The solidification metallurgy of Alloy 718 and other Nb-containing superalloys

Conference · Sun Jan 01 04:00:00 EST 1989

DOI:https://doi.org/10.7449/1989/Superalloys_1989_59_68· OSTI ID:6002002

Cieslak, M. J.; Knorovsky, G. A.; Headley, T. J.; Romig, Jr., A. D.

The solidification behavior of Alloy 718 and other Nb-bearing austenitic superalloys has been examined using an integrated analytical approach. All alloys of this type begin solidification with the formation of Nb-lean austenitic dendrites. Interdendritic eutectic-type solidification constituents involving MC-type carbides and a Nb-rich Laves phase occur in these alloys. The ..gamma../Laves eutectic constituent terminates solidification in these alloys. Nb is the dominant element in the evolution of solidification microstructure with C and Si affecting the amounts of ..gamma../MC and ..gamma../Laves constituent observed. Simple solidification models predict reasonably well the amount of eutectic constituent observed. 11 refs., 9 figs., 2 tabs.

• Research Organization: Sandia National Labs., Albuquerque, NM (USA)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 6002002
• Report Number(s): SAND-89-0264C; CONF-890646-1; ON: DE89008196
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360101 -- Metals & Alloys-- Preparation & Fabrication
360102* -- Metals & Alloys-- Structure & Phase Studies
ALLOYS
CARBIDES
CARBON COMPOUNDS
CASTING
CRYSTAL STRUCTURE
CRYSTALS
DENDRITES
ELECTRON MICROSCOPY
EUTECTICS
FABRICATION
IRON ALLOYS
JOINING
LAVES PHASES
MICROSCOPY
MICROSTRUCTURE
NICKEL ALLOYS
NIOBIUM ALLOYS
PHASE TRANSFORMATIONS
SCANNING ELECTRON MICROSCOPY
SOLIDIFICATION
WELDING