Ultrahigh-strength friction stir spot welds of aluminium alloy obtained by Fe3O4 nanoparticles

摘要

The present research was aimed at simultaneous increase in strength and fracture energy of friction stir spot weld of Al-5083 alloy via reinforcing by Fe3O4 nanoparticles. Compared to non-reinforced welds, failure load and fracture energy of reinforced welds increased up to similar to 115 and 560%, respectively. These findings were discussed in the light of grain refinement as well as considerable increase in hardness of fracture location due to the presence of sub-micron and nano reinforcing particles (RPs). Fe3O4 nanoparticles were transformed to Al-Fe intermetallics due to their small size and heat generated during the welding process. The stir zone of reinforced welds consisted of three different grain structures among which the finest one was related to the composite structure containing well-distributed RPs in the aluminium matrix.