Verification of selective laser melting heat source models with operando X-ray diffraction data

The output obtained from operando X-ray diffraction experiments on Ti-6Al-4V is used to verify the accuracy of four FEM models in predicting the temperature evolution of the solidified domain, the cooling rates of the alpha and beta phases, and the influence of the scanning vector length on the duration of the beta phase. Three different laser heat sources are considered: a simple ellipsoid, a double ellipsoid, and a cylindrical source with a parabolic penetration curve. The comparison between simulated and experimental results allows to verify the role of radiation loss and symmetric/asymmetric enhanced thermal conductivity on the cooling evolution. Furthermore, it is shown that the evolution of the lattice strains evidence the formation of residual stresses and can be used for the further development of phase field and thermomechanical inspired FEM-based models.