Kinetic equation parameters for the curing reaction of a commercial glass fiber reinforced high performance epoxy prepreg composed of the tetrafunctional epoxy tetraglycidyl 4,4-diaminodiphenyl methane (TGDDM), the tetrafunctional amine curing agent 4,4'-diaminodiphenylsulfone (DDS) and an ionic initiator/accelerator, are determined by various thermal analysis techniques and the results compared. The reaction is monitored by heat generated determined by differential scanning calorimetry (DSC) and by high speed DSC when the reaction rate is high. The changes in physical properties indicating increasing conversion are followed by shifts in glass transition temperature determined by DSC, temperature-modulated DSC (TMDSC), step scan DSC and high speed DSC, thermomechanical (TMA) and dynamic mechanical (DMA) analysis and thermally stimulated depolarization (TSD). Changes in viscosity, also indicative of degree of conversion, are monitored by DMA. Thermal stability as a function of degree of cure is monitored by thermogravimetric analysis (TGA). The parameters of the general kinetic equations, including activation energy and rate constant, are explained and used to compare results of various techniques. The utilities of the kinetic descriptions are demonstrated in the construction of a useful time-temperature-transformation (TTT) diagram and a continuous heating transformation (CHT) diagram for rapid determination of processing parameters in the processing of prepregs. Shrinkage due to both resin consolidation and fiber rearrangement is measured as the linear expansion of the piston on a quartz dilatometry cell using TMA. The shrinkage of prepregs was determined to depend on the curing temperature, pressure applied and the fiber orientation. Chemical modification of an epoxy was done by mixing a fluorinated aromatic amine (aniline) with a standard aliphatic amine as a curing agent for a commercial Diglycidylether of Bisphenol-A (DGEBA) epoxy. The resulting cured network was tested for wear resistance using tribological techniques. Of the six anilines, 3-fluoroaniline and 4-fluoroaniline were determined to have lower wear than the unmodified epoxy, while the others showed much higher wear rates.

A proposta de desenvolvimento deste trabalho de dissertação veio de encontro com o objetivo de adaptar um laboratório para pesquisas em transformações de fases, utilizando o método dilatométrico, onde foram estudadas as reações no estado sólido que sofrem os materiais submetidos a ciclos térmicos. Para atingir este objetivo, instalou-se recentemente um dilatômetro de resfriamento rápido, modelo DT 1000 da Adamel Lhomargy. Completada a etapa de instalação do equipamento, o passo seguinte consistiu em explorar, através de ciclos térmicos variados, todos os recursos manipuláveis do dilatômetro. Aplicando a técnica dilatometrica em um aço de características termomecânicas conhecidas - SAE 1070 - possibilitou-se, a partir deste trabalho, que pesquisas mais complexas pudessem ser executadas com tal equipamento ou que o mesmo servisse como um instrumento complementar para estudos de transformações de fases. Nessa fase inicial de investigações estudou-se as curvas dilatométricas a fim de verificar os tempos de início e fim de transformação isotérmica em várias temperaturas de decomposição da austenita. Traçou-se as curvas de transformação isotérmica - curvas TTT - para o aço ensaiado (tratado termicamente), onde analisou-se a influência desse tratamento térmico prévio (recozimento) sobre a transformação \'alfa\' para \'gama\'. Finalizando a parte prática deste trabalho, comprovou-se as transformações de fases isotérmicas nas várias temperaturas ensaiadas, através de análise metalográfica e de medidas de microdureza dos produtos obtidos. A fim de solucionar eventuais problemas relacionados ao manuseio e manutenção do equipamento, com base na experiência adquirida ao longo do desenvolvimento deste trabalho, são dadas sugestões de possíveis aplicações do dilatômetro de têmpera rápida DT 1000 em pesquisas de transformações de fases. / The purpose of this work comes together with the objective to adapt a phase transformation research laboratory using dilatometric method, where it will be possible to study the solid state reactions of materials submited to thermal cycles. To fulfil this purpose, it was installed a high speed quenching dilatometer, model DT 1000 manufactured by Adamel Lhomargy. After this stage, our next step was to explorer all equipment resources through variable thermal cycles. Appling dilatometric method to a well known thermomechanical steel - SAE 1070 - it becomes possible the accomplishment of more complex experiments with this equipment. This equipment, itself, may be a powerfull auxilliary instrument to phase transformations studies. In this first investigation, it was studied the dilatometric curves to find the beginning and the end times of isothermal phase transformation for several austenite decomposition temperatures - TTT diagram - for the tested steel (thermal treated). The effect of this previous heat treatment (annealing) on the \'alfa\' for \'gama\' transformation were observed. Finally, the isothermal phase transformation at the different tested temperatures could be confirmed through metallographic and microhardness analysis. In order to solve possible problems associated to the equipment use or maintenance, some suggestions of applications of the high speed quenching dilatometer are indicated for further works.

