Uncovering Grain Boundary Metastability as a Response to Radiation in FCC and BCC Single Phase Compositionally Complex Alloys

Compositionally complex alloys (CCAs) are promising for the future materials of extreme radiation environments, but nuances in unique defect formation and evolution properties have yet to be thoroughly understood. In comparison to their dilute and pure counterparts, both fcc and bcc complex alloys retain local chemical order which increases the radiation tolerance due to a convoluted matrix defect bias. This bias profoundly influences grain boundary (GB) metastability under irradiation conditions, resulting in an increase in radiation tolerance with alloy complexity. A combined molecular dynamics and experimental in-situ study is preformed to demonstrate GB metastability during point defect bombardment, highlighting the fundamental differences between fcc and bcc alloys, in addition to environments with and without local chemical order.