Processing of friction stir welded AA6061-T6 joints reinforced with nanoparticles

Abstract

The solid-state joining of AA6061-T6 - 0.2% Al2O3 (15 nm) and TiO2 (15 nm) nanoparticles via friction stir welding was done. The microstructure, metallurgical, and mechanical properties of weldments were examined and compared with FSW weld Without Nanoparticle (WNP) weldment and base material. Results reveal that the WNP weld welded at many FSW conditions, while in the case of weldments With Al2O3 Nanoparticle (WAL) and With TiO2 Nanoparticle (WTI)), the working window was narrower. Such welds were only feasible at high heat inputs concerning high rotational speed. Microstructural and metallurgical studies reveal the expansion of the Weld Nugget Zone (WNZ) on the retreating side, as a result of high heat input and microhardness for WAL weldment than WTI weldment. Whereas the overaging effect caused due to frictional heat leads to a decrease in microhardness of WTI compared to WAL weldment. The grain refinement in WNP weldment with appreciable microhardness is governed by Dynamic Recrystallization (DRX). The tensile tests showed high tensile properties of WAL and WTI weldments than WNP weldments.