Carbon–vacancy interaction controls lattice damage recovery in iron

Ab initio techniques are applied to assess the positron lifetime of carbon–vacancy (C–V) complexes in iron for the first time. Positron lifetime is extremely sensitive to C–V arrangement and multiplicity. Following the ab initio lifetime data, a C–V complex can be detected as a single or clustered vacancy, or remain indistinguishable from bulk. Combining ab initio data with kinetic rate theory, we modelled annealing of irradiated Fe–C alloys and performed one-to-one comparison with experiment, which revealed a good agreement.