Internal Stress Field in Ultrafine Grained Aluminium Fabricated by Accumulative Roll-Bonding

Abstract:

Internal stress field in a severely deformed aluminium with ultrafine grained microstructure has been studied by convergent-beam electron diffraction (CBED) technique in transmission electron microscopy (TEM). A commercial purity aluminium (99.1%Al) sheet was highly strained by the accumulative roll-bonding (ARB) process to evolve an ultrafine grained structure. Higher-order Laue zone (HOLZ) lines in the incidence disk of the ] 12 1 [ zone axis have been observed at various positions within an identical ultrafine grain. The key finding is that the HOLZ line pattern taken from the vicinity (~50nm) of the grain boundary (lamellar boundary) looses ) 1 1 0 ( mirror symmetry, whereas the pattern from the grain centre has the symmetry. The former and the latter represent the existence of a large non-hydrostatic stress field and a small internal stress field, respectively. The magnitude of the internal stress becomes larger with approaching to a grain boundary.

• Periodical: Materials Science Forum (Volume 512)
• Pages: 123-128
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.512.123
• Online since: April 2006
• Authors: Rintaro Ueji, J. Taniguchi, N. Sumida, Katsushi Tanaka, Nobuhiro Tsuji
• Keywords: Accumulative Roll Bonding (ARB), Aluminum (Al), Convergent Beam Electron Diffraction (CBED), Internal Stress, Severe Plastic Deformation (SPD), Ultrafine Grained

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