“…Traditional Fe-Cr-Al alloys targeted for high-temperature oxidizing environments, such as PM2000™ or APMT™, use high (i.e., >15 wt %) chromium solute additions, which have been known to exhibit phase instability in typical LWR clad operating temperatures [9,[17][18][19][20][21][22][23][24][25]. This phase instability is the result of the miscibility gap in the body-centered-cubic (BCC) Fe-Cr system [26][27][28] and has been indicated to exist within the BCC Fe-Cr-Al ternary system as well [9,[17][18][19][20][21][22][23][24][25]. High-chromium-content Fe-Cr and Fe-Cr-Al decomposes into the Fe-rich α and Cr-rich α' phases.…”