DC‐driven ultrafast transient liquid phase bonding of 3YSZ and GH3128 superalloy using Ni interlayer

Abstract

A direct current (DC)‐driven transient liquid phase bonding strategy was proposed for joining 3 mol% Y2O3‐stabilized ZrO2 (3YSZ) and GH3128 superalloy with a Ni interlayer. The DC application triggered the rapid formation and diffusion of metallic Zr in 3YSZ and chemical reactions at the 3YSZ/Ni interface. The formed Ni–Zr eutectic liquid well wetted 3YSZ and hence completely filled the bonding gap in seconds. Eutectic structures in the joints were eventually transformed into Ni–Zr intermetallic compounds or a Ni‐based solid solution. The remaining Ni interlayer effectively alleviated residual stress through plastic deformation during cooling stage, and thereby contributed substantially to the high joint strength. Under the joining conditions of a current density of 30 mA/mm2, an energization time of 30 s, and a joining temperature of 1100°C, the obtained joints exhibited a maximum shear strength of 188 ± 8 MPa. This paper proposes an economical and reliable method for the rapid preparation of YSZ/metal joints for high‐temperature applications.