On the plasticity of a hot-rolled Zircolay-4 via a combination of in-situ acoustic emission and ex-situ EBSD techniques

Abstract

The plastic anisotropy of a hot-rolled Zircaloy-4 (Zr-1.56Sn-0.22Fe-0.11Cr) occurring during compressive loading in three orthogonal directions was analysed using the acoustic emission (AE) technique and scanning electron microscopy (SEM). In particular, AE was used for in-situ monitoring of the activity of individual deformation mechanisms. The microstructure was characterized by the electron backscatter diffraction (EBSD) technique in the initial state and after deformation of 2% and 12%, respectively. The grain reference orientation deviation (GROD) maps estimated from the EBSD data reveal the evolution of slip system activities in individual grains. During compressive loading along the rolling and transverse directions (RD and TD, respectively), dislocation glide and twinning are dominant deformation mechanisms. Moreover, the AE technique in combination with EBSD analysis indicates that more intensive twinning in RD, reflected by a high twin volume fraction, is rather given by twin thickening than massive twin nucleation. With respect to the initial texture, the twinning is almost suppressed during loading along the normal direction (ND) and plastic deformation is realized by several slip systems, including multiple slip.