Influence of interlayer thickness on diffusion brazing behavior of Al2024/AZ31 system: experimental and simulation

Diffusion brazing of Al2024 to AZ31 was carried out using Sn-based interlayer with thickness of 20, 40, 60 and 80 µm. SEM micrographs from joint zones showed that although Sn interlayer uniformly and continuously wetted the parent metals, some micro-cracks appeared in the joint brazed with 80-µm thick interlayer. The FEM simulation indicated that the joint strength increased with enhancement of interlayer thickness from 20 to 60 µm. This event was due to the increase of loading capacity with the rise in interlayer thickness. The decrease in shear strength from 60 to 80 µm interlayer thickness can be attributed to the concentration of stress in the interlayer during shear strength test. The trend of experimental results for shear strength test was also similar to the FEM outcomes.

Keywords:

brazing , FEM , microstructure , strength , stress