Rapidly solidified nickel-base superalloys

• Published in: Journal of materials science 1980-11, Vol.15 (11), p.2709-2719
• Main Authors: Wood, J V, Mills, P F, Waugh, A R, Bee, J V
• Format: Article
• Language: English
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/BF00550537

The structures of rapidly solidified APK1, IN-100 and low-carbon IN-792 are described and compared with that of Nimonic 80A. Under identical processing conditions, cellular, dendritic and homogeneous equiaxed structures can be obtained. This is not due to either the influence of cooling conditions or to any single alloying addition, but depends on the combined effects of the Ti, Cr and C contents. The spinodal-type formation of gamma ', proposed for Nimonic 80A, cannot be suppressed in these alloys by pendant drop melt extraction or melt spinning techniques. However, detailed atom-probe field-ion microscopy suggests that the gamma ' formation in APK1 does develop by a similar mechanism. Although not directly attributable to a modulated microstructure or to the presence of disordered particles, the extremely high strength levels observed in this alloy after heat treatment are due to the subsequent development of small, ordered, gamma ' precipitates in a fine-grained matrix, together with the absence of deleterious grain boundary carbide precipitation.19 refs.--AA