Dissimilar material lap joints by Friction Stir Welding of Steel and Titanium Sheets: Process Modeling

摘要

In the paper a continuum based FEM model for Friction Stir Welding of different material lap joint made out of thin stainless steel and titanium sheets is proposed. The simulation campaign was made out using the 3D Lagrangian implicit code DEFORM by means of a rigid-visco-plastic approach. The model, already set up and tuned for FSW process of similar materials and geometrical configurations takes into account the different mechanical and thermal behavior of the two materials and the microstructural evolution of the considered titanium alloy in the same joint. Additionally, it is able to predict temperature, phase, strain and strain rate distributions and evolution at the varying of the main process variables. The phase evolution models take into account only the main phases called Alpha, Beta and Alpha+Baeta so that, at the end of the simulation, the complete phase distribution in the welded zone.