Dissimilar Laser Beam Welding of Titanium to Stainless Steel Using Pure Niobium as Filler Material in Lap Joint Configuration

In the present investigation, commercially pure titanium is welded to AISI 316L stainless steel by intermixing niobium as filler material in a lap joint configuration. For this purpose, a pulsed Nd:YAG laser with various pulse durations and pulse peak powers is employed to obtain different mixing conditions for the materials. It will be demonstrated that, despite the implementation of the filler material, the weld seams are characterized by a high affinity for cracking, which in turn can be attributed to the formation of hard intermetallic compounds. Nevertheless, utilization of optimized process parameters can yield crack-free specimens in a reproducible manner through equable intermixing of otherwise critical alloy elements. Lap-shear forces of up to 140 N can be achieved with a single weld seam measuring 2.5 mm in length. By increasing the joint area with four adjacent weld seams, maximum loads up to 320 N are attained, thus exceeding the yield strength of the applied stainless steel. Considering the biocompatibility of the niobium filler material used, this work provides the foundation for this dissimilar material combination to be implemented in future medical technology applications.

Automated summary

In this study, commercially pure titanium was welded to AISI 316L stainless steel using niobium as filler material. Pulsed Nd:YAG laser was used to achieve different mixing conditions for the materials. The results show that the weld seams, despite the use of filler material, have a high tendency to crack due to the formation of hard intermetallic compounds. However, by optimizing the process parameters, crack-free specimens can be obtained through uniform mixing of critical alloy elements. The use of multiple weld seams increases the maximum loads and lap-shear forces, exceeding the yield strength of the stainless steel. The biocompatibility of the niobium filler material makes this dissimilar material combination suitable for future medical technology applications.