Isothermal section of Mg-Zn-La system in Mg-rich corner at 400 ℃
(1. School of Materials and Metallurgy, Northeastern University, Shenyang 110004, China;
2. Traffic and Mechanical School, Shenyang Jianzhu University, China)
2. Traffic and Mechanical School, Shenyang Jianzhu University, China)
Abstract: Alloys with different compositions in Mg-rich corner of Mg-Zn-La system at 400 ℃ were prepared, the phase equilibrium in the Mg-rich corner of Mg-Zn-La system was determined by scanning electron microscopy(SEM), electron probe microanalysis based on energy dispersive X-ray spectroscopy (EPMA-EDS) and X-ray diffraction(XRD), and the isothermal section at 400 ℃ was established. The results show that there exists a ternary compound (T-phase) with a constant La content and changable Mg/Zn contents in the Mg-Zn-La system. The mole fraction of La in T-phase is about 8%, and that of Zn is from 16% to 43%. There exist a two-phase equilibrium which consists of T-phase plus hcp-Mg and a three-phase equilibrium which is composed of T-phase, hcp-Mg and a liquid phase (L-phase) at 400 ℃. The L-phase consists of 70% Mg, 30% Zn and is free of La.
Key words: Mg-Zn-La system; isothermal section; T-phase; phase equilibrium
shase; phase equilibrium
shase; phase equilibrium