The Al-Er-Mg ternary system Part I: Experimental investigation

Investigation of phase equilibria in the ternary system Al-Er-Mg has been carried out by means of differential thermal analysis (DTA), powder x-ray diffraction (XRD), light optical microscopy (LOM), scanning electron microscopy (SEM), and quantitative electron probe microanalysis (EPMA). The isothermal section at 400 °C has been established. An extended homogeneity region with Al substitution for Mg at a constant Er content has been found for (Mg_1−x Al _x )Er (0≤x≤0.78); a few other boundary binary phases give lower ternary solubility. A ternary compound, τ, of Al_66.7Er₁₀Mg_23.3 stoichiometry, has been found to exist in the isothermal section at 400 °C.