Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1575076 | Materials Science and Engineering: A | 2014 | 9 Pages |
Abstract
The 7075 Al alloy was severely deformed at 350 °C by a 3:1 thickness reduction per pass accumulative roll bonding (ARB) process up to six passes. It was found that discontinuous recrystallisation occurs during the inter-pass annealing stages from the third pass on, attributable to the increment of the mean particle size during processing. As a consequence, the mean crystallite size did not decrease, but remained approximately constant at 440 nm along the present ARB process and the mean boundary misorientation angle reached a maximum of 30° for the 3-passes sample. However, since nucleation of new grains takes place at the pre-existing grain boundaries, discontinuous recrystallisation results in slight changes in texture throughout the processing, being the orientations in the ARBed samples predominantly located along the typical rolling β-fibre. Uniaxial tests conducted at 300 °C and 350 °C revealed that the operating deformation mechanism in the processed alloy at such temperatures was grain boundary sliding; the optimum superplastic strain rate being 3Ã10â3-10â2 sâ1. Boundary misorientation and thermal stability are the two main factors that contribute to high elongations to failure.
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Physical Sciences and Engineering
Materials Science
Materials Science (General)
Authors
P. Hidalgo-Manrique, C.M. Cepeda-Jiménez, A. Orozco-Caballero, O.A. Ruano, F. Carreño,