Sequence of inverse FFT images of the area (dashed yellow box) in a showing the nucleation (t - t0 = 12–73 s) and growth (t - t0 = 167 s) of the B2 phase (Supplementary Movie 6). (see Supplementary Fig. 9a for the unprocessed TEM images). The fcc, B2, and interface regions are false-colored in red, blue, and orange, respectively. Note that the nucleation of the B2 phase starts with the formation of an interface region, which acts as a precursor phase for the nucleation. The dashed white lines are guides showing the gradual bending of (002)fcc planes into (101)B2 planes as the B2 phase nucleates and grows. The dashed red lines are the (002)fcc planes. t0 is the timepoint at which we started increasing the temperature from 350 to 500 C at a rate of 1 C s-1.
