Phase field modeling of solidification in multi-component alloys with a case study on the Inconel 718 alloy

We develop a phase field model for the simulation of chemical diffusion-limited solidification in complex metallic alloys. The required thermodynamic and kinetic input information is obtained from CALPHAD calculations using the commercial software-package ThermoCalc. Within the case study on the nickel-base superalloy Inconel 718, we perform simulations of solidification with the explicit consideration of 6 different chemical elements. The stationary dendritic tip velocities as functions of the constant undercooling temperature obtained from isothermal solidification are compared with the stationary tip temperatures as functions of the imposed pulling velocity obtained during directional solidification. We obtain a good quantitative agreement between the two different velocityundercooling functions. This indicates that the model provides a self consistent description of the solidification. Finally, the simulation results are discussed in light of experimental solidification conditions found in single crystalline casting experiments of Inconel 718.