Research On Phase Relations Of Al-Ni-Zr Ternary System

Abstract:Various aspects of phase diagram are of use in the industrial processing of materials that are intended to function in useful applications. Ni-based and Zr-based alloys have important applications in aerospace industry and nuclear industry. In this paper, phase relations of Al-Ni-Zr ternary system have been studied by using alloy method and CALPHAD method. A series of reasonable isothermal sections and liquid projection of Al-Ni-Zr ternary system have been built. In addition, Ni-Zr binary system was reassessment. Content is as follows:(1) Phase relations of Al-Ni-Zr ternary system were investigated combining with X-ray diffraction (XRD), scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS) and electron probe microanalysis (EPMA). The isothermal section at850℃for x(Al)<75at.%has been constructed. The existence of five2-phase regions and twenty-six3-phase regions has been confirmed. Besides, the1050℃isothermal section was determined at the Ni-rich corner, where three2-phase regions and six3-phase regions has been confirmed.(2) The microstructure of as-cast samples were further analyzed by EPMA and XRD. A series of solidification paths were established. As a basis, the phase relations of the projections of Ni-rich region and Al-rich region of Al-Ni-Zr ternary system have been built combing the interrelated binary system in literature.(3) After investigating the phase diagram and thermodynamic data in precious literature, Ni-Zr system has been optimized by CALPHAD approach, using PARROT module in Thermo-Calc software. In this paper, the selection of mixing enthalpy of liquid was discussed in detailed here. In addition, the newly published experimental data have been take into consideration.