THERMODYNAMIC ASSESSMENT OF THE PHASE DIAGRAM OF THE TERNARY SYSTEM Y-MG-NI (Y<50 AT.)

摘要

In this study, the thermodynamic properties of the ternary system have been analyzed by means of the CALPHAD technique. The solution phases (liquid, body-centered cubic, face-centered cubic and hexagonal closed-packed) were described with the sub- stitutional solid solution model. The binary phases (NiY3, Ni2Y3, Ni2Y, Ni3Y, Ni7Y2, Ni4Y, Ni17Y2, NiY, Ni5Y, Ni7Y2 and Mg2Ni) were treated as stoichiometric compounds. Two ternary compounds (YMgNi4 and YMg2Ni9) were treated as the stoichiometric com- pounds. A self-consistent thermodynamic description of the Y-Mg-Ni system was obtained and the calculated results were compared with the available experimental information. The current calculations are in a good agreement with the experimental data reported in the literature. The ternary isothermal section of Y-Mg-Ni system calculated in this work has a more accurate phase relationship. These results are meaningful for further studies on the Y-Mg-Ni sys t em.