Defect behavior and radiation tolerance of MAB phases (MoAlB and Fe2AlB2) with comparison to MAX phases

MAB phases are a new class of layered ternary materials that have already shown a number of outstanding properties. Here, we investigate defect evolution and radiation tolerance of two MAB phases, MoAlB and Fe₂AlB₂, using a combination of experimental characterization and first-principles calculations. We find that Fe₂,AlB₂ is more tolerant to radiation-induced amorphization than MoAlB, both at 150 ℃ and at 300 ℃. The results can be explained by the fact that the Mo Frenkel pair is unstable in MoAlB and as a result, irradiated MoAlB is expected to have a significant concentration of Mo_Al antisites, which are difficult to anneal even at 300 ℃. We find that the tolerance to radiation-induced amorphization of MAB phases is lower than in MAX phases, but it is comparable to that of SiC. However, MAB phases do not show radiation-induced cracking which is observed in MAX phases under the same irradiation conditions. This study suggests that MAB phases might be a promising class of materials for applications that involve radiation.