Multiphysical modeling of dissimilar welding via interlayer

A multiphysical finite element modeling of dissimilar welding via interlayer material was proposed. A 2D model including heat transfer, fluid flow and level set problems allowed to simulate the morphology and the composition of melted zone in horizontal plane. The calculated thickness of melted interlayer was used as a main criterion for the choice of optimal welding conditions, when the chemical interaction between the joined materials must be avoided. A 1D diffusion model at the limit of melted zone allowed estimating the length and the composition of diffusion layer between one of the materials and the interlayer basing on previously calculated local temperature gradient. The simulations were carried out in finite element software COMSOL Multiphysics.The application of the models to dissimilar TA6V to stainless steel AISI 316L electron beam joining via copper interlayer allowed to study the effect of different welding conditions (beam offset and welding speed) on the mixing between three involved materials and thus to determine the favorable operational conditions basing on the properties of dissimilar system and to give the first approach of heterogeneous interface description. The comparison of modeling results with an experiment confirmed the presence of very narrow region of optimal conditions, which is in good correspondence with simulation.

► This study is dedicated to numerical modeling of dissimilar welding via interlayer.
► The models have been applied to Ti6Al4V–copper-316L steel electron beam welding.
► The first model includes heat transfer, fluid flow and level set problems.
► The second model describes local Ti diffusion at melted zone interface.
► The present study has allowed determination of optimal welding parameters.