Vacuum brazing effect on the interlayer failure behavior of TiAl/GH3536 hetero-thin-walled structure with BNi-2 interlayer

Abstract

In this work, BNi-2 interlayer was used to fabricate a thin-walled structure consisted of TiAl-based alloy and GH3536 alloy by vacuum brazing method and the erosion formation mechanism of TiAl/BNi-2/GH3536 thin-walled structure was discussed. The effects of brazing temperature, holding time and the thickness of interlayer on the dissolution height of GH3536 base metal, the size of brazing fillet, typical microstructural evolution and the mechanical properties of the brazed thin-walled structure were investigated in detail. When the optimized brazing parameter (1040 °C for 5 min) was selected and the interlayer thickness increased to 200μm, the maximum height of brazing fillet, dissolution height of GH3536 base metal and tensile strength of thin-walled structure achieved 420μm, 1000μm and 620 MPa, respectively. Due to the reaction between molten BNi-2 interlayer and TiAl-based alloy, the erosion readily forms for TiAl/GH3536 thin-walled structure than GH3536 thin-walled structure, especially at a relatively high brazing temperature.