Investigating Stress Corrosion Cracking of AA7075 Aluminum Alloy Processed using Additive Friction Stir Deposition

High-performance structures are needed for many structural applications, including land, air, and marine-based transportation systems. To that end, additive friction stir deposition (AFSD), a solid-state manufacturing process that works on the principles of friction stir processing, is quite a promising additive manufacturing tool with the potential to create metallic materials with desired properties. This study aims to understand the susceptibility of AA7075 aluminum alloy processed via AFSD to stress corrosion cracking (SCC). The SCC was evaluated by performing a slow strain-rate tensile testing in 3.5 wt.% NaCl solution at room temperature. The tensile testing was performed at 10^-6, 10^-5, and 10^-4 s^-1 initial strain rates (constant crosshead velocity test). For comparison, AA7075-T6 (used as a feedstock during AFSD) was subjected to SSRT testing under similar conditions. The microstructural characterization and fractography were performed using electron backscattered diffraction and scanning electron microscope. A comparative study with the feedstock material elucidated the impact of AFSD on SCC resistance, providing an understanding of the efficiency of AFSD processing in addressing SCC risks in transportation systems.