Laser Powder Bed Fusion (L-PBF) is seen as a process of interest by aeronautic industry to develop new engine components. Nevertheless, the reliability and durability of parts produced by L-PBF depends on the possibility to suppress the occurrence of defects. Among them, hot cracking represents a key issue. These cracks are due to the liquid film remaining between grains at the end of the solidification stage combined with stresses and strains endured by the mushy domain. A microsegregation model providing relevant prediction of the solidification path during L-PBF is thus required for coupling with a thermomechanical analysis. As an answer to the industrial need, a new model is proposed and applied in cooling conditions encountered in L-PBF. It includes the initial solidification conditions and follows the solid fraction evolution and species composition in the interdendritic liquid region to predict the brittle temperature range. Both dendrite tip growth model and kinetic phase diagram due to non-equilibrium interface phenomena are considered. Cross-diffusion of solute species in the liquid phase is accounted for, as well as thermodynamic coupling with CALPHAD. Results are compared to experimental data in the Ag-Cu system before applications dedicated to nickel-base superalloys.

Moderated by: Daan Maijer / Michel Billet