Figure 6: Microstructure evolution for the aged Fe₇₃Ga₂₇.

In situ TEM characterizations at (a,b) 298, (c,d) 473, (e,f) 573 and (g,h) 673 K, respectively. All bright-field images are taken by tilting grain 1 (dashed red circle region) with the [112]_fcc zone axis, the SAED pattern taken at 298 K is shown in (b). (d, f, h) are enlarged views of the red rectangles in (c,e,g), respectively, where the interface between transformed (indicated by fcc) and untransformed (indicated by bcc) regions in grain 2 is indicated by dashed white line, showing that the volume fraction of fcc phase increases upon heating. Scale bars, 500 nm (a,c,e,g); 100 nm (d,f,h).