi, 2003. / Bibliogr.: f. 123-126. Document électronique également accessible en format PDF. CaQCU

Thèse (D.Eng.) -- Université du Québec à Chicoutimi, 2004. / Bibliogr.: f. 170-179. Document électronique également accessible en format PDF. CaQCU

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-11-06T13:51:15Z No. of bitstreams: 1 arthurchavessimoes.pdf: 3001799 bytes, checksum: a2f4926991dd99102df0b0e14c168d37 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-11-09T14:22:05Z (GMT) No. of bitstreams: 1 arthurchavessimoes.pdf: 3001799 bytes, checksum: a2f4926991dd99102df0b0e14c168d37 (MD5) / Made available in DSpace on 2017-11-09T14:22:05Z (GMT). No. of bitstreams: 1 arthurchavessimoes.pdf: 3001799 bytes, checksum: a2f4926991dd99102df0b0e14c168d37 (MD5) Previous issue date: 2017-08 / O presente trabalho teve como objetivo, avaliar a influência do tempo de condicionamento com ácido fluorídrico nas concentrações de 5% e 10%, sobre a resistência de união entre uma cerâmica Y-TZP vitrificada e um cimento resinoso. Blocos pré-sinterizados de cerâmica Y-TZP (IPS e.max® ZirCAD – Ivoclar Vivadent) foram cortados para obtenção de 70 blocos, sendo que cada pastilha recebereu dois corpos de prova. Previamente à sinterização, os blocos foram regularizados com lixas d’água de granulação #180, #600 e #1200. Eles foram então divididos aleatoriamente em sete grupos, sendo um o grupo controle no qual foi realizada a silicatização com Rocatec Soft e um grupo no qual os blocos receberam uma camada de glaze spray Vita Akzent Plus, e foram condicionada com o ácido fluorídrico (Condac Porcelana) por 5, 10 ou 20 segundos na superfície destinada à adesão. Para cimentação foi utilizado o agente de união Relyx Ceramic Primer e um cimento resinoso dual (Relyx ARC). Em cada bloco foram obtidas duas colunas de cimento, totalizando 20 amostras por grupo. Após 5000 ciclos de termociclagem, o teste de cisalhamento foi realizado (EMIC, DL 2000), a resistência de união foi registrada e utilizada para cálculo da resistência adesiva. Além disso, a análise de falha também foi realizada em todas as amostras com um estereomicroscópio (Stemi 2000-C), revelando 100% de falhas adesivas. Para avaliar a influência do tratamento de superfície na resistência de união, os dados obtidos neste estudo foram submetidos ao modelo estatístico da análise de variância (Kruskal-Wallis), após ser considerada a distribuição dos resíduos, foi determinado que os dados originais não propiciaram um adequado ajuste, pois os dados não se ajustam a uma distribuição normal de probabilidade. O teste Kruskal-Wallis revelou que houve um efeito de interação significativa, o que indica que houve alteração da resistência de união em razão do tratamento de superfície (p valor=0,001). / The objective of the present study was to evaluate the influence of the conditioning time with 5% and 10% hydrofluoric acid on the bond strength between a vitrified Y-TZP ceramic and a resin cement. Pre-sintered ceramic blocks Y-TZP (IPS e.max® ZirCAD - Ivoclar Vivadent) were cut to obtain 70 blocks, with each insert received two samples. Prior to sintering, the blocks were regularized with grit silicon carbide papers #180, #600 and #1200. They were then divided randomly into seven groups, one being the control group in which the silicatization was performed with Rocatec Soft and a group in which the blocks received a layer of Vita Akzent Plus glaze spray, and were conditioned with hydrofluoric acid (Condac Porcelana) at a concentration of 5% and 10% for 5, 10 or 20 seconds on the adhesion surface. For cementation, Relyx Ceramic Primer and a dual resin cement (Relyx ARC) were used. In each block two cement columns were obtained, totaling 20 samples per group. After 5000 cycles of thermocycling, the shear test was performed (EMIC, DL 2000), bond strength was recorded and used to calculate the adhesive strength. In addition, failure analysis was also performed on all samples with a stereomicroscope (Stemi 2000-C), revealing 100% adhesive failures. In order to evaluate the influence of the surface treatment on the bond strength, the data obtained in this study were submitted to the statistical analysis of variance (Kruskal-Wallis test), after considering the distribution of residues, it was determined that the original data did not provide an adequate adjustment because the data did not fit a normal probability distribution. The Kruskal-Wallis test revealed that there was significant interaction effect, indicating that there was change in bond strength due to surface treatment (p value = 0.001).

This thesis is in support of my Master of Fine Arts exhibition in the Carroll Reece Museum at East Tennessee State University. It describes a body of work that strives for a balance of form and aesthetics. Chapter 1 charts how I refined my personal stylistic qualities. Chapter 2 gives a brief overview of the history of ceramics techique. Chapter 3 discusses the surface treatment and construction of the pieces in the show. Chapter 4 presents each piece in chronological order.

