Reinvestigation of the Y–Cu–Ga system at 700 °C

The ternary alloys of the Y–Cu–Ga system have been reinvestigated and the refined data on the compositions and crystal structures of the ternary compounds were received. It was shown that each extended solid solution (ThMn12-, PrFe7-, CaCu5-, BaAl4-, La3Al11-, KHg2-, CaIn2- and CsCl-type structures) consists of several individual isostructural phases, each of them reveals a partial fillings of the certain positions by yttrium or/and copper/gallium atoms. The composition of these phases gradually shifts to the higher yttrium content with increase in Ga-content. Taking into account the structural peculiarities of the extended solid solutions, 23 phases in total were found to exist in the Y–Cu–Ga system at 700 °C.

► We study the crystal structure of Ga-rich compounds in the Y–Cu–Ga system at 700 °C.
► Twenty-three phases in total were found to exist in the Y–Cu–Ga system.
► Increasing of Ga-content leads to shift of composition to the higher Y concentration.
► We analyze the behavior of atomic vacancies in the Cu/Ga positions.