Interface microstructure and strength properties of diffusion bonded joints of titanium–Al interlayer–18Cr–8Ni stainless steel

Abstract

In the present investigation, diffusion bonded joints between titanium and 18Cr–8Ni stainless steel using 120 μm thick Al interlayer were produced at 650 °C temperature for 15, 30, 45, 60, 90, 120, 150 and 180 min under 4 MPa pressure in vacuum. The interface microstructures of the bonded assemblies were observed in a scanning electron microscope using backscattered mode with energy dispersion spectroscopy and X-ray diffraction technique. Al 2Fe layer intermetallic has been observed at the SS–Ti interface, however at the Al–Ti interface AlTi + Al 3Ti phase mixture was formed for all the processing times. The maximum tensile strength of ∼266 MPa along with 5.6% elongation was obtained for the diffusion couple processed for 90 min and the bonded samples were fractured through the Al–Ti interface for all the processing times.