Estudo do comportamento mecÃnico da liga de alumÃnio AA 8011 em diferentes seqÃÃncias termomecÃnicas

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

Sheets and foils of AA 8011 aluminum alloy, among other properties, exhibit a typical mechanical behavior in which formability and mechanical strength establish a good compromise, which is normally not encountered in other commercial aluminium alloys. These characteristics make possible use of this aluminum alloy in different products as alimentary packaging, domestic appliances, automobile components and so on. The ASTM B209M-01, NBR 7823 and AA-Aluminum Association standards used to establish the limits of the mechanical properties in sheets and foils are not yet concluded for this AA 8011 aluminum alloy. The EN456-2 1996 standard has only the limiting values of the mechanical properties for sheets in hardened and annealed conditions about at 0.006mm to 0.089mm and 0.035mm to 0.20mm. The objective of this study is to know the mechanical behavior AA 8011 aluminum alloy produced by heat treatments in different thermo-mechanical routes which is not known yet. By this study, the limits between formability and mechanical properties can be established. In other hands, the potential applications can be exploited by increasing the range of new products in secondary industries. A relation between mechanical properties and related microstructure will be established in different thermal sequences. In this form relation between formability and mechanical resistance will be optimized to increase the potential of this alloy for various applications. In this work nine samples of sheets of about 5,0mm thickness of the AA 8011 alloy, produced in different twin-roll casting conditions, were analyzed considering the influence of the other parameters. Sample of these sheets were deformed by cold-rolling for producing the sheets of 2,0mm, 1,0mm and 0,5mm thickness. Following cold-rolling, these sheets were heat treated at 220ÂC up to 400ÂC for 3 hours After heat treatments, sheets of 2,0mm, 1,0mm and 0,5mm were deformed by cold-rolling up to 0,2mm thickness. Finally, these foils of 0,2 mm thickness were heat-treated and analyzed and their mechanical properties were established. In this study nine samples of sheets of about 5,0mm thickness of the AA 8011 alloy, produced in different twin-roll casting conditions, were analyzed considering the influence of the other parameters. Sample of these sheets were deformed by cold-rolling for producing the sheets of 2,0mm, 1,0mm and 0,5mm thickness. Following cold-rolling, these sheets were heat treated at 220ÂC up to 400ÂC for 3 hours After heat treatments, sheets of 2,0mm, 1,0mm and 0,5mm were deformed by cold-rolling up to 0,2mm thickness. Finally, these foils of 0,2 mm thickness were heat-treated and analyzed and their mechanical properties were established. In conclusion, the results showed that the mechanical properties are very sensible to thermomechanical routes. By the stress and strain tests of the samples produced in different conditions ], in terms of level of deformation and thermo-mechanical treatments, it became possible to characterize the conditions and mechanical properties of this alloy. Ericksen tests were carried out in some samples selected apart from the strategic points (significant change in mechanical properties) of the mechanical behavior curve of the alloy. In this study nine samples of sheets of about 5,0mm thickness of the AA 8011 alloy, produced in different twin-roll casting conditions, were analyzed considering the influence of the other parameters. Sample of these sheets were deformed by cold-rolling for producing the sheets of 2,0mm, 1,0mm and 0,5mm thickness. Following cold-rolling, these sheets were heat treated at 220ÂC up to 400ÂC for 3 hours After heat treatments, sheets of 2,0mm, 1,0mm and 0,5mm were deformed by cold-rolling up to 0,2mm thickness. Finally, these foils of 0,2 mm thickness were heat-treated and analyzed and their mechanical properties were established. In conclusion, the results showed that the mechanical properties are extremely sensible to thermo-mechanical routes applied. Different values for mechanical properties of the sheets can be produced by distinct thermo-mechanical sequences. These combinations make possible a better flexibility in the production process, preserving the compromise between formability and mechanical strength in view of the specifications of each sheet and foils produced from this alloy

ASSUNTO(S)

propriedades alumÃnio engenharia mecanica mecÃnicas

ACESSO AO ARTIGO

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