On the constitution of the Al-rich part of the Al–Cr–Mn system

On the constitution of Al4(Cr,Fe)

“…In contrast, in Al-Cr-Mn both binary h-phase and m-phase extend at a practically constant Al concentration [21]. The other effect of Fe is a sharp increase in the melting temperature of the h-phase, the upper value of which is only slightly lower than that of the m-phase.…”

Crystal structures and hardness of novel compounds: Hexagonal Mo(CuxAl1−x)6Al4, MoCu2Al8−x and orthorhombic {Mo,W,Re}Ni2−xAl8+x

“…A detailed TEMinvestigation indeed determined crystal symmetry and lattice dimensions corresponding to the X-phase [8,9] (a ¼ 1.0048, b ¼ 1.5423, c ¼ 0.8367 nm) for a composition Re 8 Ni 18.5 Al 73. 5 .…”

“…A recent critical assessment of the ReeNieAl system by Raghavan [7], which was based on the work of Grushko et al [8,9], interestingly revealed a ternary phase with a composition close to the X-phase from the MoeNieAl system. A detailed TEMinvestigation indeed determined crystal symmetry and lattice dimensions corresponding to the X-phase [8,9] (a ¼ 1.0048, b ¼ 1.5423, c ¼ 0.8367 nm) for a composition Re 8 Ni 18.5 Al 73.…”

“…5 . From DTA-data this phase was reported to melt incongruently at 888 C [8,9]. Although the X-ray powder diffraction pattern was indexed by Grushko and Balanetskyy [9], no structure refinement was carried out.…”

“…Whereas Prevarskiy et al [13,14] claimed the existence of two isotypic orthorhombic compounds with unknown crystal structure {Mo,W}Cu 2 Al 7 (a ¼ 0.505, b ¼ 0.841, c ¼ 1.968 nm for MoCu 2 Al 7 , but no parameters were given for WCu 2 Al 7 ), a reinvestigation with TEM by Grushko and Mi [15,16] revealed a hexagonal lattice for both these compounds [a ¼ 0.86796 (8) and c ¼ 1.51948 (12) nm for MoCu 2 Al 7 (no detailed composition given) and a ¼ 0.86594 (13) and c ¼ 1.5268(2) nm for WCu 2 Al 7 (W 12 Cu 21 Al 67 )]. From composition as well as lattice parameters, one can, however, expect a close structural relationship of these hexagonal phases with the X-phases existing in the MoeNieAl and ReeNieAl systems.…”