High temperature brazing with nickel-based filler metal was carried out to study the high temperatuer brazing behavior of superalloys. Both additive metal(IN 738) and the filler metals(AMDRY DF-4B and AMS 4778) were provided in a from of mixed with ga...
High temperature brazing with nickel-based filler metal was carried out to study the high temperatuer brazing behavior of superalloys. Both additive metal(IN 738) and the filler metals(AMDRY DF-4B and AMS 4778) were provided in a from of mixed with gas atomized powders and organic binder. This brazing paste was inserted into the gap between the joining parts, and a pressure of 0.05 to IMPa was applied to joining parts. The brazing process was conducted in vacuum furnace under2×10??torr. The microstructure and porosity of the brazed area were characterised by SEM, EDX and image analyser. The Cr borides with a blocky morphology were presents in the matal braged with DF-4B filler metals. Ni-Ni₃B eutectic phase was observed in both filler metals. The area braged with DF 4B exhibited much higher porosity than the one with AMS 4778. the pressure of 0.1-0.4MPa was found to produce lower porosity.