Investigation on composition distribution of dissimilar laser cladding process using a three-phase model

Abstract

During the laser cladding process, complex transport phenomena occur in the molten pool including strong convection, substrate melting, melt solidification, species transport, etc., which determine the final distribution of solute concentration in the cladding layer. In this study, a three-phase Eulerian volume averaging approach was developed to investigate laser cladding with 316L steel powder on 45 steel substrate. The numerical results were validated by experimental results in terms of the geometrical morphology and chromium concentration of the cladding layer. The numerical results indicate that two distinct vortexes, driven by Marangoni force, lead to two mixing stages, i.e., the premixing stage in the front of the molten pool and the fully mixing stage in the rear of the molten pool. Both of the two mixing stages have significant effects on the final distribution of compositions in the cladding layer. Meanwhile, due to the inadequate mixing of all the compositions in the molten pool, heterogeneous composition distribution of chromium was observed both in the experimental and simulated results.