Friction Welding of Titanium to Stainless Steel Using Al Interlayer

Dissimilar friction welding between titanium and 304 austenitic stainless steel with aluminum as insert layer was examined to amend the joint properties and interface characteristics. To insert the interlayer into the joint, a two-step method was used. The resultant of the joint interfaces was characterized to reveal the reactions between interlayer and parent metals using scanning electron microscope, X-ray diffraction and electron probe micro-analyzer. Microhardness and tensile tests were used to evaluate the mechanical properties of the joints. It was observed that the development of brittle phases of FeTi and CrTi in the welded joint was successfully precluded using aluminum interlayer, whereas the presence of other phases which were in ductile nature compared to the FeTi- and CrTi-type phases of AlTi and FeAl was identified. The absence of reaction compounds and brittle phases ensued improvement in the mechanical and microstructural properties of the aluminum insert layer joints.