  The mechanism of the evolution of the deformed microstructure at the earliest
stage of annealing where the existence of the lowest length scale substructure
paves the way to the formation of the so-called subgrains, has been studied for
the first time. The study has been performed at high temperature on heavily
deformed Ti-modified austenitic stainless steel using X-ray diffraction
technique. Significant changes were observed in the values of the domain size,
both with time and temperature. Two different types of mechanism have been
proposed to be involved during the microstructural evolution at the earliest
stages of annealing. The nature of the growth of domains with time at different
temperatures has been modelled using these mechanisms. High-resolution
transmission electron microscopy has been used to view the microstructure of
the deformed and annealed sample and the results have been corroborated
successfully with those found from the X-ray diffraction techniques.
