Quasicrystalline phase formation in the mechanically alloyed Al–Cu–Fe system

Formation of decagonal quasicrystals in mechanically alloyed Al–Cu–Cr powders

“…Based on the DSC curve shapes, the presence of the endothermal effects in the same temperature range for some samples may be supposed. Comparing these DSC curves with those obtained earlier for the as-milled Al 65 Cu 23 Fe 12 powder [19], we can see that the temperature range of the most intensive thermal effects for the Al--Cu--Cr system lies by 100-150 C higher than that for Al--Cu--Fe system. The shape of the peaks was found to be broad for both systems.…”

“…It is known that both icosahedral [23][24][25][26] and decagonal [26][27] crystalline phases can be obtained in the Al--Cu--Cr system. As was found in [26], the decagonal phase is formed in the alloys, which are close to Al 75 Cu 12 Cr 13 in the chemical composition, whereas the icosahedral phase is formed in the Al 66 Cu 22 Cr 12 alloy, i.e., at the Al and Cu concentrations typical of the icosahedral phase in the Al--Cu--Fe system [15][16][17][18][19]. On the other hand, the formation of an icosahedral phase was observed in [27] for the Al 75 Cu 10 Cr 15 composition, i.e., the phase formation in this system depends not only on the chemical composition, but also on the method of alloy preparation.…”

“…It has been widely reported [9][10][11][12][13][14] that QC phases can be obtained by means of mechanical alloying in different systems. For instance, the Al--Cu--Fe system has attracted particular attention, because a thermodynamically stable QC phase can form in this system [14][15][16][17][18][19]. Al--Cu--Fe quasicrystalline phase was widely applied as the reinforcement [7-9, 20, 21] to obtain the composites that combine high mechanical and tribological properties; however, the corrosion resistance of QC in Al--Cu--Fe system is not high [22].…”

Formation of α-approximant and quasicrystalline Al–Cu–Fe thin films

“…A piece of the A 1 -sample was monitored with smaller temperature steps from 390 °C to more accurately determine the formation temperature of the α-phase. The α-phase first appeared after 1 h at 430 °C, which is a temperature lower than the formation temperature for the icosahedral ψ-phase mentioned in literature [12,20]. At 570 °C only the ω, with weaker intensities, and α-phases (lattice parameter, a=1.247 nm) are present.…”

“…The evolution towards the quasicrystalline ψ-Al 62.5 Cu 25 Fe 12.5 phase is known in both bulk [11,12] and thin film samples [7]. However, in order to clearly illustrate the differences in using a Si substrate (section 3.3) compared to a Al 2 O 3 substrate, sample A 1 was simultaneously deposited on both Si and Al 2 O 3 substrates and annealed using the same procedure.…”