Interfacial Microstructure and Shear Strength of TC4 Titanium Alloy/Stainless Steel Vacuum Brazed Joint

TC4 and 1Cr18Ni9Ti were brazed by using Ag-28%Cu brazing filler metal under the conditions of brazing temperature of 800-890 ℃ and heating times of 2-25 min, and the interfacial microstructure and shear strength were investigated. The results show that Ti elements in TC4 dissolved into brazing filler metal and diffused to the interface of brazing filler metal and stainless steel, FeTi+Cu phase was formed at the interface, and thus the problem for the brazing filler metal being difficult to wetting the stainless steel was solved. The interface structure of brazed joints was TC4/ Ti/ Ti2Cu/ TiCu/Ag+Cu/Ti40Cu60-xFex/TiFe/1Cr18Ni9Ti. The maximum shear strength was 103 MPa when the brazing temperature was 830 ℃ and heating time was 5 min.