Wire Arc Additive Manufacturing (WAAM) belongs to the category of Direct Energy Deposition (DED)-based Additive Manufacturing (AM) in which the feedstock material is in the form of metallic wire. The wire melts under the action of a welding arc the molten material is deposited on a substrate. Successive bead deposition in a layer-upon-layer manner (along the build direction) develops the final 3D part. In order to build a cross-section/ layer, multiple beads need to be deposited one-after-another onto the horizontal plane in accordance with a given pattern. WAAM is characterized by its high material deposition rate (when compared to the powder-based AM techniques) and is suitable towards fabricating parts which are medium-to-large sized, possessing low-to-medium level of design intricacy. The present dissertation focuses on microstructure and mechanical property characterization of Cold Metal Transfer (CMT) + Metal Inert Gas (MIG) welding based WAAMed SS 308L and Inconel 718 parts. The complex heat interaction phenomena that take place during execution of WAAM process is also studied herein.