Titanium to steel joining by spark plasma sintering (SPS) technology

The bonding of Ti–6Al–4V to low alloy steel (AISI4330) using SPS technique in the 850–950 °C temperature range was examined. The formation of a thin (∼1 μm) titanium carbide interfacial layer was observed with a thickness only slightly dependent on the joining temperature. This layer separates the joined metals and prevents the formation of Fe–Ti intermetallics in the bonding zone. The maximal tensile strength of the joints (of about 250 MPa) was achieved for bonding at 950 °C for 3.6 ks. The formation of the titanium carbide layer and its evolution are discussed based on the isothermal section of the ternary Fe–Ti–C phase diagram.