Characterisation of interfacial segregation to Cu-enriched precipitates in two thermally aged reactor pressure vessel steel welds

摘要

To understand the contribution of long term thermal ageing to Reactor Pressure Vessel (RPV) embrit-tlement two high Cu steel welds with different Ni contents were thermally aged for times up to 100,000 h at 330 degrees C and 365 degrees C. Microstructural characterisation using Atom Probe Tomography was performed. Thermal ageing produced a high number density of nano-scale Cu-enriched precipitates. The precipitate-matrix interfaces were enriched in Ni, Mn and Si. The characterisation of these interfaces using a double cluster search approach is the subject of this work.