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 if phase and lambda + FeTi phase mixture were observed at the bond interface when bonded joints was processed at and above 850 degrees C for 90 min and at 800 degrees 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 similar to 510.1 MPa and shear strength of similar to 397.5 MPa along with 6.5% elongation were obtained for the diffusion couple processed at 850 degrees C for 90 min. Fracture surface observation in SEM using EDS demonstrates that, failure takes place through lambda + FeTi phase when bonding was processed at 850 degrees C for 90 min and at 800 degrees C for 120 min, however, failure takes place through sigma phase for the diffusion couples processed at and above 900 degrees C for 90 min and at 800 degrees C for 120 min and longer bonding time. (C) 2011 Published by Elsevier B.V.