The effect of interlayer thickness, bonding temperature and atmosphere on transient liquid phase bonding of GTD-111 to FSX-414

The amount of gamma/nickel boride/Ni-B-Si ternary eutectic in the athermally solidified zone of joints was increased with increased thickness of the filler metal. By increasing the temperature from 1130 degrees C to 1160 degrees C, isothermal solidification was completed and no harmful phase was found in the middle of the joints. At higher temperatures, the dissolution of substrate elements prevented the diffusion of melting point depressants and the eutectic phase reappeared. Solidification cracks were observed when transient liquid phase bonding was done in non-vacuum atmospheres. The peak hardness in diffusion affected zones remained even when isothermal solidification was completed. The maximum shear strength of 412 MPa was achieved for a specimen with complete isothermal solidification (50 mu m/1160 degrees C/45 min).