Development of processing windows for diffusion bonding of Ti–6Al–4V titanium alloy and 304 stainless steel with silver as intermediate layer

As titanium alloy is chemically reactive, it is very difficult to join by conventional welding techniques. Titanium alloys can easily pick up nitrogen and oxygen from the atmosphere. In the fusion welding method, brittle intermetallic compounds are formed when joining titanium alloy and stainless steel, which decrease the mechanical behavior of the couples. Hence, for joining of titanium alloy, diffusion bonding is recommended. This work dealt with the measurement of feasible process parameters for diffusion bonding of Ti–6Al–4V and AISI 304 stainless steel with silver as an intermediate layer. The quality of the bonds was confirmed by the lap shear test and microstructural analysis. With the experimental results obtained, diffusion bonding windows were constructed and this will act as reference maps to identify the process parameters for obtaining defect free bond. Bonding was successful in the temperature range of 750–800 °C. Maximum lap shear strength was achieved under a bonding pressure of 5 MPa and holding time of 90 min.