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

ABSTRACT

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 ∼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.

KEYWORDS:

• Friction stir spot welding
• aluminium alloy
• Fe₃O₄ nanoparticle
• grain refinement
• microhardness
• failure load
• fracture energy

Disclosure statement

No potential conflict of interest was reported by the authors.