A combined experimental investigation and thermodynamic assessment was performed for the system. By using a high-temperature equilibration/quenching technique and scanning electron microscopy, electron probe microanalysis, and X-ray powder diffraction analysis, the phase equilibria at 1500 degrees C and phase stability of phase were determined. An extensive literature survey was conducted for the experimental and thermodynamic modeling data of the system. According to the literature data and the present measurements, a thermodynamic assessment was made in order to obtain a set of self-consistent thermodynamic parameters to describe the system. Based on the thermodynamic parameters acquired in this work, isothermal sections at 1100 degrees C, 1250 degrees C, 1400 degrees C, 1475 degrees C, and 1500 degrees C and the joints were calculated and compared with the available experimental data.