Isothermal Sections of Al-Ni-Zr Ternary System at 850 and 1050 °C

Abstract

Phase relations of Al-Ni-Zr ternary system were investigated with more than 60 ternary alloy compositions combining with x-ray diffraction, scanning electron microscopy equipped with energy dispersive spectroscopy and electron probe microanalysis. The isothermal section at 850 °C for x(Al) < 75 at.% has been constructed. The existence of five 2-phase regions and twenty-six 3-phase regions has been confirmed. In contrast to early reported in literature, two 3-phase equilibria: γ-(Ni) + Ni5Zr + γ′-AlNi3 and Ni5Zr + Ni7Zr2 + γ′ were determined. And a large solubility of Al in Ni7Zr2 about 11.07 at.% was detected. Besides, the 1050 °C isothermal section was determined at the Ni-rich corner, where an extended homogeneity of Ni7Zr2 was observed. Differences of the equilibria in the Ni-rich corner obtained in the present work and appeared in literatures were further analyzed and discussed.