From TEM observation, if
DT > DT*, the matrix shows a mixture of typical lathy
martensite morphology and particles without a martensite
feature (see the inserted images in Fig. 1d). X-ray
diffraction (XRD) analyses indicate only the bcc (body
centered cubic) lattice structure dominates in the above
microstructures (not shown here). As it is well known
that only a-ferrite and martensite have bcc structure at
room temperature (RT); it can be inferred that, for
DT > DT*, the matrix and the second-phase particles
should belong to martensite and a-ferrite, respectively.