Low temperature diffusion bonding of Ti-6Al-4V and duplex stainless steel

The binary phase Ti-6Al-4V alloy was joined with duplex stainless steel (DSS) by the diffusion bonding process in a lower temperature range of 650–800 °C. An axial load of 10 MPa was applied for 30 min to create the joint under vacuum state. Microstructural Characterisation of the bonded interface was analyzed using optical and scanning electron microscopy. The composition of elements presented near the bonded interface was measured using Energy Dispersive Spectroscopy (EDS). The interface layers such as α-Fe + λ, λ + FeTi and β-Ti were identified in diffusion of Ti alloy and DSS at low temperature range. The interlayer growth kinetics and activation energy were evaluated using Arrhenius relationship. The diffusion coefficient of the interface elements under different temperatures were determined by Fick’s law. The quality of the bond was assessed by the mechanical shear test and microhardness. The fractured surfaces were analyzed and fractographs were prepared using XRD for the joint, bonded at 750 °C which had more shear strength by hard intermetallic of Fe-Cr-Ti.

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