Estimation of conjugate gamma and gamma-prime compositions in Ni-base superalloysTo control the formation of unwanted phases, superalloy metallurgists have developed methods of estimating the composition of the matrix phase of alloys. That composition is then used to estimate the alloy's propensity toward sigma and other unwanted phase formations upon prolonged exposure to elevated temperatures in service. This paper reviews two approaches for estimating phase composition from the melt composition. One method is based on assigning essentially fixed stoichiometry to precipitating phases and is typified by 'PHACOMP'. The second method uses analytical geometry to interpret phase diagrams and is shown to be applicable to a two-phase region of a six-component Ni-base system. The geometric method is also shown to be applicable to commercial Ni-base superalloys.
Document ID
19770043545
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Dreshfield, R. L. (NASA Lewis Research Center Cleveland, Ohio, United States)
Date Acquired
August 8, 2013
Publication Date
January 1, 1977
Subject Category
Metallic Materials
Meeting Information
Meeting: Workshop on Applications of Phase Diagrams in Metallurgy and Ceramics