Activated tungsten inert gas (ATIG) welding has a good depth of penetration (DOP) as compared to the conventional tungsten inert gas (TIG) welding. This paper is mainly focused on ATIG characterization and mechanical behavior of aluminum alloy (AA) 6063-T6 using SiO₂ flux. The characterization of the base material (BM), fusion zone (FZ), heat affected zone (HAZ) and, partially melted zone is carried out using the suitable characterization methods. The weld quality is characterized using ultrasonic-assisted non-destructive evaluation. A-scan result confirms that the ATIG welded samples have more DOP and less bead width as compared to conventional TIG. The recorded tensile strength of ATIG with SiO₂ is better than the conventional TIG welding. The failure mode is ductile for ATIG welding with larger fracture edges and is brittle in the case of conventional TIG welding.

In this work, a comparative study on the ballistic behaviour of friction stir processed AL6061 targets had been made. Base Metal AL6061 (BM) plates with 25 mm thickness were friction stir processed by adding Multi Walled Carbon Nano Tubes (MWCNT) and Graphene (G), producing AL6061-MWCNT and AL6061-G surface composites. Optical microscopy and microhardness test on BM, AL6061-MWCNT and AL6061-G samples were performed as per the standard procedure. It was noticed that uniform dispersion of ceramic particles and refined grains were obtained for the friction stir processed surface composites. From the microhardness test, it was perceived that friction stir processing had induced strengthening of surface composites, hence increasing the microhardness of AL6061-MWCNT and AL6061-G by ~60.3% and ~73.6% respectively. Also, ballistic experiments were conducted at 680±10 m/s by impacting Ø7.62×51 mm projectiles. AL6063 backing plates were placed to compare the ballistic behaviours AL6061-MWCNT and AL6061-G targets by depth of penetration. It was noted that the depth of penetration of AL6061-MWCNT and AL6061-G targets were 37.81% and 65.84% lesser than the BM target. Further, from the results of Post ballistic microscopy it was observed that the microstructure near and away from the penetration channel edge looks unchanged in BM target. However, the AL6061-MWCNT and AL6061-G targets showed considerable change in their morphology, by forming Adiabatic Shear Bands.