Analysis of sharp microtexture heterogeneities in a bimodal IMI 834 billet

Regions with sharp hexagonal close-packed (hcp) local textures, named macrozones, have been observed in an IMI 834 billet and analyzed in relation to the bimodal alloy microstructure. They are clearly related to regions with primary alpha(p) grains oriented around a main texture component. The resulting alpha(p) microtexture is discussed considering heterogeneous deformation and globularization of initial packets of alpha(p) lamellae. Within an hcp macrozone, several prior beta grain orientations were present at high temperature. The beta phase developed no sharp texture heterogeneities during alpha/beta working. Clusters of beta grains sharing close orientations and containing small grains with high angle boundaries were observed. This beta microtexture can result from severe alpha/beta deformation of initially large prior grains, associated with continuous dynamic recrystallization. By cooling, the alpha(s) colonies inherited from the beta grains and surrounding the ap grains display several texture components with the main one matching that of the alpha(p) phase. This connection seems to be due to a variant selection influenced by the presence of ap grains. (c) 2005 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.