Crystal structure and phase stability of the Φ phase in the Al–Mg–Zn system

On the adaptability of 1/1 cubic approximant structure in the Mg–Al–Zn system with the particular example of Mg 32 Al 12 Zn 37

“…In other words, one can consider the Φ-phase to mainly occur along a parallel with the 1/1 line. This structure is adopted by several compounds which can be formulated Mg55-ε(Al1-xZnx)45+ε, x ranging from 0.44 to 0.89 [2][3][4]. The metastable phase Mg4AlZn11 known as η' phase [32] which is of little interest in the current context (far from the focused region) is not reported in the diagram.…”

“…The first, labeled Φ, has been approximated to a stoichiometric compound of formula Mg5Al2Zn2 or Mg6(Al1-xZnx)5 [2][3][4]. Its composition domain is quite narrow with a limited Mg-content (53 to 55 at.%) but spreads over a wide range of Al/Zn ratio (0.64 -1.7).…”

“…Cubic structure of type 2/1 was established for a few compositions but complete results are not always reported [15,16]. Other Mg-rich crystalline compounds displaying the orthorhombic symmetry are reported as Φ-phase, the stability of which was studied together with its relationship with icosahedral quasicrystals [2][3][4].…”

Strategies for full structure solution of intermetallic compounds using precession electron diffraction zonal data

“…The interatomic distances are given in Table 5. (Bourgeois et al, 2001) or/and to the experimental model of È-Al 17.1 Mg 53.4 Zn 29.5 (Berthold et al, 2013) (see Table 4). Both theoretical and experimental models of the È phase revealed in the Al-Mg-Zn system consisted of 23 unique atomic positions, comprising 10 Al/Zn positions with partial occupancy and 13 Mg positions with full occupancy of the atomic sites.…”

Dynamic precipitation in Mg-3Al-1Zn alloy during different plastic deformation modes

“…The approximate composition of the ɸ phase is reported as Mg 21 (Al,Zn) 17 (at.%) [12,24]. Separate theoretical calculations using Density Functional Theory (DFT) have shown that the broad homogeneity range at high temperatures corresponds to two different variants of ordered ɸ phase at 0 K, with the compositions of Mg 50 Al 16 Zn 34 and Mg 50 Al 10 Zn 40 [25], but neither of these two compositions closely match the aforementioned Mg 21 (Al,Zn) 17 phase. Thus, there currently exists a fair amount of uncertainty regarding the exact composition and structure of the ɸ phase.…”