On the mechanisms involved in the tensile strength of a dissimilar Ti6Al4V/316L laser welded assembly

The aim of the present work is to analyze the thermomechanical behavior of dissimilar laser seams by means of FE modeling. The case of a Ti6Al4V/316L assembly with vanadium insert was considered. Effective mechanical properties of the main materials and cords were first estimated from NHT measurements. Modeling of the double pass laser welding process was performed first by considering shrinking of the two weld seams during manufacturing, to get the residual stress state in the welded assembly. Modeling of the tensile test was performed in a second step to study the assembly behavior during loading. In these modeling results, the mesh was the cross-section of the micrograph of the assembly itself. The corresponding stress/strain curve was calculated and results were reported for the residual stress state after manufacturing as well as a stress state close to the Ultimate Tensile Strength.