Microstructure and mechanical properties of Ni3Al-based alloy joint transient liquid phase bonded using Ni/Ti interlayer

Ni3Al-based alloy joints were fabricated by transient liquid phase (TLP) bonding with Ni/Ti composite interlayer. The typical interfacial microstructure of the bonded joint was primarily composed of three zones: isothermal solidification zone, athermal solidification zone and base metal. Various reaction products were observed in the bonded joint, including γ′-Ni3(Al, Ti), TiNi3, Cr-Mo-Fe rich precipitates and β-Ti. The TiNi3 phase in the athermal solidification zone was gradually reduced and eventually vanished by increasing the bonding parameters. The maximum room temperature shear strength of 828 MPa was obtained when the joint was bonded at 1220 °C for 60 min, while it was 625 MPa and 533 MPa at 650 °C and 800 °C, respectively. Cracks propagated primarily along the Ni3Al base metal and partially at the bonding interface when the joint was bonded at 1220 °C for 60 min, indicating the shear strength of the joint was almost equal to that of the base metal. •TLP bonding of Ni3Al-based alloy with Ni/Ti composite interlayer was achieved.•Ni3Al-based alloy joints had excellent room and high temperature strength.•Correlation between the joint microstructure and properties was established.