A proposta de desenvolvimento deste trabalho de dissertação veio de encontro com o objetivo de adaptar um laboratório para pesquisas em transformações de fases, utilizando o método dilatométrico, onde foram estudadas as reações no estado sólido que sofrem os materiais submetidos a ciclos térmicos. Para atingir este objetivo, instalou-se recentemente um dilatômetro de resfriamento rápido, modelo DT 1000 da Adamel Lhomargy. Completada a etapa de instalação do equipamento, o passo seguinte consistiu em explorar, através de ciclos térmicos variados, todos os recursos manipuláveis do dilatômetro. Aplicando a técnica dilatometrica em um aço de características termomecânicas conhecidas - SAE 1070 - possibilitou-se, a partir deste trabalho, que pesquisas mais complexas pudessem ser executadas com tal equipamento ou que o mesmo servisse como um instrumento complementar para estudos de transformações de fases. Nessa fase inicial de investigações estudou-se as curvas dilatométricas a fim de verificar os tempos de início e fim de transformação isotérmica em várias temperaturas de decomposição da austenita. Traçou-se as curvas de transformação isotérmica - curvas TTT - para o aço ensaiado (tratado termicamente), onde analisou-se a influência desse tratamento térmico prévio (recozimento) sobre a transformação \'alfa\' para \'gama\'. Finalizando a parte prática deste trabalho, comprovou-se as transformações de fases isotérmicas nas várias temperaturas ensaiadas, através de análise metalográfica e de medidas de microdureza dos produtos obtidos. A fim de solucionar eventuais problemas relacionados ao manuseio e manutenção do equipamento, com base na experiência adquirida ao longo do desenvolvimento deste trabalho, são dadas sugestões de possíveis aplicações do dilatômetro de têmpera rápida DT 1000 em pesquisas de transformações de fases. / The purpose of this work comes together with the objective to adapt a phase transformation research laboratory using dilatometric method, where it will be possible to study the solid state reactions of materials submited to thermal cycles. To fulfil this purpose, it was installed a high speed quenching dilatometer, model DT 1000 manufactured by Adamel Lhomargy. After this stage, our next step was to explorer all equipment resources through variable thermal cycles. Appling dilatometric method to a well known thermomechanical steel - SAE 1070 - it becomes possible the accomplishment of more complex experiments with this equipment. This equipment, itself, may be a powerfull auxilliary instrument to phase transformations studies. In this first investigation, it was studied the dilatometric curves to find the beginning and the end times of isothermal phase transformation for several austenite decomposition temperatures - TTT diagram - for the tested steel (thermal treated). The effect of this previous heat treatment (annealing) on the \'alfa\' for \'gama\' transformation were observed. Finally, the isothermal phase transformation at the different tested temperatures could be confirmed through metallographic and microhardness analysis. In order to solve possible problems associated to the equipment use or maintenance, some suggestions of applications of the high speed quenching dilatometer are indicated for further works.

En este trabajo de investigación se ha estudiado la influencia de algunos copolimeros de butadieno y acrilonitrilo sobre el curado de una resina epoxi y sobre las propiedades térmicas y termomecánicas de los materiales compuestos resultantes. Mediante curados isotérmicos se ha investigado utilizando la calorimetria diferencial de barrido (dsc) la influencia que tiene la adición de estos copolímeros sobre el curado de la resina epoxi. A partir de las diferentes experiencias se ha hallado en función del tiempo la temperatura de transición vitrea (tg) y el grado de conversión. Estos resultados han permitido obtener el tiempo de vitrificación, el grado de conversión cuando el material vitrifica y la tgoo (la mayor tg que puede tener el sistema) para los diferentes sistemas estudiados.Se ha analizado la cinetica del proceso de curado mediante diferentes metodos isotérmicos y dinámicos utilizando la tecnica DSC. Se han obtenido valores de energia de activación y de factor de frecuencia de los sistemas empleados. La relación experimental entre la tg y el grado de conversión se ha ajustado mediante la ecuación de dibenedetto.Utilizando el análisis termomecánico (tma) ha podido observarse el fenómeno de la gelificación y se ha determinado mediante la técnica dsc el grado de conversión cuando el material gelifica. Con estos datos y con los cineticos obtenidos anteriormente se han podido construir los diagramas ttt (tiempo-temperatura-transformación).Se ha estudiado el fenómeno del envejecimiento físico en muestras parcialmente curadas de resina epoxi pura y de esta misma resina con diferentes proporciones de ctbn31.Se ha investigado la solubilización del plastificante contenido en el endurecedor por parte de los elastómeros y la solubilidad existente entre la base epoxi y los copolímeros. Mediante el análisis térmico-dinámico-mecánico (dmta) se ha observado la separacion de fases existentes en los diferentes sistemas estudiado.

