The Al-Er-Mg ternary system - Part 1: 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 degreesC has been established. An extended homogeneity region with Al substitution for Mg at a constant Er content has been found for (Mg1-xAlx)Er (0 less than or equal to x less than or equal to 0.78); a few other boundary binary phases give lower ternary solubility. A ternary compound, tau, of Al66.7Er10Mg23.3 stoichiometry, has been found to exist in the isothermal section at 400 degreesC.