This paper analyzes the friction stir welding process in both its conventional form, FSW, and its hybrid variant, FSW-TIG, applied to 2 mm thick butt-welded Cu-DHP copper sheets. The FSW process was selected because it allows copper to be joined in the solid state without melting the material, thereby reducing the risk of defects commonly associated with fusion welding and facilitating the formation of a fine, homogeneous microstructure. The research focused on determining the most suitable technological parameters, including rotational speed, welding travel speed, and, in the case of the hybrid process, electric current intensity, in order to obtain welded joints with mechanical properties close to those of the base material. Weld quality was evaluated through tensile testing, Vickers microhardness measurements, macrostructural and microstructural analyses.

The addition of the TIG heat source increased the temperature in the welding area, improving material plasticization and ensuring a more stable flow around the tool. The microhardness analysis showed a general decrease in values with increasing welding temperature, indicating that excessive heat input may cause local softening of the material. Overall, the study shows that the hybrid FSW-TIG process can improve the weldability and joint quality of thin Cu-DHP copper structures.