Secondary precipitation within the cementite phase of reactor pressure vessel steels

Solute clustering is known to play a significant role in the embrittlement of reactor pressure vessel (RPV) steels. In this study, previously unobserved manganese-, nickel-, and silicon-rich precipitates in the cementite phase of a thermally aged, low copper RPV steel are characterised at the atomic scale via atom probe tomography. Additionally, copper-rich precipitates are observed in the cementite phase of a thermally aged, high copper RPV steel. Due to their secluded nature, these secondary precipitates could be utilised as indicators of the time–temperature exposure of RPVs and assist in assessing remnant lifetime. [Display omitted]