Contact reactive brazing of Ti53311S alloy using Cu foil as interlayer: Interfacial microstructure and joining properties

Contact reactive brazing of Ti53311S alloy was extensively evaluated using Cu foil as interlayer within the range of 940–1020 °C for 10 min. Effect of brazing temperature on the interfacial microstructure and its evolution as well as joining properties were investigated in detail. TiCu and Ti3Cu4 intermetallic compounds formed in joint by isothermal solidification and peritectic reaction (TiCu + L → Ti3Cu4) when the brazing temperature was 940 °C. A eutectoid microstructure consisting of α-Ti and Ti2Cu phases was produced by the eutectoid reaction (β-Ti → α-Ti + Ti2Cu) in joint when brazed at 960–1000 °C. Whereas when brazing was conducted at 1020 °C (above the α → β transus temperature 1010 °C), Lamellar(α + β) structure was obtained in joint by isothermal solidification and subsequent phase transformation. Tensile test indicated that the maximum average tensile strength reached 932.6 MPa at room temperature. Brittle fractures were observed in all of the brazed specimens although the fracture mode was different.