Simulation of solidification and heat treatment of nickel-base superalloy SC16

Thermodynamic equilibrium and Gulliver-Scheil as well as diffusion calculations using the DICTRA program have been made to simulate solidification and heat treatment of the nickel-base superalloy SC16. These simulations were validated by comparing them with own and literature experiments concerning directional solidification, heat treatment and differential thermal analysis (DTA) cycles. Equilibrium calculations predicted very well the element distribution in homogenized samples. Gulliver-Scheil based on the CALPHAD method and modified to serve multi-component systems proved to deliver sufficiently correct data for the directional solidification of SC16. The element distribution obtained after cooling below the solvus temperature and by DTA heating and cooling cycles was, however, only described with acceptable precision by applying the diffusion model. All these models require a sound multicomponent thermodynamic data set. Since DICTRA needs much more computing time than the other models it should only be applied wherever its higher precision is actually asked for.