Effect of nanoparticles addition on dissimilar joining of aluminum alloys by friction stir welding

The purpose of this study was to examine the effect of adding Nano particles such as Nano Carbon Tube during Friction Stir Welding (FSW) on dissimilar Al alloy joints. More specifically, both FSW and Friction Stir Processing (FSP) were performed simultaneously to investigate the effect of adding Nano particles on mechanical properties and microstructure of the weld zone for joining AA5754-H22 and AA6063-T4aluminum alloys. Reliability of the joints was tested by non-destructive tests such as visual inspection, ultrasonic, and radiography. The global mechanical behaviors of dissimilar welds were similar to that of the base material. Important losses in ductility were also reported for dissimilar welds. Microstructural evaluation of fractured surfaces indicated that ductile fracture was the major mechanism of similar and dissimilar welds. We expected that the locks for dislocation moving would improve the mechanical properties of the weld zone. Also, the friction coefficient in the two-passes welded sample was about 30% lower than the friction coefficient of the base metal. On the bases of the wear resistance of hardness and the coefficient of friction, it was concluded that the wear resistance of the surface Nano-composite produced had also increased in the stir zone.