(S239)Effect of V on the Precipitation of Fe2Nb (TCP) and Ni3Nb (GCP) Phases in Novel Fe-Cr-Ni-Nb Austenitic Heat Resistant Steels

摘要

In novel Fe-Cr-Ni-Nb austenitic steels at elevated temperatures, we demonstrated the decorating grain boundaries (GBs) with Fe2Nb Laves phase improves the long-term creep rupture strength with gmma"-Ni3Nb phase in grain interiors (GIs) for the short-term creep strengthening. Since both intermetallics compete on the common Nb supersaturation for their formation, precipitation control of each phase is difficult to increase the GB area fraction of Laves phase. In this study, we discuss the effect of additional transition element of vanadium to control the precipitation of the Fe2Nb and Ni3Nb phases.