Bulk synthesis by spray forming of Al–Cu–Fe and Al–Cu–Fe–Sn alloys containing a quasicrystalline phase

In this study, Al–Cu–Fe alloys without and with the addition of Sn and containing a quasicrystalline phase
were spray deposited. The spray-deposited bulk materials were characterized in terms of microstructure
and hardness. The results showed that the Al 62.5 Cu 25 Fe 12.5 alloy contains the icosahedral quasicrystalline
phase (i-phase) along with the minor k-Al 13 Fe 4 phase, whereas the Al 62.5 Cu 25 Fe 12.5 + Sn alloy contains five
phases: the major i-phase and the crystalline phases of Sn, h-Al 2 Cu, k-Al 13 Fe 4 and b-AlFe(Cu) phases.
These results have been corroborated by X-ray diffraction (XRD), scanning and transmission electron
microscopies (SEM and TEM) and differential scanning calorimetry (DSC). The hardness value of the
Al–Cu–Fe alloy reached 10.5 GPa at 50 g load and then decreased steadily with increase in the applied
load, while that for Al–Cu–Fe–Sn alloy it was originally somewhat lower, then decreased dramatically
with slight increase in the applied load but stayed constant with further load increase. The hardness
indentations in Al–Cu–Fe alloy introduced cracking in the material, whereas in the case of Al–Cu–Fe–
Sn alloy the Sn-rich areas inhibited the crack growth. The present study provides an insight into the
mechanism of phase and microstructural evolutions during spray forming of the studied alloys. Further-
more, the role of Sn in terms of microstructure and properties is highlighted.