(S2·17-S042)Creep Strengthening Mechanism by Using Grain Boundary Laves Phase in Fe-20Cr-30Ni-2Nb Austenitic Heat Resistant Steel

摘要

The advanced ultra supercritical (A-USC) power plants require wrought materials with creep rupture life of 105 h at 973 K under 100 MPa. For this application, we have proposed a new austenitic heat resistant steel Fe-20Cr-30Ni-2Nb (at.%) strengthened mainly by intermetallics Fe2Nb-Laves phase at grain boundaries. The creep rupture strength of this steel is much superior to the conventional austenitic heat resistant steels strengthened by metallic carbides and nearly reaches the requirement for the A-USC. In this study, we have examined the role of grain boundary (GB) Laves phase in creep strength.