Equilibrium phases at the Ir-rich corner of the Ir–Nb–Ni–Al quaternary system

The equilibrium phases of three Ir–Nb–Ni–Al quaternary alloys at the Ir-rich corner were investigated in some detail. The phases were determined by X-ray profile as well as microstructure observation. Three phases of fcc/L12-Ir3Nb/B2-IrAl were found in two samples, and four phases of fcc/L12-Ir3Nb/L12-Ni3Al/B2-IrAl were characterized in one sample. The electron probe microanalysis (EPMA) technique was applied for analyzing the phase composition of this quaternary system. A partial quaternary phase diagram at the Ir-rich side was plotted according to the EPMA results.