Influence of strain on precipitation reactions during creep of an advanced 9% chromium steel Original Research Article

Creep tested samples of the 9% chromium steel P92 were investigated using energy filtered transmission electron microscopy (EFTEM) and atom probe field ion microscopy (APFIM). The mean size and the volume fraction of precipitates of type M23C6, VN and Laves phase as a function of creep time and temperature were determined. A comparison with isothermally aged material showed that coarsening of M23C6 carbides is accelerated by the strain, while the effect of strain on VN precipitates is insignificant. It was also found that the number density of Laves phase particles is higher in creep tested material compared to isothermally aged material. Possible mechanisms to explain these observations are discussed.