Ce travail porte sur l'étude du comportement sous sollicitation de fretting sirnple à haute température de superalliages monocristallins à base de nickel MC2 et CMSX-4. Il trouve son application dans le domaine aéronautique, plus précisément au niveau de la turbine haute pression des moteurs d'hélicoptère. Celle-ci a pour fonction de convertir l'énergie cinétique des gaz brûlés en un couple qui entraîne en rotation le compresseur. Elle participe ainsi directement à l'entretien du cycle de combustion du moteur ce qui fait d'elle un organe clé. Située directement en aval de la chambre de combustion, la turbine haute pression (HP) est composée d'un disque central polycristallin et d'aubages monocristallins rapportés, liés au disque par une liaison dite pied de sapin. La rotation de la turbine et la température élevée des gaz de combustion va générer sur les aubes, le disque et l'attache qui les relie，des sollicitations thermomécaniques importantes. Du fait de la force centrifuge et du défilement des aubes devant les étages fixes des distributeurs, l'attache pied de sapin est la cible d 'oscillations dynamiques à l'origine de phénomènes d'endommagement par fretting. Ce fretting,, l'interface de contact entre l'aube et le disque fait l'objet d'une attention toute particulière，ce qui a motivé la conduite de ces travaux. Après une première phase et développement et de validation d'un banc d'essai innovant qui a nécessité la mise en place d'un dispositif de chauffage par induction, un soin tout particulier est apporté à la préparation des échantillons. La nature monocristalline du matériau constitutif des aubes nécessite en effet de respecter précisément l'orientation de la microstructure par rapport aux axes de sollicitation et la surface de contact. Pour cela une mesure systématique de la désorientation des axes primaires et secondaires des barreaux bruts est réalisée. La désorientation relevée est ensuite compensée au cas par cas lors du prélèvement par électroérosion des échantillons. Le lot d'échantillons obtenu peut dès lors être considéré comme homogène en terme d'orientation, malgré le fait que les barreaux bruts présentent des désorientations différentes. [...] / The aim of this work is to study the behavior of MC2 and CMSX-4 nickel based superalloys when subjected to fretting load at high temperature. Since it drives the compressor shaft, the high pressure turbine is a key part of the helicopter engine. 1n order to increase the global reliability and efficiency of the engine, single crystal nickel based superalloys are employed for turbine blades while disk parts are made of polycrystalline materials. Each turbine blade is attached to the central disk via a special link called fir tree root. Due to high temperature and dynamic oscillations, the contact zone between blades and disk is subjected to high thermomechanical stresses. 1t causes fretting phenomena that can lead to wear and cracking damage. This work focuses on both the partial slip and gross slip regime in order to study the damage process of single crystal MC2 and CMSX-4 materials. To perform the mechanical tests, an innovative fretting device is designed to fit the specifications. The use of an induction heat system allows an accurate control of high temperatures. To be consistent with the real flying parts,，the specific orientation of the microstructure of the material with respect to the contact loading direction is taken into account. The microstructure misalignement of raw material bars is measured and compensated as the specimens are machined for extraction. Consequently the obtained set of samples is considered to be of homogeneous microstructure orientation even if their source material contains deviations in orientation. Four material states are investigated: precision grinding conventional shot-peening ultrasonic shot-peening and nitriding process. The results show that for the partial slip régime, shot peening processes are very useful for turbine blade applications. As a matter of fact, the risk for crack nucleation and extension are reduced by the introduction of residual stresses beneath the surface in spite of the high temperature. 1nvestigating the gross slip regime results show that wear of material leads to the formation of a third body and then to the formation of a thin layer called "glaze layer)) with low friction coefficient. To describe the formation process of the "glaze layer)) halted trials are performed. The results allow the drafting of a scenario in which wear debris are stuck and sintered beneath the contact.

Memoire (M. Sc. A.)-- Universite du Quebec a Chicoutimi, 1984. / Bibliographie: f. 109-114. Document électronique également accessible en format PDF. CaQCU

Mémoire (M. Sc.A.)-- Université du Québec à Chicoutimi, 1985. / Bibliogr.: f. [94]-99. Document électronique également accessible en format PDF. CaQCU

Thèse (M.Eng.) -- Université du Québec à Chicoutimi, programme extensionné a l'Université du Québec à Rimouski, 2004. / Bibliogr.: f. 97-104. Document électronique également accessible en format PDF. CaQCU

Thèse (M.Eng.) -- Université du Québec à Chicoutimi, programme extensionné à l'Université du Québec à Rimouski, 2004. / Bibliogr.: f. 147-150. Document électronique également accessible en format PDF. CaQCU

Thèse (D.Eng.) -- Université du Québec à Chicoutimi, 2004. / Bibliogr.: f. [183]-197. Document électronique également accessible en format PDF. CaQCU