Effect of boron on the grain boundary morphology and creep property in nickel-based superalloy LESS 1

摘要

To examine the correlation between microstructure and creep property by addition of boron, effect of boron on the grain boundary morphology and creep resistance in nickel-based superalloy LESS 1 is investigated. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and small-punch creep test are carried out. In case of boron-added LESS 1, so-called boro-carbides (M_(23)(C, B)_6) and γ' film (Ni_3(Al, Ti)) are precipitated at grain boundary (GB). Also creep resistance is considerably increased by addition of boron. The improvement of creep resistance can be attributed to the change of grain boundary morphology by addition of boron.