Anomalous particles (granules) in PREP-powders. A multiscale study of the PREP- powders and PM HIP compacts of the Ni-based superalloys and stainless steels

摘要

Formation of the anomalous particles (granules) with the essentially different content of the microalloy-ing interstitial elements carbon and boron is characterized for the composition uniformity of the rapidly quenched powder particles of the high temperature Ni-based superalloys and stainless steels pro-duced by PREP-technique. A detailed multiscale experimental study of microstructure of the PREP-powders and PM HIP compacts of the Ni-based superalloys and stainless steels was performed with the aim to reveal the microstructure features of the anomalous granules in the as-received and consol-idated state. The direct nuclear methods of activation autoradiography on carbon, track autoradiog-raphy on boron, metallography, SEM, EDX, and OIM were used. The essential effect of carbon and boron on the dendrite segregation of carbide- and boride-forming alloying elements in the anomalous granules was revealed. Features of carbon and boron behavior determine formation of the microstruc-ture of anomalous granules and their retaining in PM HIP compacts were established.