Nanostructured Ni/Al2O3 Interlayer: Transient Liquid Phase Diffusion Bonding of Al6061-MMC

Abstract

Aluminum metal matrix composites are materials frequently used in the automotive and aerospace industries due to their high strength-to-weight ratio, formability, corrosion resistance, and long-term durability. However, despite the unique properties of these materials, the lack of a reliable joining method has restricted their full potential in engineering applications. This article explores the effect of bonding time on transient liquid phase diffusion bonding of Al6061 containing 15 vol.% alumina particles using a 5 μm electrodeposited Ni-coating containing nano-sized alumina particles as the interlayer. Joint formation was attributed to the solid-state diffusion of Ni into the Al6061 alloy followed by eutectic formation and isothermal solidification at the joint interface. Examination of the joint region using scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction showed the formation of eutectic phases such as Al3Ni, Al9FeNi, and Ni3Si within the joint zone. The results indicate that the addition of nano-size reinforcements into the interlayer can be used to improve joint strength. The joint strength recorded was 136 MPa at a bonding time of 10 min with a marginal increase in the shear strength when the bonding time is increased to 30 min.