The effect of interlayer thickness on liquid state diffusion bonding behavior of dissimilar stainless steel 316/Ti-6Al-4V system

• Liquid state diffusion bonding of stainless steel 316 to Ti-6Al-4 V was performed.
• Effect of the joint width on the microstructure of joint was discussed.
• Effect of interlayer thickness on mechanical properties of the joint was studied.

The liquid state diffusion bonding mechanism of stainless steel 316 to Ti-6Al-4 V using pure Cu interlayer has been investigated at 1100 °C for 60 min bonding time. The microstructure of joint zone was analyzed in detail by scanning electron microscope and energy dispersive spectroscopy. The microhardness and shear strength tests were also applied to characterize mechanical properties of the joints. The results showed that increasing the interlayer thickness led to the extension of diffusion zone and the increase of final joint width. The maximum shear strength of 284 MPa was obtained for the bond made with 50 µm thick interlayer while with an increase in interlayer thickness, the shear strength values decreased to 145 MPa that could be attributed to formation of brittle intermetallics such as Cu2Ti and CuTi at the interface.