Synthesis of radar-absorbing NiFe 2 O 4 nanoparticles and effects of pass number on mechanical properties of AA7075/NiFe 2 O 4 surface nanocomposites fabricated by FSP

Abstract In this paper, first, the desired NiFe 2 O 4 nanoparticles were produced using the hydrothermal method then the AA7075/NiFe 2 O 4 surface nanocomposite was fabricated by the friction stir processing (FSP) method. The results show that the hydrothermal method is very suitable for making NiFe 2 O 4 nanoparticles with a fine and uniform structure that the fabricated nanoparticles have a superparamagnetic property that can be used for radar-absorbing coatings. The nanoparticles were well distributed in the base AA7075 aluminum alloy sheet in addition to the fine-grained structure achieved using FSP. The microhardness of the FSPed and surface nanocomposites were significantly improved compared to the base metal and increased with the increasing pass number of FSP. Also, the tensile properties consist of the ultimate tensile strength (UTS), formability, and toughness decrease with increasing the number of FSP passes.