Joint properties and microstructure of diffusion-bonded grade 2 titanium to AISI 430 ferritic stainless steel using pure Ni interlayer

Diffusion welding/bonding has been successfully used to joint dissimilar metals widely. In this study, pure Ti and AISI 430 ferritic stainless steel plates were joined through diffusion welding using a Ni interlayer at various temperatures (800, 825, 850 and 875 °C), holding times (15, 30, 60 and 120 min) and under a constant pressure (3 MPa) under argon shielding media. The welded joints were subjected to tensile-shear tests and hardness tests in order to determine their interfacial strength. In addition, microstructural properties of the joined interface were examined using optical and scanning electron microscope (SEM). The tensile-shear test results showed that the fractures occurred mostly in the interface of the Ni-ferritic stainless steel web at lower temperatures. It was seen from the hardness results that the highest hardness value was obtained for the titanium side and the hardness values increased with increasing welding temperature and holding time. SEM/EDS examinations showed that the diffused atoms and diffusion distance increased depending on the increasing temperature and holding time.