The structure of the intermetallic phases MoAl₁₂, ReAl₁₂and TcAl₁₂

A study of the Al-rich part of the Al–Re alloy system

“…Al 12 Re Im3, Al 12 W a = 0.75200(2) - [10,12], this work a The Al 4 W-type structure suggested for this phase in [10] was not confirmed in the present study. Table 3 Powder X-ray diffraction data of Al 11 Re 4 (sample no.…”

“…Both are formed by peritectic reactions: L + Al 11 Re 4 ↔ Al 4 Re at 1404 • C and L + Al 4 Re ↔ Al 33−x Re 8 at 1008 • C. With decreasing temperature Al 4 Re decomposes by the eutectoid reaction Al 4 Re ↔ Al 11 Re 4 + Al 33−x Re 8 at ∼1008 • C. The peritectic formation of Al 12 Re and Al 6 Re as well as the L ↔ (Al) + Al 12 Re eutectic reaction were confirmed in both [9,10], but the transition temperatures were noticeably different there. For L ↔ (Al) + Al 12 Re 600 • C was given in [9] and 658 • C in [10], for L + Al 6 Re ↔ Al 12 Re 640 • C in [9] and 750 • C in [10], for L + Al 4 Re ↔ Al 6 Re 690 • C in [9] and 803 • C in [10], where low-temperature Al 33−x Re 8 is involved.…”

“…According to [6], the Al-rich region of the Al-Re phase diagram contains four compounds: cubic Al 12 Re, Al 2 Re and Al x Re y of unknown structures, and cubic Al 2 Re 3 . In [7] also orthorhombic Al 6 Re and triclinic Al 4 Re (closely related to monoclinic Al 4 Mo) were revealed with subsequent differences in the reactions between the phases.…”

“…In [7] also orthorhombic Al 6 Re and triclinic Al 4 Re (closely related to monoclinic Al 4 Mo) were revealed with subsequent differences in the reactions between the phases. The crystal structures of orthorhombic Al 6 Re and cubic Al 12 Re were determined for the phase is shown in the phase diagram as formed by a peritectic reaction from AlRe 2 and the liquid at ∼1100 • C.…”

Kinetic limit for incubation period of primary phase produced by the combination reaction between two solid heterogeneous pure metals

“…(25) and (28) indicate that the primary phase A p B q will not appear immediately after A contacts B, even though the thermodynamic condition of the reaction eq. (1) is satisfied (i.e., ΔG i <0).…”