Effects of a nickel-based alloy interlayer on electrically assisted pressure joining of pure titanium and stainless steel 304

Abstract

This study focuses on the solid-state joining of commercially pure titanium (CP-Ti) and stainless steel 304 (SUS304) using electrically assisted pressure joining. A nickel-based alloy foil acting as an intermediate layer (Ni interlayer) is inserted between two base materials during joining to avoid the formation of a detrimental TiFe intermetallic due to direct contact of the CP-Ti and SUS304. The solid-state joining process can be completed within 2 s. The effectiveness of incorporating the Ni interlayer on joint quality is systematically investigated by comparing joints made with and without the use of a Ni interlayer. Microstructure analysis reveals that the Ni interlayer plays a critical role in improving joint quality by forming a nanocrystal structure and preventing the formation of TiFe intermetallic. Furthermore, the joint with a Ni interlayer increases the joint shear strength by at least 50% more than a joint without a Ni interlayer in the same joining period and exhibits tensile ductile fracture at the heat-affected zone in the CP-Ti side during tension. The present study provides valuable insights into the benefits of Ni interlayers in the rapid and reliable creation of solid-state joints between CP-Ti and SUS304 using electrically assisted pressure joining.