About the activation volume for cross-slip in Cu at high stresses

The experiment performed by Bonneville and Escaig, designed for the direct measurement of the activation parameters of cross-slip, has been repeated. A denser initial dislocation forest density is obtained with a higher predeformation stress compared with a previous study. The minimum activation volume at yield is 124b(3) when cross-slip is dominant at 24 K, instead of 280b(3) as proposed formerly. Consequently, the activation energy at zero stress is in the range of 0.61 eV, lower than in the previous study. The results are discussed in terms of predictions of linear elasticity models and those from recent atomistic simulations. To understand the discrepancies between the experimental and simulation results the Bonneville Escaig method, as well as the simulation conditions, require further assessment. (C) 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.