A novel computational model for isotropic interfacial energies in multicomponent alloys and its coupling with phase-field model with finite interface dissipation

Abstract

• A CALPHAD model for isotropic interfacial energies was developed and programmed. • Direct coupling between interfacial energy model and phase-field model was realized. • Isotropic interfacial energy databases in Ni-Al-Cr systems were established. • 3-D phase-field simulations of γ dendritic growth in two Ni alloys were conducted. • Effect of different interfacial energies on γ dendritic growth was analyzed. In this work, a novel computational model for the description of the temperature- and composition-dependent isotropic interfacial energy in multicomponent alloys was first developed in the framework of the CALculation of PHAse Diagram (CALPHAD) approach and implemented in a home-made code. By linking to the open-source code for interfacial energy calculation in alloys, OpenIEC, the databases for isotropic γ /liquid and γ / γ' interfacial energies in Ni-Al, Ni-Cr, Al-Cr, and Ni-Al-Cr systems were then efficiently established. After that, a direct coupling strategy between the current CALPHAD interfacial energy database and the phase-field model with finite interface dissipation was proposed and applied to three-dimensional (3-D) phase-field simulations of the primary γ dendritic growth in both Ni-Al and Ni-Al-Cr alloys during isothermal solidification. The effect of the interfacial energy on the morphology, tip growth rate, and partitioning coefficients in primary γ dendrites of binary Ni-Al and ternary Ni-Al-Cr alloys was investigated by comprehensively comparing the phase-filed simulation results using the composition-/temperature-dependent interfacial energies with those using the constant value. It is anticipated that the presently developed CALPHAD model for interfacial energy is of general validity for different multicomponent alloys and should be integrated with the phase-field model for quantitative simulation of their microstructure evolution.