A New Approach for Using Interlayer and Analysis of the Friction Welding of Titanium to Stainless Steel

Abstract

Dissimilar material joining is often more difficult than joining the similar material or alloys with minor differences in physical properties and composition. The formation of deleterious intermediate phases consisting of intermetallic compounds during welding of titanium and stainless steel is a challenge to the welding processes, for decades. Friction welding has been used in an attempt to reduce formation of intermetallic compounds through inserting an interlayer material. In recent years, a number of approaches have been developed to insert interlayer between the substrates to avoid the metallurgical incompatibility. In this research, dissimilar joint of titanium and stainless steel were welded effectively using a new technique of electrodeposited nickel coating on one of the substrate (stainless steel) as interlayer. The bonding interface of the joints was characterized using optical microscopy, scanning electron microscopy and energy dispersive spectroscopy. Tensile strength of the nickel interlayer joints was higher than the direct joints. The microstructural characterization in the interface of titanium and stainless steel showed the absence of brittle Fe–Ti intermetallic compounds, which was a condition attributed to the use of interlayer technique. Whereas, the characterization of interface were identified as the presence of Ti–Ni phases which were more plastic than Fe–Ti intermetallic compounds.