Joining 304 Stainless Steel and TC4 Alloy Using Ag Foil Interlayer by Plasma Activated Sintering

摘要

Dissimilar metals 304 stainless steel (SS) and TC4 alloy were bonded using Ag foil interlayer by plasma activated sintering. The microstructure, mechanical properties and fracture failure of bonded joints were investigated. When bonding temperature was below 600°C, the voids appeared at 304 SS/Ag foil interface. As bonding temperature was above 600°C, the 304 SS/Ag foil/TC4 joints were free of the voids or cracks, and TiAg intermetallic compounds (IMC) nucleated above 600°C, and grew into TiAg IMC layer at Ag foil/TC4 interface with the increasing of bonding temperature. The joint free of the voids or cracks was successfully obtained at 600°C, of which the average shear strength was 125 MPa and the fracture failure was the mixture of ductile rupture in Ag and brittle rupture in TiAg IMC. The formation of TiAg IMC layer decreased the bonding strength of joints. Fracture failure mainly occurred at TiAg IMC layer which is typical brittle fracture when bonding temperature was above 650°C.