Phase-field modeling of pores morphology in Compositionally-Graded Complex Alloys, validated by experiments

A. Riyahi khorasgani*, J. Kundin*, I. Steinbach*, B. Camin**

*ICAMS, Ruhr-Universität Bochum, Germany, ** TU-Bremenhafen, Germany

A novel methodology is proposed for the simulation of pores/voids  evolution in multi-component graded complex alloys, based on the phase-field modelling. The technique combines the continuum description of vacancy formation/annihilation [1] aligned with the thermodynamic/kinetic CALPHAD databases and the phase-field approach in order to model the porosity growth.

The calculation of multi-component diffusion and the pores formation on the same time and space scale enable us to accelerate the simulations. Moreover, the included cubic anisotropy allows to reproduce the various shapes of pores e.g. dendrite, pyramids and cups.

The pore morphologies, coupled with concentration gradient, are simulated for the cases of Ni-based super alloys and HEA alloys; the simulations can be consistently compared with the X-ray tomography results at micrometer and sub-micrometer scales. All simulations are prepared using OpenPhase software with parallel codes in 2D and 3D.  

[1] C.-H. Xia, J. Kundin, I. Steinbach, S. V. Divinski. Model for non-equilibrium vacancy diffusion applied to study the Kirkendall effect in high-entropy alloys, Acta Materialia, 232, 117966, (2022)