Effect of Ni–Al₂O₃ nanocomposite coating thickness on transient liquid phase bonding of Al 6061 MMC

Abstract

Transient liquid phase diffusion bonding of Al 6061 containing 15 vol.-% alumina particles was carried out as a function of interlayer thickness. Electrodeposited Ni coatings containing 18 vol.-% nanosized alumina particles with thickness ranging from 1 to 13 mm was used as the interlayer. Joint formation was attributed to the solid state diffusion of Ni into the Al 6061 metal matrix base metal followed by eutectic formation, base metal dissolution and isothermal solidification at the joint interface. Examination of the joint region using scanning electron microscopy, wavelength dispersive spectroscopy and X-ray diffraction showed the formation of intermetallic phases such as AlFe 3 Si, Ni 17 Al 3?9 Si 5?1 O 48 and Ni 3 Si within the joint zone. The results indicated that a maximum joint strength of 92% of the base metal shear strength can be obtained if an 11 mm thick Ni-Al 2 O 3 nanocomposite coating is used as the interlayer.

Transient liquid phase (TLP) brazing of Mg–AZ31 and Ti–6Al–4V using Ni and Cu sandwich foils

“…[1][2][3][4][5][6][7] The ability to join a titanium alloy (Ti-6Al-4V) to a magnesium alloy (Mg-AZ31) can open up new avenues for product development. The Ti-6Al-4V alloy has been an attractive alloy for aerospace, marine, and chemical industries.…”

Kinetics of joint formation during diffusion induced solid state bonding of titanium and magnesium alloys

“…The properties of Ti and Mg are listed in Table 2 and shows the significant differences between the properties of the two alloys studied. Table 2: Properties of the materials used in this study [12].…”

“…Dissimilar joining of titanium and magnesium has been previously attempted using transient liquid diffusion bonding as a way of limiting intermetallic formation at the bond interface [11]. The process utilizes an interlayer which forms a liquid either by direct melting due to heating beyond the melting point of the interlayer or the formation of a eutectic reaction between the interlayer and the base metal [12]. The method has been shown to promote joining by removing surface oxide and ensuring metal-to-metal contact.…”

Nanoparticle Enhanced Eutectic Reaction during Diffusion Brazing of Aluminium to Magnesium

“…When compared to samples bonded using pure-Cu interlayer (see Figure 14B), liquid squeeze-out was prevented, since a smaller volume of liquid was formed. If the thickness of the Cu/Al 2 O 3 interlayer is reduced, the volume of liquid formed during bonding can be reduced which would prevent cavities from forming during bonding [19]. Additionally, since large external pressure is not required for diffusion brazing, a lower applied load during bonding could also prevent expulsion of the eutectic liquid.…”