Microstructure and strength of vacuum brazed joints of TiAl based alloy to 40Cr steel

摘要

Vacuum brazing of TiAl based alloy to 40Cr steel has been carried out at 1173 K for 0.5 - 40 min using Ag - Cu - Ti filler metal. The microstructural analyses indicate that three reaction products, Ti(Cu,Al)_2, an Ag based solid solution (Ag(s.s.)), and TiC, are present in the brazing seam, and the interfacial structure of the brazed joint is TiAl/Ti(Cu,Al)_2 + Ag(s.s.)/Ag(s.s.) + Ti(Cu,Al)_2/TiC/40Cr. The experimental results show that the shear strength of the brazed TiAl/40Cr joints decreases as the brazing time increases, and it is up to 175 MPa when the joint is brazed at 1173 K for less than 2 min.