Considering that the double differentiation technique involves purely mathematical findings, microstructural analysis is needed to validate the presence of dynamically transformed ferrite, as presented below.

Fig. 5 a show the grain boundary map of the specimen after double hit deformation at 1150 °C and a strain rate of 0.25 s^-1. A detailed observation of the microstructures shows a morphology composed of laths and few quasi-polygonal grains (indicated with red arrows). The plates observed in the microstructure appear to have Widmanstätten type morphology, which originates from the interior of the prior austenite grains. This observation is consistent with the results of numerous researchers [1, 16, 17] who linked their formation to the applied stress, which stimulates the displacive transformation of austenite to Widmanstätten ferrite.

EBSD grain boundary maps, reported in Fig. 5 (a) shows that a significant amount of low-angle grain boundaries is present in the microstructure. This indicates that the microstructure is not fully recovered after the second hit. However, the presence of any LAGBS was not found in the laths and plates, which suggests that these grains underwent recrystallization and phase transformation.