Novel welding of Al0.5CoCrFeNi high-entropy alloy: Corrosion behavior

Laser welding of Al0.5CoCrFeNi high-entropy alloy has been studied in detail. Base metal (BM) shows equiaxed grains with three different regions; (a) Cr–Fe rich, (b) Al–Ni rich phases and (c) Al-rich particle. Laser welding has resulted in evolution of columnar dendritic microstructure with dissolution of Al rich particles in the weld metal (WM), where dendrites are Cr–Fe rich and interdendrites are Al–Ni rich regions. The corrosion experiment shows higher corrosion current density (2.83 × 10−5 mA/cm2) in WM than the BM (8.63 × 10−6 mA/cm2) implies higher corrosion rate. However, the WM exhibits higher (nobler) corrosion potential as compared to BM. Due to this nobler potential, WM acts as the cathode and the BM act as an anode when weldment (BM + WM) is analyzed. Hence, the weldment (BM + WM) exhibits lower corrosion current density (4.11 × 10−6 mA/cm2) like BM.