Repairing of the defects of the engine vanes of an aeroplane by light beam brazing

The microstructure and hardness distribution of the dispersion strengthened Ni-based alloy ChS88 brazed by light beam in vacuum with the Vpr-42 (Ni–Cr–B–Si system) and PNC-13 (Ni–Cr–Zr system) filler metals were investigated. Because of the diffusion of boron, the brazing filler metal Vpr-42 causes the obvious erosion of the base metal. The analysis of microhardness shows that the hardness distribution of the base metal–transition zone–brazing seam with the Ni–Cr–Zr system filler metal is relatively uniform, and the hardness of the brazing seam with the Ni–Cr–B–Si system filler metal and its transition zone is obviously greater than that of base metal owing to the precipitation of the brittle and hard borides. This shows that when brazed with the Ni–Cr–Zr system filler metal by light beam, the Ni-based alloy joint has better toughness. Under the laboratory conditions, the repair of the surface defects of the vanes by means of light beam vacuum brazing with the Ni–Cr–Zr system filler metal was realized.