Electrical Resistivity Study of the Phase Separation in Fe–Cr Alloys at 773 K

The electrical resistivity (ER) method was applied to study decomposition of a solid solution in four Fe–Cr alloys Cr9, Cr11, Cr16, and Cr22 during aging at 773 K. Additionally, the similar ER data obtained on decomposition of Cr27 at 773 K and available elsewhere were taken into consideration. The obtained results divided the alloys into 3 groups: (1) Cr9; (2) Cr11 and Cr16; and (3) Cr22 and Cr27. The ER of Cr9 remained unchanged. Within the second or third group, the characteristic features of ER variations are the same, but change significantly with the transition from one group to another. The change is associated with a change in the mechanism of decomposition from that with the formation of nuclei to spinodal one. Estimate of the boundary concentration between concentration regions of these two mechanisms at 773 K is made.