Phase equilibria of the Mg-Gd-Zn system at 500 °C

The phase equilibria of the Mg-Gd-Zn system at 500 degrees C in the region below 50 at.% Gd were investigated with equilibrated alloys, by means of the electron probe microanalysis and X-ray diffraction. Nine stable ternary phases, tau(1) to tau(8) and W, were found and their composition ranges determined. The solubility of the third elements in binary phases was well determined. W was found to be isostructural to the binary GdMg3, while a very narrow two-phase field between GdMg3 and W was determined. The tau(1) phase, with a composition range of Gd5.5-6.2Mg89.2-90.0Zn4.3-4.7, is identical to the X-phase (LPSO-14H). The tau(2) phase, with a composition range of Gd6.4-8.6Mg24.0-28.5Zn63.1-69.3, was identified to be the hexagonal Gd7.7Mg28.6Zn63.8 phase or the Z-phase in literature. The tau(3) and tau(5) phases were measured to have composition ranges of Gd10.4-10.7Mg24.0-24.5Zn64.8-65.5 and of Gd13.9-15.3Mg18.7-24.4Zn61.1-67.1, respectively, corresponding to the I-phase and the F-phase. A partial isothermal section in the region below 50 at.% Gd was constructed. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The phase equilibria of the Mg-Gd-Zn system at 500 degrees C in the region below 50 at.% Gd were studied, revealing nine stable ternary phases and establishing their composition ranges. A partial isothermal section was constructed for the region, providing valuable insight into the phase behavior of this system.