Isothermal section of Ga-Co-Cu phase diagram at 830 °C and its peculiarities

Recently, the Ga-based ternary alloys have gained interest for the possibility of finding new quasicrystals. Inspired by the previously reported decagonal and icosahedral quasicrystals identified in the Ga50Co25Cu25 alloy at 830 °C, the phase equilibria of 27 alloys of various composition were investigated in this work. Based on the obtained results, an isothermal section of the Ga-Co-Cu phase diagram at 830 °C was proposed. However, neither decagonal nor icosahedral quasicrystals were found to be stable at 830 °C, but instead of that, a superalloy-like structure was found in the Ga35Co25Cu40 alloy consisting of β-GaCo and β-GaCu/ζ-GaCu. [Display omitted] •Isothermal section of the Ga-Co-Cu phase diagram at 830 °C based on 27 alloys.•No stable ternary phases found, only ternary extensions of binary phases observed.•Ultrafine-structured mixture of β-GaCo and β-GaCu//ζ-GaCu was found.•β-GaCo and β-GaCu mixture resembles a superalloy-like structure.