Surface characteristics of rapidly solidified nickel-based superalloy pow-ders prepared by PREP

摘要

The surface microstructure and the surface segregation of FGH95 nickel-based superalloy powders prepared through plasma rotating electrode processing (PREP) have been investigated by using SEM and AES. The results indicate that the surface microstructure of powders changes fiom dendrite into cellular structure as the particle size of powders decrease, and the predominant precipitates solidified on the particle surfaces were identified as MC' type carbides enriched with Nb and Ti. It was also indicated that along with the depth of particle surfaces, the segregation layer of S, C and O elements are thick, and that of Ti, Cr elements are thin for large size powders while they are in reverse for median size particles.