On the U–Cu–Al and U–Cu–Ga systems at 600 °C

The phase relations in the U–Cu–Al and U–Cu–Ga systems have been studied at 600 °C in concentration region of 0–45/75 at.% Al and 0–40/75 at.% Ga, respectively. X-ray diffraction techniques, optical microscopy and scanning electronic microscopy, complemented with energy dispersive X-ray spectroscopy (EDS), were used to identify the phases and characterize their crystal structures and compositions. Five new ternary phases have been identified for the first time: UCu6+xAl5−x (x ∼ 0–0.2) (TbCu6.4Al4.6 structure type), UCu6+xAl5−x (x ∼ 0.38–0.68) (BaCd11 structure type), U2−ɛ(Cu7+xGa10−x)1+δ (ɛ ∼ 0.5, δ ∼ 0.03, x ∼ 0.5–1) (related to Th2Ni17 structure type), UCu5+xGa1−x (x ∼ 0–0.7) (CeCu6 structure type) and U14Cu44+xGa7−x (x ∼ 0.5–2.5) (related to Gd14Ag51 structure type). The crystal structure of the UCu5+xGa1−x and U14Cu44+xGa7−x intermetallics has been determined from X-ray single crystal counter data.