An improved method to identify grain boundary creep cavitation in 316H austenitic stainless steel

Inter-granular creep cavitation damage has been observed in an ex-service 316H austenitic stainless steel thick section weldment. Focused ion beam cross-section milling combined with ion channelling contrast imaging is used to identify the cavitation damage, which is usually associated with the grain boundary carbide precipitates in this material. The results demonstrate that this technique can identify, in particular, the early stage of grain boundary creep cavitation unambiguously in materials with complex phase constituents.

Research highlights► FIB milling plus ion channelling contrast optimise the observation of cavity. ► Identification of the creep cavities unambiguously, using an FIB technique. ► The FIB technique can retain the polyhedral shape of cavity. ► Various stages of creep cavitation can be observed, using the FIB technique.