Effects of boron and silicon on microstructural evolution and mechanical properties of transient liquid phase bonded GH3039/ IC10 joints

Abstract To study the effects of melting point depressants (MPD), i.e., boron and silicon, on the microstructural evolution of the joints, transient liquid phase (TLP) bonding of GH3039 and IC10 single crystal was carried out using Ni-Cr-Si-B interlayers with different silicon and boron contents. The microstructural evolution of TLP bonded joints was studied by regulating the silicon and boron contents in the interlayer. It was confirmed that boron showed a much stronger impact on depressing melting point compared with silicon. A completely isothermal solidified GH3039/IC10 joints were obtained with a Ni-10Cr-5Si-3B interlayer under 1200 ℃ for holding 2 h. Finally, the effects of holding duration on the microstructural evolution and mechanical properties of the joints were studied in detail. Under 1200 ℃, a complete isothermal solidification was achieved when the bonding duration was extended to 2 h with BNi2 interlayer. The corresponding highest mean tensile strength was 730 MPa.