Microtexture tracking of sub-boundary evolution during hot deformation of aluminium

The microstructure and microtexture evolution of the same 3 grains around a triple point has been followed during hot plane strain compression by electron backscattered diffraction (EBSD) up to a strain of 1.2. A large grained model alloy of Al–0.1 wt% Mn was deformed in the form of a split sample in channel die compression at 400 °C by 3 repeated cycles, each involving EBSD grain orientation mapping, hot deformation and quenching. Detailed substructure maps of 3 grains on an inner surface demonstrates that their dislocation substructure develops up to a strain of about 0.5 then stabilises at approximately constant size, disorientation distribution and boundary alignment. The results are consistent with the repolygonisation model of steady state sub-boundary creation and dissolution during hot deformation.

► Same area around triple point in Al followed by EBSD during hot deformation. ► Strains from 0 to 1.2 by intervals of about 0.4. ► Sub-grain microstructure and microtexture stabilise after strains of about 0.5. ► Results consistent with model of continuous creation and dissolution of sub-grains.