Avaliou-se experimentalmente o ferro fundido branco de alto-cromo-molibdênio ao qual foi adicionado nióbio, a respeito de sua temperabilidade. Dilatometricamente traçou-se a curva TTT desse material, bem como a de um ferro fundido branco de alto cromo para efeito comparativo. Constatou-se por essa comparação e pelos resultados da literatura a alta temperabilidade obtida pela liga experimental. A partir da temperatura de austenitização utilizada, podem-se usar taxas de resfriamento de até 0,12°C/s sem transformação de fase, enquanto que na liga comparativa essa taxa aumenta para 5,8°C/s. Foram realizadas análises de desgaste abrasivo, de dureza e microdureza, de difração por raios-X , de fase magnética e de microanálise como forma de caracterizar as transformações de fase observadas por dilatometria. As variações estruturais decorrentes dos tratamentos térmicos realizados nas duas ligas foram acompanhados por microscopia ótica. É indicativo pelo presente trabalho que tal material além de suas características inerentes de resistência à abrasão e à corrosão oferece maior flexibilidade nos projetos que envolvam paredes espessas. / In this work we studied the hardenability of high chromium- molibdenum white cast iron with niobium. By dilatometry we obtained the TTT curve of this material as well as the high chromium white cast iron for comparison. This comparison and available results in literature confirm the high temperability of experimental material. We can use slow rate cooling 0,12°C/s or higher without phase transformation, while in the comparative alloy this rate is around 5,8°C/s or higher from specific used austenitic abrasive temperature. We also realized analysis of abrasive wear, hardness and microhardness, raios-X difraction, magnetic phase and microanalyse for verifing the phase transformation as observed by dilatometry. The structure variation as function of termic treatment in both alloys is monitored by optical microscope. The present work indicate that the material under study can offer more flexibility for projects with thick materials apart from intrinsic characteristics of abrasive wear and corrosion.

Avaliou-se experimentalmente o ferro fundido branco de alto-cromo-molibdênio ao qual foi adicionado nióbio, a respeito de sua temperabilidade. Dilatometricamente traçou-se a curva TTT desse material, bem como a de um ferro fundido branco de alto cromo para efeito comparativo. Constatou-se por essa comparação e pelos resultados da literatura a alta temperabilidade obtida pela liga experimental. A partir da temperatura de austenitização utilizada, podem-se usar taxas de resfriamento de até 0,12°C/s sem transformação de fase, enquanto que na liga comparativa essa taxa aumenta para 5,8°C/s. Foram realizadas análises de desgaste abrasivo, de dureza e microdureza, de difração por raios-X , de fase magnética e de microanálise como forma de caracterizar as transformações de fase observadas por dilatometria. As variações estruturais decorrentes dos tratamentos térmicos realizados nas duas ligas foram acompanhados por microscopia ótica. É indicativo pelo presente trabalho que tal material além de suas características inerentes de resistência à abrasão e à corrosão oferece maior flexibilidade nos projetos que envolvam paredes espessas. / In this work we studied the hardenability of high chromium- molibdenum white cast iron with niobium. By dilatometry we obtained the TTT curve of this material as well as the high chromium white cast iron for comparison. This comparison and available results in literature confirm the high temperability of experimental material. We can use slow rate cooling 0,12°C/s or higher without phase transformation, while in the comparative alloy this rate is around 5,8°C/s or higher from specific used austenitic abrasive temperature. We also realized analysis of abrasive wear, hardness and microhardness, raios-X difraction, magnetic phase and microanalyse for verifing the phase transformation as observed by dilatometry. The structure variation as function of termic treatment in both alloys is monitored by optical microscope. The present work indicate that the material under study can offer more flexibility for projects with thick materials apart from intrinsic characteristics of abrasive wear and corrosion.

