Presence and absence of significant twinning: Effects on cold deformed microstructures of single phase Zircaloy 2

Abstract

Fully recrystallized Zircaloy 2 samples were made in two dominant classes of crystallographic orientations: grains with predominantly (I) basal (< 0 0 0 1 >) and (II) non-basal plane-normal. The present study charted out detailed microstructural developments, of both the samples, during uniaxial cold compression. Sample I showed insignificant twinning and had stronger signatures (in-grain misorientation and estimated values of lattice strain and dislocation densities) for slip; while sample II had both slip and twin and substantial modifications in crystallographic texture. Strong heterogeneity in residual stress was observed between the suspected parent and product grains/orientations of twinning. This effect could be captured, effectively, with a simple geometric model based on anisotropic elastic stiffness. (C) 2009