Abstract:Intermetallics TiAl was diffusion-bonded to steel 40Cr in vacuum furnace with interlayer V/Cu. The results show that infinite sosoloid that made for bond performance is formed at the interface of V/Cu and Cu/40Cr, and three acting layers are formed at the interface of TiAl/V including Ti₃Al layer at TiAl side, intermittent V₅Al₈ layer in the middle and Ti-V sosoloid at V side. Fragile reactors V₅Al₈ arising at the interface lead to bad performance of joints, and the strength of the joint is 200MPa, while it was still higher than the strength of the joint intermetallics TiAl to 40Cr steel diffusion-bonded directly. Intermetallic TiAl and 40Cr steel are diffusion-bonded successfully by using a composite isolation layer V/Cu.

Key words:  diffusion bonding; microstructure; TiAl; intermetallics; filler metal