The Effect of Strain on the Formation of an Intermetallic Layer in an Al-Ni Laminated Composite

Abstract

Abstract:In the present work, the influence of strain on phase formation at the Al/Ni interface was investigated during cold roll bonding and annealing. A sandwich sample composed of an Al-Ni-Al stack was cold rolled with reductions in the range of 50% to 90%, followed by annealing at 450 • C for 60 min. The crystallography of the annealed sandwich samples was analyzed by XRD (X-ray diffraction), whereas the microstructure was studied by scanning electron microscopy, equipped with EDS (energy dispersive spectrometer) analysis, and optical microscope. In the annealed samples, the intermetallic phase Al 3 Ni has formed at the Ni/Al interface, preferentially on the Al side of the interface. It is found that the applied strains did not have an effect on the type of intermetallic phase that was formed. However, the rolling reduction has a significant effect on the morphology of the intermetallic layer, as it was observed that after the lowest reduction of 50% only some scattered intermetallic nuclei were present, whereas at the highest rolling reduction of 90% a continuous intermetallic layer of 4.1 µm was exhibited. The formation of the intermetallic layer is discussed in terms of Al and Ni diffusion at the interface and irregular nature of the Al/Ni bonded interface after rolling reductions.

Relationship between Al-Ni intermetallic Phases and Bond Strength in Roll Bonded Steel-Aluminum Composites with Nickel Interlayers

“…The results from the electron microprobe analyzer showed that the phase had a composition of 75 at% aluminum and 25 at% nickel, consistent with the Al 3 Ni phase composition. The layer grew discontinuously along the interface, but was observed to become continuous with increasing heat treatment time, consistent with the observation made in other studies [23,24].…”

“…However, as seen in Figure 6b, with increasing heat treatment time, fewer particles could be observed inside the layer. Similar bright particles inside the Al 3 Ni layer have not been reported in other studies where the Al 3 Ni phase have been closely analyzed [23,24]. The bright particles were not subjected to any further analysis in the current study, since the work is focusing on the relationship between the Al-Ni IMP layers and the bond strength.…”

“…However, nickel interlayers in steel-aluminum joints have not been studied to the author's knowledge, despite the promising findings in the literature. The Al-Ni system and the formation and growth of Al-Ni IMPs have been thoroughly studied, and it has been shown that the two phases, Al 3 Ni 2 and Al 3 Ni are most commonly formed in the temperature range of 450 • C-610 • C [23][24][25][26]. A rigorous analysis of the growth kinetics of the two Al-Ni IMPs can be found in these articles.…”

Microstructure and Fabrication of Cu-Pb-Sn/Q235 Laminated Composite by Semi-Solid Rolling

“…Bimetallic laminated materials have received a lot of attention as a result of their excellent properties [1][2][3][4][5][6]. Better performance is acquired by the combination of advantages from the component materials.…”