Damage in nickel base superalloy: Influence of local parameters measured by electron backscattered diffraction and atomic force microscopy

The low-cycle fatigue behaviour of a nickle-based superalloy has been investigated with regard to its surface damage features. This alloy endures localized plastic deformation confined in slip bands emerging as extrustions. The correlations between damage, grain orientation, the Schmid factor of slip systems and the height of extrusions have been questioned. It is proved here that reaching a critical height value is not a sufficient condition for an extrusion to induce the apparition of a transgranular crack. (C) 2008 Published by Elsevier Ltd. on behalf of Acta Materialia Inc.