The Role of Deformation Banding in Grain Refinement under ECAP

Abstract:

The mechanism of grain refinement in an Al-5.4Mg-0.4Mn-0.2Sc-0.09Zr alloy subjected to equal-channel angular pressing (ECAP) at 300°C through route B_C is considered. It was shown that the formation of geometrically necessary boundaries (GNB) aligned with a {111} plane at ε≤1 initiates the occurrence of continuous dynamic recrystallization (CDRX). Upon further strain the GNBs transform to low-to-moderate angle planar boundaries that produces lamellar structure. In the strain interval 2-4, 3D arrays of planar boundaries evolve due to inducing the formation of 2^nd order and higher orders families of GNBs in new {111} planes. GNBs gradually convert to high-angle boundaries (HAB) with strain. A uniform recrystallized structure is produced at a true strain of ∼8. The role of slip concentration and shearing patterns in the formation of GNBs is discussed.

• Periodical: Materials Science Forum (Volumes 783-786)
• Pages: 2641-2646
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.783-786.2641
• Online since: May 2014
• Authors: Rustam Kaibyshev*, Sergey Malopheyev, Vladislav Kulitskiy, Marat Gazizov
• Keywords: Aluminium Alloy, Dislocation Structures, Equal-Channel Angular Pressing (ECAP), Grain Boundary, Recrystallization

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