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

In the present investigation, diffusion bonded joints between titanium and 18Cr-8Ni stainless steel using 120 mu m thick Al interlayer were produced at 650 degrees 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. Al2Fe layer intermetallic has been observed at the SS-Ti interface, however at the Al-Ti interface AlTi+Al3Ti 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 mm and the bonded samples were fractured through the Al-Ti interface for all the processing times. (C) 2010 Elsevier B.V. All rights reserved.