Characterisation and quantification of cavities in 9Cr martensitic steel for power plants

• DOI: 10.1179/1743284714y.0000000635
• Publication Date: 2014-08-12T13:38:57Z
• Authors: S. D. Yadav; B. Sonderegger; B. Sartory; C. Sommitsch; C. Poletti
• Keywords: Lath; Field emission gun; Field emission microscopy; Volume fraction

This work focuses on the characterisation of cavities evolution in a P91 steel pipe three conditions: as received, and after creep at 650°C 60 MPa for 7000 9000 h. A field emission gun scanning electron microscope (FEG-SEM) equipped with focused ion beam (FIB) gun, conventional (SEM) light optical (LOM) have been employed investigation. study reveals two types cavities: pre-existing cavities, which are rare this type heat resistant steels, mean diameter 2·56 μm produced during diameters smaller than 0·6 μm. Lath boundaries precipitates found to be preferential sites cavity nucleation. Furthermore, number density volume fraction these small calculated from 2D measurements compared 3D results obtained by FIB serial sectioning.