Diffusion bonding of Ti-45Al-7Nb-0.3W alloy by spark plasma sintering

Spark plasma sintering (SPS) is a new method for diffusion bonding of TiAl alloys. A powder metallurgical (PM) Ti-45Al-7Nb-0.3W (at%) alloy was bonded using SPS. The effects of bonding temperature, pressure and time on the microstructure and mechanical properties of the alloy were investigated. Complete metallurgical bonding can be produced at temperatures above 1150 °C. The tensile strength of specimens depends on the percentage of metallurgical bonding and the interfacial microstructure, and it can exceed the strength of the base material. The fracture mode changes with bonding temperature, transforming from intergranular fracture at the bonding interface to cleavage fracture in the substrate. Due to the activation process of SPS, metallurgical bonding can be achieved at a lower pressure and shorter time than those of the traditional diffusion bonding process.