Transient liquid phase diffusion bonding of Al/Al2O3 nanostructured metal matrix composites

Abstract

Transient liquid phase (TLP) diffusion bonding was carried out on nanostructured metal matrix composite sheets of Al-1100 alloy with 5 wt-% alumina particles at various bonding temperatures and process durations. A thin layer of 5 mm pure copper was electrodeposited as an interlayer. Joint formation was first attributed to the solid state diffusion of copper into the aluminium metal matrix followed by eutectic formation; then, base metal dissolution and isothermal solidification was completed at the joint interface. Joint area was characterised using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Diffraction patterns showed the formation of intermetallic phases like CuAl2. The concentration of Al2O3 particles increases across the interface as the bonding temperature increases. As a result, the highest bond strength of 123 MPa was achieved after a bonding duration of 30 min at 590uC.