Study of the Microtexture of Recrystallized Aluminium

Abstract.

The nucleation of recrystallized grains in deformed, high-purity aluminium were examined in relation to the microstructural heterogeneities in the form of shear bands (SBs) and transition bands (TBs). The experiments were carried out on single crystals deformed in channel-die compression at 77 K to true strains within the range of 1–1.5. The substructures were identified by means of a combination of transmission (TEM) and scanning (SEM) electron microscopes. Local texture measurements in particular places of samples were mostly investigated by means of TEM and convergent beam electron diffraction (CBED), with on-line diffraction pattern analysis. The coarser analyses were performed by SEM and electron back scattered diffraction (EBSD). The \({\rm C}\{112\} \langle 111 \rangle\) and the \({\rm S} \{531\} \langle 123 \rangle\) oriented single crystals are stable in the global sense and form clearly defined SBs. The \({\rm H} \{110\} \langle 110 \rangle\), and the ‘shear’ \(\{100\} \langle 011 \rangle\) orientations are very unstable and tend to form TBs. The nuclei of new grains formed along the band are misoriented by α (\(\langle 111 \rangle or \langle 112 \rangle\)) with respect to the orientations identified within the neighbouring banded material. The author attempts to explain, from the crystallographic point of view, the processes operating within high stacking fault energy metals at the very early stages of recrystallization.