Dislocation densities in soft and hard oriented grains of compression deformed textured NiAl polycrystals

Abstract

Abstract NiAl polycrystals with different textures have been compressed at room temperature with and without confining pressure to strains of 6 and 30 %, respectively. Grain orientation dependent dislocation densities have been determined by X-ray line profile analysis using the multiple whole profile procedure. The dislocation density as well as the stored energy in hard grains, <100> oriented with respect to the compression axis, generally is about half of that in soft grains, which are randomly oriented. Taking into account appropriate individual dislocation contrast factors it has been found that in hard grains slip mainly takes place by <111> screw dislocations while in soft grains there is about a 50 % contribution of mixed type <100> dislocations. The results are discussed with respect to the inhomogeneity of deformation of plastically anisotropic materials and its effect on recrystallization.