Electrochemical Study of Diffusion Bonded Joints between Micro-Duplex Stainless Steel and Ti6Al4V Alloy
In the present study, corrosion behavior of a diffusion bonded interface formed between micro-duplex stainless steel (MDSS) and a mixed titanium alloy (Ti6Al4V) formed at 900°C for 60 minutes under 4MPa uniaxial pressure in vacuum has been investigated in 1M HCl and 1 M NaOH solutions using various electrochemical measurements such as Equilibrium Potential (EP), Electrochemical Impedance Spectroscopy (EIS) and Potentiodynamic Polarization (PD). For comparison, corrosion behavior of base metal alloys, MDSS and Ti6Al4V have also been also characterized. Bonded interface has been characterized in light optical microscopy and scanning electron microscopy using back scattered electron. The layer wise σ phase and λ+FeTi phase mixture has been observed at the bond interface and the bond tensile strength and shear strength were ~556.4MPa and ~420.2MPa, respectively. The corrosion rates of the bonded joint are intermediate to the corrosion rates of MDSS and Ti6Al4V alloy.