Thermoplastic bonding of TiAl-based alloy and YSZ ceramic utilizing a Ni60Nb40 metallic glass as the filler metal

Abstract

Achieving a reliable bond between advanced ceramics and high-temperature application alloys for high-temperature applications can greatly enhance the operating temperature range of vital components like engines and turbines. In this work, we have achieved success in bonding Yttria-stabilized zirconia (YSZ) ceramics with TiAl-base alloys through the use of a novel ceramic-metal joining method called thermoplastic bonding (TPB). Compared with traditional brazing methods, TPB requires a lower bonding temperature that is below the melting point of the filler. This advantage enables TPB to use fillers with higher melting points, resulting in improved high-temperature performance of the joint. Furthermore, TPB substitutes the conventional liquid phase bonding method in brazing with a solid phase bonding process. This not only diminishes residual stress on the joint but also prevents the generation of fragile oxides, which effectively enhances the strength of the joint. Shear tests have demonstrated that TPB joints possess excellent room temperature strength, reaching up to 141 MPa. Remarkably, the TPB joint retains remarkable strength, with a value of approximately 84 MPa even when exposed to a high temperature of 600 °C. These test results proved that TPB was an effective strategy for successfully realizing high-strength and high-temperature resistant metal-ceramic joins.