Experimental Review on Friction Stir Welding of Aluminium Alloys with Nanoparticles

To reduce environmental impacts and ensure competitiveness, the fabrication and construction sectors focus on minimizing energy and material usage, which leads to design requirements for complex structures by joining of similar and dissimilar materials. Meeting these industrial demands requires compatible materials with improved properties such as good weight-to-strength ratios, where aluminum (Al) and its alloys are competing candidates for various complex applications. However, joining Al with fusion welding processes leads to joint deterioration. Friction stir welding (FSW) produces joints at temperatures below the melting temperature, thus avoiding flaws associated with high heat input, yet requires improvement in the resultant joint properties. Recent studies have shown that nanoparticle reinforcement in FSW joints can improve weld properties. The main focus of this study is to critically review similar and dissimilar friction stir welding of AA5083 and AA6082 with carbide and oxide nanoparticle reinforcement. The study also discusses the effect of welding parameters on reinforcement particles and the effect of nanoparticle reinforcement on weld microstructure and properties, as well as development trends using nanoparticles in FSW. Analysis shows that friction stir welding parameters have a significant influence on the dispersion of the reinforcement nanoparticles, which contributes to determining the joint properties. Moreover, the distributed nanoparticles aid in grain refinement and improve joint properties. The type, amount and size of reinforcement nanoparticles together with the welding parameters significantly influence the joint properties and microstructures in similar and dissimilar Al welds. However, research is still required to determine the strengthening mechanism used by nanoparticles and to assess other nanoparticle additions in FSW of Al alloys.