Evaluating the Corrosion Susceptibility of Semi-Solid Welded Al-Mg-Si Alloy in Acidic and Marine Environment

The Al-Mg-Si alloy is recognized as an engineering material currently gaining attention in the aerospace industry due to its high strength-to-weight ratio. The welding of these materials has been recently improved using a technique known as thixo-joining, also referred to as semi-solid welding. To investigate the susceptibility of the welded Al-Mg-Si to corrosion in acidic and marine environments, various welding temperatures (34°C, 100°C, 200°C, and 300°C) were utilized before exposure to these harsh conditions. The preparation of the coupons adhered to accepted standards and they were subsequently subjected to a weight loss gravimetric and linear polarization technique for corrosion investigation. Observations indicated improved corrosion resistance when the gravimetric approach (weight loss plot) was used. The presence of globules, in comparison with the parent metal (PM), served as crack arresters to the structures, thus reducing the susceptibility to corrosion in both marine and acidic environments.