Electrochemical Study of Diffusion Bonded Joints between Micro-duplex Stainless Steel and Ti6Al4V Alloy

In the present study, corrosion behavior of diffusion bonded joints formed between micro-duplex stainless steel (MDSS) and Ti6Al4V alloy (TiA) (at 900 °C for 60 min under 4 MPa uniaxial pressure in vacuum) was investigated in 1 mol/L HCl and 1 mol/L NaOH solutions using various electrochemical measurements such as open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PD). For comparison, corrosion behavior of base metals (MDSS and TiA) was also evaluated. Bonded joint was characterized by light optical microscopy and scanning electron microscopy using backscattered electron mode. 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 ∼556.4 MPa and ∼420.2 MPa, respectively.