The effect of SiO2 nano powder addition to the joint developed between low carbon steels by friction stir brazing

In the present study, the microstructure and the mechanical properties of lap joint developed between low carbon steels using friction stir brazing (FSB) method while SiO2 nano-particles were incorporated in joint were investigated. Sn-Pb braze alloy was used as braze alloy. The bonds were characterized by optical microscopy (OM) and shear and micro hardness tests were carried out as mechanical experiments. The results showed that a strong joint could be developed between parent metals due to diffusion of Sn and Pb elements. Additionally, the joint was strengthened as SiO2 second phase particles were incorporated in the joint. SiO2 nano-particles act as second phase particles and correspondingly, decrease the movement of dislocations and increase the strength.