Substructure development in hot plane strain compressed Al-1%Mn crystals

Hot PSC (channel-die) tests have been carried out to large strains (1.5) on 3 orientations of AI-1%Mn crystals, Bs{110} <112>, S {123} <412> and U {110} <1 $(1) over bar 0 >, using a wide range of temperatures and strain rates (or Zener-Hollomon parameter Z). The deformation substructures are characterised by EBSD orientation mapping in terms of sub-grain sizes 3 and sub-grain misorientations and their frequency distributions over large areas. The sub-grain sizes respect the linear relation between 1/delta and InZ but with significant orientation dependency. The largest sub-grains are found in the Bs orientation at all Z and the smallest in the S orientation at high strain rates. Sub-grain misorientations increase rapidly with strain to 3 or 4degrees then approximately stabilise after 0.5 or 1. Some high angle boundaries (> 10degrees) are formed with frequencies about 10(-2) to 10(-3). Many of the size effects can be attributed to an enhanced rate of sub-boundary generation in the case of the unstable grain orientations. (C) 2003 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.