Wettability of GH4099 and MHC alloys by AgCuTi, TiZrCuTi and NiCrSiB filler metals and evaluation of diffusion-brazability

In order to investigate the diffusion bonding between Ni-based GH4099 alloy and Mo-based MHC alloy, the wettability of AgCuTi, TiZrCuTi and NiCrSiB filler metals on the surface of GH4099 alloy and MHC alloy was firstly performed. The results show that three kinds of filler metals have excellent wettability on the surface of two kinds of substrates, and are the suitable interlayers for joining GH4099 and MHC alloys. Secondly, diffusion bonding tests of GH4099 and MHC alloys were carried out by Gleeble thermally simulated experiments. The microstructures of three kinds of welding joints with different interlayers were compared and analyzed. It was found that Ti element had significant effects on improving the bonding strength of MHC side. A large number of Ni-Mo intermetallic compounds can easily be formed, which led to high brittleness of the joints. The experimental results showed that NiCrSiB is the best interlayer material for joining GH4099 and MHC alloys, and the shear strength of the joints can reach 116 MPa.