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Master's Dissertation
DOI
10.11606/D.3.2007.tde-01042008-175024
Document
Author
Full name
Rodrigo Camargo Campana
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2007
Supervisor
Committee
Plaut, Ronald Lesley (President)
Gonçalves, Marcelo
Padilha, Angelo Fernando
Title in Portuguese
Parâmetros de processo, microestrutura e textura das ligas de aluminio AA6063 e AA6082 extrudadas.
Keywords in Portuguese
Alumínio
Extrusão
Zener-Hollomon
Abstract in Portuguese
O desenvolvimento de ligas de alumínio de propriedades mecânicas intermediárias possibilitou a extrusão de alumínio a participar de grandes mercados como a construção civil, transportes, automobilística, estruturas, entre outras. O conhecimento do processo de extrusão propicia o aumento de produtividade com melhor desempenho e precisão dimensional do produto acabado. Neste trabalho, procurou-se analisar as características de conformação de perfis sólidos das ligas de alumínio AA6063 e AA6082 com razão de extrusão (RE) variando de 2,0 a 27,8 e tubular com RE de 8,7. A partir da extrusão realizada em uma prensa industrial de 3300 toneladas de força, compararam-se os resultados obtidos da tensão média de escoamento ("sigma") em função da temperatura de deformação e do parâmetro de Zener-Hollomon (Z) e este último em função do tamanho de subgrão observado no produto extrudado. Foram obtidos, em condições industriais, para estas ligas os valores da constante "alpha" que relaciona a RE com a pressão de fim de extrusão. Foram realizadas observações metalográficas e constatadas regiões de recristalização e de não recristalização diferentes para as ligas estudadas, bem como as relações do parâmetro Z e o tamanho do subgrão do produto sólido e tubular na liga AA6082. Em termos de textura foi possível obter as figuras de pólo e do tipo FDO no perfil extrudado ilustrando a presença de fibras do tipo "beta" (característica de produto conformado) e cubo (característica de produto recristalizado/recuperado). Os resultados confirmam valores próximos àqueles encontrados na literatura.
Title in English
Process parameter, Mycroestructure and Texture of Extruded AA6063 and AA6082 Profiles
Keywords in English
Aluminum
Extrusion
Texture
Zener-Hollomon
Abstract in English
The development of medium strength aluminum alloys enabled aluminum extrusions to take part of the large world markets, associated with the building, transport and automotive industries, amongst several applications. The knowledge of the extrusion process details enables the productivity increase with better performance and higher dimensional accuracy of the finished extrusion product. In the present study the deformation characteristics of solid extrusion profiles in the AA6063 and AA6082 alloys with extrusion ratios (ER) in the range of 2.0 to 27.8 and for solid and tubular of 8.7 sections were studied. Extrusions were carried out in an industrial 3300 ton press. Results are compared in terms of average flow stress as a function of extrusion temperature and of the Zener-Hollomon (Z) parameter; the latter one also as a function of the observed subgrain size in the final product. Under industrial conditions, for the studies alloys, the values of the "alpha"-constant (which relates the end pressure to the extrusion ratio), has been evaluated. Metallographic observations have been conducted to study the recrystallised and unrecrystallised regions in the studied alloys, as well as the relationship between the Z parameter and the subgrain size of the end extrusion, both for the solid and tubular products, mainly for the AA6082 alloy. In terms of texture components it has been observed that the pole figures and the ODF´s of the extruded product presented the "beta" (characteristic of rolled/worked products) and cube (characteristic of recrystallised/recovered products). The results obtained confirmed those reported in the literature.
 
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Publishing Date
2008-04-03
 
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