Transient liquid phase diffusion bonding Al-6061 using nano-dispersed Ni coatings

Transient liquid phase diffusion bonding (TLPDB) of Al-6061 containing 15 vol.% alumina particles was carried out at various bonding temperatures. A 5 μm thick electrodeposited Ni-coating containing 18 vol.% nano-size alumina particles was used at the interlayer. Joint formation was attributed to the solid-state diffusion of Ni into the Al-6061 alloy followed by eutectic formation and isothermal solidification at the joint interface. Examination of the joint region using scanning electron microscopy (SEM), wavelength dispersive spectroscopy (WDS) and X-ray diffraction (XRD) showed the formation of intermetallic phases such as Al3Ni, Al9FeNi and Ni3Si within the joint zone. The results indicate that the incorporation of nano-size Al2O3 dispersions into the interlayer can be used to improve joint strength.

► TLP bonding of Al-6061/15%Al2O3p was studied.
► An electrodeposited Ni-coating containing nano-Al2O3p was used as interlayer.
► The effects of bonding temperature on joint properties were investigated.
► Joint strength of 137 MPa was achieved at 620 °C.
► The main factor affecting the joint strength is particle segregation.