The modeling of dissimilar welding of immiscible materials by using a phase field method

A multiphysical model of high power beam welding of immiscible materials is developed to explain the influence of operational parameters and materials properties on resulting morphology by simultaneous solving of heat transfer, fluid flow and mass transfer problems. The introduction of phase field description of the interface motion between two immiscible liquids allows obtaining the cartography of melted zone in function of two key-parameters: the position of heat source relatively to joint line and the welding speed.Due to the short thermal cycle limiting mass transfer, high power beam welding techniques may result in very inhomogeneous melted zones. In this study, the interest is paid to copper to stainless steel Nd:YAG laser and electron beam joints, which often present the repetitive heterogeneous patterns. The modeling results are validated by the comparison with experimental data on weld shape, composition and morphology.