Electron tomographic observation of precipitates on lath boundaries in 10Cr ferritic steel bearing V

Mitsuhara, Masatoshi*; Ikeda, Kenichi*; Hata, Satoshi*; Nakashima, Hideharu*; Wakai, Takashi 

High Cr ferritic steels bearing V have high creep strength due to the precipitation hardening. In order to enhance the efficiency of the precipitation hardening, the elemental components, shape and distribution of the precipitates should be comprehended. In this study, we investigated that of the precipitates in the 10Cr ferritic steel bearing V using the STEM-EDS analysis and the three-dimensional electron tomography (3D-ET) observation. The two types of precipitates on the lath boundaries could be observed, which were lump-shaped precipitates and film-shaped precipitates. They had the different elemental component. From the 3D-ET observation, it revealed that the film-shaped precipitates covered the lath boundary widely. Therefore, the film-shaped precipitates are expected to be effective for the stabilization of martensitic microstructure during the creep deformation.