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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

InfluÃncia do Resfriamento sub-zero apÃs o Envelhecimento na FormaÃÃo de Austenita Revertida em um AÃo Maraging 350 / Influence of sub-zero cooling after the formation of austenite on Aging Reversed in a maraging steel 350

Henrique Thiago Freire de Menezes 29 September 2008 (has links)
FundaÃÃo de Amparo à Pesquisa do Estado do Cearà / Os aÃos maraging sÃo materiais de ultra-alta resistÃncia sendo composto principalmente por uma base quaternÃria Ni-Co-Mo-Ti que possuem excelente tenacidade aliada com alta resistÃncia mecÃnica sendo utilizadas na indÃstria bÃlica, nuclear, componentes aeronÃuticos, vasos de pressÃo atà indÃstria esportiva. Uma de suas importantes aplicaÃÃes à na utilizaÃÃo nos motores de histerese os quais necessitam de materiais com caracterÃsticas de materiais magneticamente macios e elevada resistÃncia mecÃnica. Foram realizados ensaios de microdueza para determinar propriedades mecÃnicas nas diversas condiÃÃes de tratamento de envelhecimento e meios de resfriamento. Com o objetivo de descobrir as fases presentes no material nas diversas condiÃÃes de tratamento foram realizadas ensaios por difraÃÃo de raios-X bem como analisar a macrotextura atravÃs de FDOC`s. A microtextura foi analisada atravÃs da tÃcnica de EBSD (Electron Backscatterig Diffraction) com o intuito de estudar a influÃncia da textura da austenita na martensita nas determinadas condiÃÃes de envelhecimento e meios de resfriamento. Esta dissertaÃÃo à de grande relevÃncia para o desenvolvimento de novos produtos utilizando aÃos maraging, pois determina as condiÃÃes que oferecem as propriedades mecÃnicas, bem como as fases e textura presentes no material nas condiÃÃes de tratamento requeridas. / Maraging steels are materials of ultra high strength mainly composed of a base quaternary Ni-Co-Mo-Ti which have excellent toughness combined with high mechanical strength being used in war industry, nuclear, aircraft components, pressure vessels up to the sports industry . One of its important applications is in use in hysteresis motors which require materials with characteristics of magnetically soft materials and high mechanical strength. Microdueza tests were performed to determine mechanical properties in different treatment conditions of aging and cooling media. In order to discover the phases present in the material conditions in the various treatment trials were performed by X-ray diffraction as well as analyze the macrotexture through FDOC `s. The microtexture was examined using the technique of EBSD (Electron Diffraction Backscatterig) in order to study the influence of the texture of the austenite in the martensite aging in certain conditions and means of cooling. This thesis is of great importance for the development of new products using maraging steel, because it determines the conditions that provide the mechanical properties as well as the phases and texture present in the material conditions of treatment required.

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