Microstructure evolution and brazing mechanism of Ti5Si3/Ti3Al composite and Ni-based superalloy joints using Ti-Zr-Cu-Ni filler alloy

In this study, reliable brazing of Ti5Si3/Ti3Al composite and Inconel 718 alloy was achieved using Ti-33Zr-16Cu-13Ni (wt%) filler alloy. The effect of brazing temperature on interfacial microstructure and mechanical properties of the joints was investigated. The representative microstructure of the joint brazed at 900 °C for 5 min was Ti5Si3/Ti3Al substrate/Ti3Al/Ti5Si3 + Ti2Ni + α-Ti/Ti2Ni + Fe2Ti/Cr7Ni3 + TiNi3 + Ni(Cr, Fe) solid solution/Inconel 718 substrate. The microstructure evolution mechanism of the joints was proposed based on the experimental analysis. The optimized shear strength of 208 MPa was obtained when brazing at 900 °C for 5 min. Additionally, the high temperature shear strength of the joints reached 335 MPa and 365 MPa at 600 °C and 650 °C, respectively.