Diffusion bonding between commercially pure titanium and micro-duplex stainless steel

Diffusion-bonded joints between commercially pure titanium and micro-duplex stainless steel were prepared in the temperature range of 800–950 °C for 1.5 h under 3 MPa uniaxial load in vacuum. The diffusion bonds were characterized using light and scanning electron microscopy. The composition of the reaction products were determined by energy dispersive spectroscopy. Up to 850 °C, α-Fe + λ and λ + FeTi phase mixtures were formed at diffusion interface; however α-Fe + λ, λ + FeTi and FeTi + β-Ti phases mixtures were formed at 900 °C and above. The presence of these intermetallics was confirmed by X-ray diffraction technique. The maximum tensile strength of ∼96% of Ti and shear strength of ∼81% of Ti along with 6.9% ductility were obtained for the diffusion couple processed at 850 °C due to the finer width of intermetallic phases. With a rise in the joining temperature the bond strength drops owing to an increase in the width of reaction products.