Interfacial reaction and microstructure investigation of TC4/Co/4J29 diffusion-bonded joints

The diffusion bonding of TC4 titanium alloy and 4J29 kovar alloy was conducted using pure Co interlayer. The results showed that maximum tensile strength of 58.5 MPa was acquired for bonded joint made at 825 degrees C. At titanium alloy side, due to formation Ti-Co phases, such as TiCo3, TiCo2, TiCo and CoTi2, brittleness of bonded joints was enhanced. Furthermore, with increase in bonding temperature, tensile strength of bonded joints gradually decreased because of the production of Ti-Co intermetallic compounds with a thicker thickness. (C) 2019 Elsevier B.V. All rights reserved.