Orientation imaging microscopy of ultrafine-grained nickel

Orientation imagining microscopy was used to measure the distributions of grain boundary misorientations in ultrafine-grained nickel processed by high-pressure torsion and equal-channel angular pressing. Both procedures give high fractions of high-angle boundaries but also higher fractions of low-angle boundaries than anticipated from a random distribution. (C) 2002 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.