Microstructure and Mechanical Properties of Joints of Titanium with Stainless Steel Performed using Nickel Filler

Abstract

Diffusion brazing was performed between titanium (Grade 2) and stainless steel (X5CrNi18-10) using as a filler a nickel foil at the temperatures of 850, 900, 950 and 1000°C. The microstructure was investigated using light microscopy and scanning electron microscopy equipped with an energy dispersive X-ray system (EDS). The structure of the joints on the titanium side was composed of the eutectoid mixture αTi+Ti 2 Ni and layers of intermetallic phases Ti 2 Ni, TiNi and TiNi 3 . The stainless steel-nickel interface is free from any reaction layer at 850°C, above this temperature thin layer of reaction appears. The microhardness measured across the joints reaches higher values than for titanium and stainless steel, and it achieves value from 260 to 446 HV. The highest shear strength (214 MPa) was achieved for joints brazed at 900°C.

A Review on Diffusion Bonding between Titanium Alloys and Stainless Steels

“…In terms of intermetallic formation in the joint, the maximum tensile strength is only 214 MPa. Szwed and Konieczny [78] performed diffusion brazing to join titanium and stainless steel using a nickel foil as a transit layer. Eutectoid mixture α-Ti + Ti 2 Ni and layers of intermetallic phases Ti 2 Ni, TiNi, and TiNi 3 composed titanium side.…”