Copyright: © the author(s), publisher and licensee Technoscience Academy. This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited International Journal of Scientific Research in Science, Engineering and Technology Print ISSN: 2395-1990 | Online ISSN : 2394-4099 (www.ijsrset.com) doi : https://doi.org/10.32628/IJSRSET 66 Experimental Investigation on Micro Structure and Mechanical Behavior of AA 6063 - 7075 Dissimilar joint using Activated TIG Welding Rajiv Kumar a , Harmesh Kumar Kansal b , S. C. Vettivel c a Research Scholar, UIET, Panjab university, Chandigarh, India b Professor, UIET, Panjab university, Chandigarh, India c CCET (Degree Wing), Chandigarh, India Article Info Publication Issue : Volume 10, Issue 1 January-February-2023 Page Number : 16-38 Article History Accepted : 05 Jan 2023 Published: 19 Jan 2023 ABSTRACT This paper is mainly focused on the Activated Tungsten Inert gas welding (ATIG) characterization and mechanical behavior of AA 6063 - 7075 dissimilar joint using TiO2 flux with the filler of AA 5356 and compared with conventional TIG. The characterization of the Base Material (BM), Fusion Zone (FZ), Heat Effected Zone (HAZ) and partially melted zone are carried out using the Optical Microscope. The quality of the weld is characterized using Ultrasonic assisted non destructive evaluation. A-Scan result confirms that the ATIG welded samples having more DOP and less bead width as compared to conventional TIG. The recorded tensile strength of conventional TIG and ATIG welded with flux (TiO2) sample 135 and 173 MPa respectively. Keywords: TIG welding, Activated TIG welding, Microstructure, Flux I. INTRODUCTION Activated Tungsten Inert Gas (ATIG) welding is a technique that can produce an enhanced weld penetration in a single pass. There are certain cases because of which the use of this technique is restricted such as inferior weld surface quality and inferior metallurgical and mechanical properties and also its use, especially in industries. Different results are obtained by performing A-TIG welding on different types of steels and fluxes provided [1]. It is a process involving the application of a thin coating of flux over the joint area before welding and it helps in increasing the weld penetration at the same parameters than the conventional TIG welding. A summary of the effect of different types of fluxes on the different types of steels by the researchers has been discussed [2]. The phenomenon of sensitization and hot cracking are always of top-most importance while performing such a task. Welding process like limit passes, removal of filler metal and lowering the heat input