Construction of a Thermodynamic Database for Ni-Base Superalloys: A Case Study
Ursula R. Kattner
Ni-base alloys are the most widely used superalloys in applications involving high temperatures and severe environmental conditions. To model the various processing steps used for these alloys, improvements in thermodynamic databases are required. These databases are also necessary to describe the thermodynamic factor for diffusion database development. The first thermodynamic database for superalloys was developed by Larry Kaufman and co-workers in the 1970's. Since then, computational technology has constantly improved, resulting in advanced model descriptions and better agreement observations. A database for Ni-base superalloys with emphasis on single crystal alloys has been assembled for 10 components: Ni, Al, Co, Cr, Hf, Mo, Re, Ta, Ti, W. Since the number of subsystems for such a database is enormous, many assessments from the literature were used. These assessments were reviewed for consistency and, as necessary, partially remodeled. Experience from assembling this database and a discussion of a more systematic estimation procedures for the unknown quantities will be presented.