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. (C) 2016 Elsevier Ltd. All rights reserved.