The understanding and control of the precipitation of secondary phases during heat treatments is critical for the properties of age-hardening superalloys. A modeling tool has been developed at CompuTherm to simulate the complicated precipitations and microstructure evolutions during arbitrary thermal histories.
The modeling tool, which is part of the Pandat™ software, integrates both thermodynamic calculation and kinetic simulation. Thermodynamic calculation provides driving force of precipitation while thermodynamic and mobility databases are also needed for providing model parameters. The package is designed for generalized applications while in this presentation the investigation is focused on nickel alloys 718 and U720. In this presentation, we will present the general features of this modeling tool and some calculation results for the two nickel alloys. The output results include the amount and size change of each precipitate phase with time, particle size distribution, TTT curves and so on. One unique feature of this modeling tool that offers tremendous help for alloy design is a global optimization module for search of the best or worst scenario given alloy chemistry range and heat treatment conditions. This feature will be discussed in this presentation as well.