Effects of irradiation parameters on ' phase precipitation in FeCrAl alloys

Yamashita, Shinichiro   ; Abe, Yosuke  ; Okubo, Nariaki   ; Ukai, Shigeharu  ; Sasaki, Taisuke*

This study continues our investigation of FeCrAl alloys, promising candidates for accident-tolerant fuel cladding materials, aiming to clarify the precipitation behavior of the embrittlement phase (' phase) and to contribute to the development of a predictive model. In FY2024, the irradiation dose was increased from the previously achieved 0.3 dpa, and data up to 0.64 dpa (partially 1.44 dpa) were obtained. This enabled the development of an ' phase precipitation map using chemical composition, damage rate, and damage dose as parameters. Multiple regression analysis quantitatively demonstrated that a decrease in damage rate, along with increases in Cr concentration and damage dose, tends to increase precipitation volume fraction. Notably, Al addition was found to suppresses ' phase precipitation, providing important insights for alloy design.