For strain reversal deformation, it can be observed from Fig. 4 (b) that average grain size at the edge continuously decreases from ԑ=1 to ԑ=60. However, the average grain size at the centre increases at ԑ=60, which is very surprising. Moreover, HAGBs fraction (Fig. 4(a)) increases from 21% at ԑ=1 to 82% at ԑ=4, thereafter no significant change is observed at the edge. It can be noted that the HAGBs fraction of strain reversal deformation at the edge region is less than the HAGBs fraction of monotonic deformation at nearly all strain levels.