Microstructure and mechanical properties of transient liquid phase bonding of Al2O3p/Al nanocomposite using copper interlayer

• For the first time, TLP diffusion bonding was employed for joining Al2O3p/Al nanocomposite.
• The TLP boding mechanism for nanocomposites was evaluated, comprehensively.
• The minimum bonding time was 60 min, and the final microstructure consisted of soft α-Al phase.
• The maximum joint shear strength was about 85% of the shear strength of the base material.
• The maximum joint shear strength was achieved at 580 °C for 60 min.

Transient liquid phase (TLP) bonding is one of the state-of-the-art joining processes. It is used for welding composites and advanced materials. Microstructure and mechanical properties of TLP bonding depends on the bonding time and temperature. In the current study, the effect of bonding time on the microstructure and bonding strength of the TLP diffusion bonded of Al2O3p/Al nanocomposite were investigated. A thin layer of copper deposited by electroplating was used as interlayer. With increasing the bonding time from 20 to 60 min, at a constant bonding temperature of 580 °C, the isothermal solidification was completed and the final joint microstructure consisted of soft α-Al phase with dispersed CuAl2 precipitated particles. Decreasing the amount of brittle eutectic structures in the joint seam by increasing the bonding time was the main reason for improvement of the joint shear strength. The maximum joint shear strength was achieved at 580 °C for 60 min which was about 85% of the shear strength of the base material.