Deformation and annealing behavior in the ‘interaction zone’ of cold-rolled tantalum sheets

Abstract

The characteristic of the ‘interaction zone’ in the unidirectional rolled Ta sheets was systematically investigated by X-ray line profile analysis (XLPA), electron backscatter diffraction (EBSD) and transmission electron microscope (TEM). The ‘interaction zone’ consisted of the {111} (<111>//(normal direction (ND)), {100} (<100>//ND) and {100}-R matrix (rotation grain of {100} matrix rotating by <111> axis of the {100} matrix). The microstructure of the ‘interaction zone’ with increasing strains was revealed by misorientation map, kernel average misorientation and grain reference orientation deviation-hyper. The occurrence of the ‘interaction zone’ can be mainly attributed to the large difference of stored energy and the local stress between the {111} and {100} matrix, and the {100}-R matrix seemed to provide strain accommodation between the metastable {111} and stable {100} matrix. Schmid factor analysis indicated that the deformation behavior within the ‘interaction zone’ showed strong orientation dependence. Therefore, the difference in the stored energy and the fragmentation of microstructure led to a heterogeneous driving force and preferred nucleation sites in the ‘interaction zone’, resulting in subsequent different recrystallization kinetics when sample annealed at 1050 °C under vacuum condition.