Abstract

Dissimilar metal joining of Ti alloys to steels has gained considerable attention in the design of lightweight structures. However, it is difficult to produce robust and reliable Ti/steel joints by fusion welding (e.g., arc [1] and laser welding [2,3]) or solid-state joining methods (e.g., friction [1,4], friction stir [5-7], and diffusion bonding [8-11]) due to the significant mismatch in thermal physical properties and poor metallurgical compatibility between the two materials. The major metallurgical challenge of joining Ti alloys to steels is the formation of hard and brittle intermetallic phases regardless of the dilution ratio, such as FeTi and Fe₂ Ti, which could lead to cracking and thus reduced joint strength.