Cite this document

ASTM Suggested Citation Style, Chicago Manual of Style 17th Edition Publication Manual of the American Psychological Association, 6th Edition MLA Handbook for Writers of Research Papers 7th Edition URL

Near-net shape hot isostatic pressing (HIPping) in powder metallurgy (P/M) has been on the increase in the production of superalloys for aero and land based turbine disc applications. A critical challenge related to net-shape HIPping PM is the presence hafnium rich γ–γ′ eutectic in some superalloys powder, which promotes the formation of hafnium oxide. This encourages the formation of prior particle boundary (PPB) precipitates during HIPping, which decreases the bonding strength between powder particles during HIPping and thus becomes the crack initiation and growth sites under loading. Hence, this study aims at dissolving hafnium rich γ–γ′ eutectic in RR1000 superalloy powder and eliminating the PPB precipitates after HIPping by heat treating the powder prior HIPping. As-received powder was heat treated at 900, 1000, 1100, and 1200°C for 2 h, and their microstructure was characterized before the application of pressure for its consolidation. From the outcome of the study, 1200°C was found to be the optimum heat treatment temperature where hafnium rich γ–γ′ eutectic dissolved and where prior particle boundary (PPB) precipitates were eliminated during HIPping for the RR1000 superalloy powder studied.