Evaluation of interface microstructure and mechanical properties of the diffusion bonded joints of Ti–6Al–4V alloy to micro-duplex stainless steel

In the present investigation, Ti–6Al–4V and micro-duplex stainless steel was diffusion bonded in vacuum. The layer wise σ phase and λ + FeTi phase mixture were observed at the bond interface when bonded joints was processed at and above 850 °C for 90 min and at 800 °C for 120 min and longer bonding time. Effect of bonding temperature and time on the strength properties at room temperature were evaluated. The maximum tensile strength of ∼510.1 MPa and shear strength of ∼397.5 MPa along with 6.5% elongation were obtained for the diffusion couple processed at 850 °C for 90 min. Fracture surface observation in SEM using EDS demonstrates that, failure takes place through λ + FeTi phase when bonding was processed at 850 °C for 90 min and at 800 °C for 120 min, however, failure takes place through σ phase for the diffusion couples processed at and above 900 °C for 90 min and at 800 °C for 120 min and longer bonding time.

► Study on diffusion bonding between titanium alloy and micro-duplex stainless steel has been carried out for industrial applications.
► The processing parameters (like temperature and time) was varied to get the maximum strength of the above dissimilar materials joint.
► Microstructural aspects of the interface has been co-related with mechanical properties.