Heat treatment can be defined as a combination of heating and cooling operations applied to a metal or alloy in solid state. It is an important manufacturing process, which controls the mechanical properties of metals, therefore contributes to the product quality. Computerized Heat Treatment Planning System for Quenching and Tempering (CHT-q/t), a windows based stand alone software, is developed to assist the heat treatment process design. The goal of CHT-q/t is to predict the temperature profile of load in batch as well as continuous furnace during heating, quenching and tempering of steel, then to predict the mechanical properties as Quenched & Tempered, and finally to optimize the heat treatment process design. The thesis reviews existing heat treating simulation software and identifies the industrial need of a software tool which integrates part load and furnace model with heat treating process. The thesis discusses cooling curve of specimen and Time Temperature Transformation (TTT) diagram to determine the microstructure evolution and subsequently the mechanical properties of steel after quenching. An extensive database has been developed to support the various function modules. The thesis focuses mainly in the TTT and quenchant database development, property prediction after quenching and tempering and the implementation of software. The properties determined in the thesis are hardness, ultimate tensile strength, yield strength, toughness and percentage elongation. Hardness has been predicted by the use of some well known analytical equations and the TTT database, finally regression analysis has been used to give the value as a function of carbon percentage and volume fraction of martensite. The other mechanical properties are calculated based on a relation of hardness and volume fraction of martensite. Various case studies were performed to show the application of CHT-bf and CHT-cf at Bodycote Thermal Processing, Worcester & Waterbury. The objective behind the case studies was to study the effect of change in load arrangement, production rate and cycle time on the heat treated parts and finally to give recommendations in order to save energy and improve productivity and quality.

NiTi components are commonly subjected to thermo-mechanical heat treatments during production and fabrication. This study investigates the effects of applied strain of 0-10% and heat treatments of 300-600ºC for times of 2-30 minutes during shape-setting of Ti–50.8 at% Ni wire with a nominal diameter of 0.495 mm and an initial transition temperature, Af, of 12ºC. Strain was applied prior to heat treatments by coiling NiTi wire, essentially producing coiled springs, around different diameter steel mandrels to obtain different strain levels. The samples of NiTi wire under applied strain were heat treated in a salt bath, followed by a rapid quench. Transformation temperatures and mechanical properties were characterized using the differential scanning calorimeter and tensile tests. Changes in the Af, UTS, and elastic modulus due to ageing processes and applied strain were observed. Following theory, precipitation rates of Ni-rich phases generally increased with increased temperature (up to a certain point), time and applied strain levels. Reaction rates to achieve a particular Af might be faster than expected if the sample is under strain during the shape-setting process. Due to precipitation strengthening, an increase in UTS with increased heat treatment time was observed between 300-450°C; annealing processes dominate at higher temperatures, resulting in a decrease in UTS above 500°C. A decrease in UTS with increasing level of applied strain was observed. Trends in elastic modulus were highly inconsistent in this study. As shown by this study, applied strain in NiTi during heat treatment affects the Af and mechanical properties.

Cette thèse porte sur l'étude rhéocinétique de deux systèmes époxy/amine, DGEBA/DETDA et DGEBA/IPD pour le rotomoulage réactif. Les paramètres cinétiques du mécanisme auto-catalytique et non catalytique de la réticulation isotherme ont été identifiés par une méthode inverse à l'aide des résultats du suivi cinétique par spectroscopie proche infra rouge (PIR). La différence du comportement rhéocinétique entre les deux systèmes est attribuée à la différence de réactivité intrinsèque des groupes amines mis en jeu et l'importance de l'effet de substitution (réactivité des amines primaires par rapport aux amines secondaire) des deux durcisseurs. Une nouvelle méthode de détermination de l'effet de substitution a été établie, en utilisant les taux de conversion de l'époxy et de l'amine primaire mesurées par PIR. L'analyse des phénomènes de vitrification et gélification des deux systèmes a permis d'établir le diagramme Temps-Température-Transformation (TTT). La comparaison de la rotomoulabilité des deux systèmes a été effectuée par l'ajout des courbes d'iso-viscosité sur le diagramme TTT. L'écoulement au cours du rotomoulage a été modélisé par un écoulement à surface libre sous gravité d'un fluide réactif à l'intérieure d'un cylindre horizontal en rotation autour de son axe principal. Dans le cas des fluides de viscosité faible, la méthode lagrangienne de Smoothed Particle Hydrodynamics SPH, a été appliquée en utilisant une expression adaptée de la viscosité.

本篇研究以台灣首檔指數股票型基金(Exchange Traded Fund)-台灣卓越50證券投資信託基金，台灣證券交易所股票交易代碼0050，英文名稱：Taiwan Top50 Tracker Fund (簡稱TTT)為研究對象，以個案研究方式探討其在台灣當時之市場環境下在短期內進行多項法規修訂與首創獨步全球的集合實物申購機制，促成其資產規模的成長創下世界紀錄，由上市時的42.87億元，至2004年6月30日達448.61億，短短1年的時間，資產規模增加10.46倍；而基金單位數也持續成長至1,003百萬個單位，較掛牌時的116百萬個單位也大幅成長8.65倍。而該產品開發團隊發展出全球首創之『集合實物申購』初級市場營運模式，順利讓政府相關特殊基金得以將其部份持有股票進行轉換，使得台灣50指數ETF中65.6%的基金資產規模源自於此，本次報告將分析及證明其關鍵地位。